JPH10164662A - Method and system for delivering secret key - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system for delivering a secret key by which a fist secret key can be delivered even in a radio section between a mobile station and a public base station without using such a high-degree cipher system as the public key cryptosystem. SOLUTION: After a mobile station (a) establishes an enciphered communication channel between the station (a) and a master machine A in which the station (a) is registered by using a preset second secret key KAa shared between the station (a) and machine (A), the mobile station (a) delivers a first secret key Kab to the machine A through the enciphered communication channel. Then the machine A delivers the first secret key Kab to a called wired terminal (b) through an ISDN 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secret key delivery method and system for performing end-to-end cryptographic communication via a network, and more particularly, to a mobile station and a wired terminal of a mobile communication system. The present invention relates to a method and system for securely distributing a secret key used for cryptographic communication between a mobile station and a mobile station.

[0002]

2. Description of the Related Art For example, in the second generation digital cordless telephone system standard (hereinafter referred to as RCRSTD-128), a simple confidential communication system is defined in a wireless section between a mobile station and a public base station.

[0003] In addition, an end network through a network such as ISDN is used.
As a secret key delivery method for end-to-end cryptographic communication, a secret key is delivered using an advanced encryption method such as a public key encryption method represented by RSA encryption, which does not require the delivery of a secret key in advance. The method of doing is well known.

[0004]

However, the above RCR
The simple confidential communication method in STD-128 is an encryption method only between the mobile station and the public base station in the first place, and the distribution of the secret key shared between the mobile station and the public base station is subjected to simple scrambling. However, it is hard to say that key distribution in a wireless section is always safe.

[0005] Further, since the secret key distribution system using the public key encryption system requires advanced arithmetic processing, its realization requires a considerable cost. In addition, it is generally necessary to manage the public key of each user. It is said to be difficult, and it is difficult to realize it simply.

[0006] The present invention has been made in view of the above, and an object of the present invention is to provide a wireless communication system between a mobile station and a public base station without using an advanced encryption method such as a public key encryption method. To provide a secret key distribution method and system capable of distributing a secret key.

[0007]

According to a first aspect of the present invention, there is provided a secret key distribution method, comprising: a first secret key used for cryptographic communication between a mobile station performing wireless communication with a base station and a wired terminal; A method for delivering from a mobile station to a wired terminal, wherein in order to solve the above problem, a preset second secret shared between the mobile station and a base unit with which the mobile station is registered. A key establishes a cryptographic communication path between the mobile station and the base unit,
Delivering the secret key from the mobile station to the parent device via the cryptographic communication path, and delivering the first secret key distributed from the mobile station from the parent device to the wired terminal via the wired communication network. The first secret key is delivered via the master unit.

According to the above configuration, in order to secure the security of the private key distribution between the mobile station and the base station in the first private key distribution section, that is, in the insecure wireless section, the mobile station and its mobile station are connected to each other. The second secret key is shared in advance between the base stations in which the mobile stations are registered, and a secure encrypted communication path is provided between the mobile station and the base station. Here, when the first secret key is delivered from the mobile station to the wired terminal, the mobile station temporarily sends the first secret key from the mobile station using a secure encrypted communication path with the master unit sharing the second secret key.
By distributing the first secret key to the master unit and from the master unit to a wired terminal via a wired communication network (for example, ISDN), the insecure mobile station-base station included in the delivery section of the first secret key The first secret key can be safely delivered between the two.

[0009] As a pre-setting in the present secret key distribution method, a second setting is made between the mobile station and the master unit in which the mobile station is registered.
Although it is necessary to share a secret key, generally, a master unit in which a mobile station is registered is located at the owner's house of the mobile station, and the second secret key is shared using a public key cryptosystem. It is clearly simpler than the procedure required to register a key with a public organization such as a public key management center whose reliability is required, which is required in the key distribution method (this is described in claims 2 to 16 below). The invention is also common).

[0010] The secret key distribution method according to the invention of claim 2 is characterized in that:
A method for distributing a first secret key used for encrypted communication between a mobile station performing wireless communication with a base station and a wired terminal from the wired terminal to the mobile station. Distributing the first secret key from the wired terminal to the parent device in which the mobile station is registered via a wired communication network; and setting a second secret secret set between the mobile station and the parent device. Establish a cryptographic communication path between the mobile station and the base unit using the key,
Delivering the first secret key delivered from the wired terminal to the mobile station via the encryption communication path from the master unit to the mobile station, and delivering the first secret key via the master unit.

[0011] According to the above configuration, similarly to the first aspect of the present invention, the mobile station and the parent device in which the mobile station is registered share the second secret key in advance and communicate with the mobile station. Provide a secure encrypted communication path between the master units. Here, when delivering the first secret key from the wired terminal to the mobile station, the first secret key is transmitted from the wired terminal via a wired communication network (for example, ISDN).
By temporarily delivering the first secret key from the master unit to the mobile station using a secure encrypted communication channel between the master unit and the mobile station sharing the second secret key, The first secret key can be safely delivered between the insecure mobile station and the base station included in the one secret key delivery section.

According to a third aspect of the present invention, there is provided a secret key distribution method comprising:
A method for delivering a first secret key used for cryptographic communication between a first mobile station and a second mobile station performing wireless communication with a base station from the first mobile station to the second mobile station, In order to solve the above problem, a preset second shared mobile station is shared between a first mobile station and a first master unit in which the first mobile station is registered.
A secret key is used to establish an encrypted communication path between the first mobile station and the first base unit, and the first secret key is sent to the first mobile station via the encrypted communication path.
Delivering the first secret key delivered from the first mobile station to the second base station in which the second mobile station is registered from the mobile station via a wired communication network; And establishing a cryptographic communication path between the second mobile station and the second base station by using a preset third secret key shared between the second mobile station and the second base station. Delivering the first secret key delivered from the first master unit to the second mobile station via the cryptographic communication path from the second master unit to the second mobile station. It is characterized by delivering one secret key.

According to the above configuration, the security of the secret key delivery between the first and second mobile stations and the base station in the delivery section of the first secret key, that is, the insecure wireless section, is ensured. Therefore, a second secret key is shared in advance between the first mobile station and the first master unit in which the first mobile station is registered, and also between the second mobile station and the second master unit in which the second mobile station is registered. The third secret key is shared in advance, and a secure encrypted communication path is provided between each mobile station and the master unit. Here, when delivering the first secret key from the first mobile station to the second mobile station, first,
The first secret key is delivered from the first mobile station to the first master using a cryptographic communication path established by the second secret key, and subsequently, the wired communication network (from the first master to the second master). ISDN, etc.) and then from the second master to the second mobile station using the cryptographic channel established by the third secret key to deliver the first secret key. In addition, the first secret key can be safely delivered between each insecure mobile station and the base station included in the first secret key delivery section.

According to a fourth aspect of the present invention, there is provided a secret key distribution system, comprising: a first secret key used for encrypted communication between a mobile station and a wired terminal that performs wireless communication with a base station; In order to solve the above-mentioned problem, a mobile station is registered, a master unit connected to a wired communication network is provided, and a communication between the mobile station and the master unit is provided. The mobile station and the base unit establish a cryptographic communication path between the mobile station and the base unit using the second secret key, and the first secret key is shared between the two. Means for delivering a key between the mobile station and the base unit via the cryptographic communication path, wherein the base unit transmits the first secret key received from one of the mobile station and the wired terminal to the other. A relay means for delivering, and a first relay means between the mobile station and the wired terminal via the master unit.
It is characterized by delivering a secret key.

According to the above configuration, similar to the first or second aspect of the present invention, the secret key delivery between the mobile station and the base station in the delivery section of the first secret key, ie, in the insecure wireless section. In order to ensure the security of the mobile station, a second secret key is shared in advance between the mobile station and the base unit in which the mobile station is registered, and a secure encrypted communication path is established between the mobile station and the base unit. Since the first secret key is distributed between the mobile station and the wired terminal via the master device after the provision, the insecure mobile station and the base station included in the distribution section of the first secret key are also transmitted. The first secret key can be safely delivered.

According to a fifth aspect of the present invention, in the secret key distribution system, a first secret key used for encrypted communication between a mobile station performing wireless communication with a base station and a wired terminal is transmitted from the mobile station to the wired terminal. In order to solve the above-mentioned problem, a mobile station is registered, and a master unit connected to a wired communication network is provided, and encryption is performed between the mobile station and the master unit. The mobile station shares a second secret key to be used between the two, and the mobile station has encryption means for encrypting data including at least the first secret key using the second secret key. The master unit transmits the encrypted data received from the mobile station to the master unit using a second secret key. It is characterized by transmitting to a wired terminal via a network.

According to the above configuration, similar to the first aspect of the present invention, the security of the secret key delivery between the mobile station and the base station in the delivery section of the first secret key, ie, the insecure wireless section. In order to ensure the security, the mobile station and the parent device in which the mobile station is registered share a second secret key in advance, and the mobile station having the encryption means using the second secret key, (2) Since a secure encryption communication path is provided between the base station and a base unit having a decryption unit using a secret key, the first secret key is delivered from the mobile station to the wired terminal via the base unit. The first secret key can be safely delivered between the insecure mobile station and the base station included in the one secret key delivery section.

According to a sixth aspect of the present invention, in the secret key distribution system according to the fifth aspect of the present invention, the identification information of the mobile station is transmitted from the mobile station to the wired terminal via the master unit together with the first secret key. The wired terminal has a determination unit that determines whether or not the other party is a mobile station that has requested cryptographic communication at the time of an incoming call based on the identification information of the mobile station. .

According to the above configuration, the identification information (such as the communication ID) of the mobile station on the encryption communication request side using the first secret key.
To the wired terminal on the cryptographic communication response side together with the first secret key, and the wired terminal determines whether the other party is a true cryptographic communication requesting station at the time of receiving a call (before the start of cryptographic communication). , Higher security can be ensured.

According to a seventh aspect of the present invention, in the secret key distribution system, a first secret key used for encrypted communication between a mobile station performing wireless communication with a base station and a wired terminal is transmitted from the wired terminal to the mobile station. In order to solve the above-mentioned problem, a mobile station is registered, and a master unit connected to a wired communication network is provided, and encryption is performed between the mobile station and the master unit. The two terminals share a second secret key to be used, and the wired terminal transmits the first secret key to the master via a wired communication network, and the master uses the second secret key. Having encryption means for encrypting data including at least the first secret key,
The mobile station transmits the encrypted data to the mobile station, and the mobile station includes a decryption unit that decrypts the encrypted data received from the master unit using the second secret key. .

According to the above configuration, similarly to the second aspect of the present invention, the security of the secret key delivery between the mobile station and the base station in the delivery section of the first secret key, ie, the unsecured wireless section. In order to ensure the security, the mobile station and the base station in which the mobile station is registered share a second secret key in advance, and the base station having the encryption means using the second secret key, (2) Since a secure encryption communication path is provided between the mobile station and a mobile station having a decryption means using a secret key, the first secret key is delivered from the wired terminal to the mobile station via the master unit. The first secret key can be safely delivered between the insecure mobile station and the base station included in the one secret key delivery section.

According to an eighth aspect of the present invention, in the secret key distribution system according to the seventh aspect of the present invention, the number of the wired terminal together with the first secret key is transmitted from the wired terminal to the mobile station via the master unit. The mobile station is characterized in that it has a judging means for judging, based on the identification information of the wired terminal, whether or not the other party is a wired terminal that has requested cryptographic communication when receiving a call.

According to the above configuration, the identification information (the ISDN for communication) of the wire terminal on the encryption communication requesting side by the first secret key is used.
Number, etc.) together with the first secret key to the mobile station on the cryptographic communication responding side, and this mobile station determines whether or not the other party is a true cryptographic communication requesting terminal at the time of incoming call (before starting cryptographic communication) By doing so, higher security can be ensured.

According to a ninth aspect of the present invention, in the secret key distribution system, the first secret key used for the cryptographic communication between the first mobile station and the second mobile station performing the radio communication with the base station is transmitted to the first secret key. A system for delivering from one mobile station to a second mobile station, wherein the first mobile station is registered in order to solve the above problem,
A first base unit connected to the wired communication network, a second base station registered with the second mobile station, and a second base unit connected to the wired communication network; And a second secret key used for encrypted communication between the second mobile station and the second base unit, and a second secret key used for encrypted communication between the two mobile stations is shared between the two. The first mobile station has first encryption means for encrypting data including at least the first secret key using the second secret key, transmitting the encrypted data to the first master unit, The first master unit has first decryption means for decrypting the encrypted data received from the first mobile station using a second secret key, and transmits the first secret key via a wired communication network. To the second master unit, and the second master unit uses a third secret key to encrypt second data including at least the first secret key. And, the above-described encrypted data second
The second mobile station transmits to the mobile station, and the second mobile station has a second decryption unit for decrypting the encrypted data received from the second mobile station using a third secret key.

According to the above configuration, similarly to the third aspect of the present invention, the insecure wireless section between the first and second mobile stations and the base station in the first private key delivery section. In order to secure the security of the secret key distribution in the first mobile station, the first mobile station and the first base station in which the first mobile station is registered share a second secret key in advance and register the second mobile station with the first mobile station. A second mobile terminal that has already shared a third secret key in advance, and a first mobile station having a first encryption unit using a second secret key, and a first decryption unit using a second secret key. A secure cryptographic communication path is provided between the first base unit having
After providing a secure encryption communication channel between the second mobile station having the second encryption means using the third secret key and the second master unit having the second decryption means using the second secret key, Since the first secret key is delivered from the first mobile station to the second mobile station via the first and second base stations, the insecure mobile station-base station included in the delivery section of the first secret key must Can securely deliver the first secret key.

According to a tenth aspect of the present invention, in the secret key distribution system according to the ninth aspect of the present invention, the first mobile station transmits data encrypted by the first encrypting means together with the data encrypted by the first encryption means. A first delivery request requesting delivery of the registered communication number of the second base station and the first secret key to the second mobile station via the second base station in which the second mobile station is registered is issued. The first master unit transmits the message to the first master unit, and the first master unit decodes the data by the first decoding unit in response to the notification of the communication number of the second master unit from the first mobile station and a first delivery request. A second delivery request for delivering the first secret key to the second mobile station is transmitted to the second master unit via a wired communication network together with the first secret key, and the second master unit sends the second master request to the second master unit. It is characterized in that, in response to a second delivery request from one master unit, the data encrypted by the second encryption means is transmitted to the second mobile station. It is set to.

According to the above configuration, in the configuration of the ninth aspect, the first mobile station transmits the first delivery request to the first base station together with the communication number of the second base station. The first base unit transmits the second delivery request to the second base unit, and the second base unit delivers the first secret key to the second mobile station in response to the request. Can securely deliver the first secret key from the first mobile station to the second mobile station without knowing the communication number of the second base unit.

According to the eleventh aspect of the present invention, in the secret key distribution system according to the tenth aspect of the present invention,
The mobile station transmits, to the second mobile station, a number notification request for notifying the first mobile station of the communication number of the second master unit in which the second mobile station is registered. In response to the number notification request, the first mobile station notifies the first mobile station of the communication number of the second base station, and the first mobile station transmits the communication number of the second base station from the second mobile station. Upon receipt of the notification, the communication number of the second master unit and the first delivery request are transmitted to the first master unit.

According to the above configuration, in the configuration according to the tenth aspect of the present invention, at the start of key distribution, the first mobile station notifies the first mobile station of the communication number of the second master unit. 2
A request (number notification request) is sent to the mobile station, and the second mobile station notifies the first mobile station of the communication number of the second master unit in response to the request. The first mobile station can reliably deliver the first secret key from the first mobile station to the second mobile station even if the first mobile station does not know the communication number of the second parent device.

In a twelfth aspect of the present invention, in the secret key distribution system according to the ninth aspect, the first mobile station transmits the first secret key together with the data encrypted by the first encryption means. A first delivery request for delivery to the second mobile station is transmitted to the first master unit, and the communication number of the second master unit in which the second mobile station is registered is notified to the first master unit. The second mobile station transmits a number notification request to the first base station to the first base station in response to the number notification request from the first mobile station. The first base unit receives the first delivery request from the first mobile station and the communication number of the second base unit from the second mobile station. And a second delivery request for delivering the first secret key to the second mobile station together with the first secret key decrypted by the wired communication. To the second base station, and the second base station transmits the data encrypted by the second encryption means to the second mobile station in response to the second delivery request from the first base station It is characterized by doing.

According to the above configuration, the first mobile station notifies the first mobile station of the communication number of the second master unit at the start of key distribution. A request (number notification request) is issued to the mobile station, and in response to this, the second mobile station notifies the first master unit of the communication number of the second master unit. Further, the first mobile station transmits the first delivery request to the first master unit, and in response, the first master unit transmits the first delivery request based on the communication number of the second master unit notified from the second mobile station. The second parent machine
The delivery request is transmitted, and the second master transmits the first secret key to the second mobile station in response to the delivery request. Thereby, even if neither the first mobile station nor the first base station on the cryptographic communication request side knows the communication number of the second base station before the key distribution, the first mobile station can reliably transmit to the second mobile station. The first secret key can be delivered.

According to a thirteenth aspect of the present invention, in the secret key distribution system according to the ninth aspect, the first mobile station transmits the first secret key together with the data encrypted by the first encryption means. A first delivery request for delivery to the second mobile station is transmitted to the first master unit, and the first master unit responds to the first delivery request from the first mobile station by the second mobile station. Transmits a number notification request for notifying the first master unit of the communication number of the second master unit registered with the second mobile station, and the second mobile station transmits the number notification request from the first master unit. Notifying the first master unit of the communication number of the second master unit in response to the number notification request,
Upon receipt of the communication number of the second master unit from the second mobile station, the first master unit transmits the first secret key together with the first secret key decrypted by the first decryption means to the second mobile station. A second delivery request for delivery to the station is transmitted to the second master via a wired communication network, and the second master responds to a second delivery request from the first master in response to a second delivery request from the first master. The data encrypted by the encryption means is stored in the second
It is characterized by transmitting to a mobile station.

According to the above configuration, in the configuration of the ninth aspect, the first mobile station transmits the first delivery request to the first mobile station.
If transmitted to the base unit, the first base unit requests the second mobile station to notify the first base unit of the communication number of the second base unit (number notification request), and accordingly, the second mobile station Notifies the first master unit of the communication number of the second master unit. Also, the first master unit is
The second base station transmits the second delivery request to the second base station based on the communication number of the second base station notified from the second mobile station. In response, the second base station transmits the first secret key to the second mobile station. Send Thereby, even if neither the first mobile station nor the first base unit on the encryption communication request side knows the communication number of the second base unit before key distribution,
The first secret key can be reliably delivered from the first mobile station to the second mobile station.

According to a fourteenth aspect of the present invention, in the secret key distribution system according to the ninth aspect, the first mobile station transmits the first secret key together with the data encrypted by the first encrypting means. A first delivery request for delivery to the second mobile station is transmitted to the first master unit, and the communication number of the second master unit in which the second mobile station is registered is notified to the first master unit. Sending a first number notification request to the second mobile station,
The second mobile station, in response to the first number notification request from the first mobile station, transmits a second number notification request for notifying the first master of the communication number of the second master, A second delivery request for delivering the one secret key to the second mobile station is transmitted to the second base unit, and the second base unit sends a second number notification request and a second delivery from the second mobile station. In response to the request, a third delivery request for delivering the first secret key to the second mobile station via the second master unit is transmitted to the first master unit together with the communication number of the second master unit. Receiving the first delivery request from the first mobile station, the communication number of the second base unit and the third delivery request from the second base station, and decoding the first base unit with the first decoding unit. Transmitting a fourth delivery request for delivering the first secret key to the second mobile station to the second parent device via the wired communication network, together with the first secret key thus converted, Serial second master unit, in accordance with the fourth delivery request from the first master unit, is characterized by transmitting the data encrypted in the second encryption unit to the second mobile station.

According to the above configuration, the second mobile station notifies the first mobile station of the communication number of the second base unit at the start of key distribution. In response to the request (first number notification request), the second mobile station requests the second master to notify the first master of the communication number of the second master (second number notification request). The second master unit notifies the first master unit of its own communication number in response to the request. Thereby, the second master unit can acquire the communication number of the second master unit. Further, with the above-described number notification operation in the system, the first mobile station sends the first delivery request to the first master unit, the second mobile station sends the second delivery request to the second master unit, The master sends the third delivery request to the first master,
The master unit transmits the fourth delivery request to the second master unit, so that the delivery relay of the first secret key can be performed smoothly. Thereby, the first communication on the encrypted communication request side can be performed before the key distribution.
Even if neither the mobile station nor the first master unit knows the communication number of the second master unit, it is possible to reliably deliver the first secret key from the first mobile station to the second mobile station.

According to a fifteenth aspect of the present invention, in the secret key distribution system according to the ninth aspect, the first mobile station transmits the first secret key together with the data encrypted by the first encrypting means. A first delivery request for delivery to the second mobile station is transmitted to the first master unit, and the first master unit responds to the first delivery request from the first mobile station by the second mobile station. Transmits to the second mobile station a first number notification request for notifying the first base station of the communication number of the second base station registered with the first base station, and the second mobile station transmits And delivering the first secret key to the second mobile station together with a second number notification request for notifying the first master unit of the communication number of the second master unit in response to the first number notification request from Is transmitted to the second base unit, and the second base unit transmits a second number notification request from the second mobile station. And in response to the second delivery request, the second
A third delivery request for delivering the first secret key to the second mobile station via the second master unit together with the communication number of the master unit is transmitted to the first master unit, and the first master unit transmits Receiving the first delivery request from the first mobile station, the communication number of the second base unit and the third delivery request from the second base unit, together with the first secret key decrypted by the first decryption means. Transmitting a fourth delivery request for delivering the first secret key to the second mobile station to the second parent device via the wired communication network, wherein the second parent device transmits the fourth secret request from the first parent device. (4) In response to the delivery request, the data encrypted by the second encryption means is transmitted to the second mobile station.

According to the above configuration, in the configuration of the ninth aspect, the first mobile station transmits the first delivery request to the first delivery request.
If transmitted to the master, the first master requests the second mobile station to notify the first master of the communication number of the second master (first number notification request). The mobile station requests the second master unit to notify the first master unit of the communication number of the second master unit (second number notification request). The number is notified to the first master unit. This allows
The communication number of the second master unit can be obtained. Also,
With the above number notification operation in the system, the second
The mobile station sends the second delivery request to the second master, the second master sends the third delivery request to the first master, and the first master sends the fourth delivery request to the second master. By doing so, the delivery relay of the first secret key can be performed smoothly. Accordingly, even if neither the first mobile station nor the first master unit on the encryption communication request side knows the communication number of the second master unit before the key distribution,
The first secret key can be reliably delivered from the mobile station to the second mobile station.

The secret key distribution system according to a sixteenth aspect of the present invention is the secret key distribution system according to any one of the ninth to fifteenth aspects, wherein the identification information of the first mobile station together with the first secret key is the first and the second mobile station. It is transmitted from the first mobile station to the second mobile station via the second base station, and the second mobile station has requested an encrypted communication at the time of an incoming call based on the identification information of the first mobile station. It is characterized by having a judging means for judging whether or not it is a mobile station.

According to the above configuration, the identification information (such as the communication ID) of the first mobile station on the cryptographic communication request side using the first secret key is transmitted together with the first secret key to the second mobile station on the cryptographic communication response side. And the second mobile station determines whether or not the other party is a true cryptographic communication requesting station at the time of incoming call (before the start of cryptographic communication), thereby ensuring higher security.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a system configuration according to the present embodiment. Here, a mobile station a of a mobile communication system (for example, a second generation digital cordless telephone system)
A method and system for securely delivering a first secret key Kab used for encrypted communication between a and b to a partner wired terminal b on the ISDN 1 will be described.

The ISDN 1 as a wired communication network includes:
In addition to the partner wired terminal b, a public base station 2 of a mobile communication system that performs wireless communication with a mobile station a and a base unit A in which the mobile station a is registered are communicably connected. The registration of the mobile station a with the base unit A is performed by storing the ID of the mobile station a in the storage unit of the base unit A. Master unit A
Is often installed in the home or office of the owner of the mobile station a.

With respect to the display of communication data and the like in the drawing, the ID of the mobile station a is simply “a”, the communication number (ISDN number) of the master unit A and the other party wired terminal b is simply “A”,
As in “b”, only reference numerals of each communication device are described.

As shown in FIG. 2, the mobile station a has the following functions (1) to (4). These functions are provided by, for example, a CP (not shown) built in the mobile station a.
U is realized by executing a predetermined program. Of course, it can also be realized by a dedicated circuit having each function.

(1) That is, the mobile station a generates and holds a first secret key Kab having a function of generating and holding a first secret key Kab used for cryptographic communication between the mobile station a and the other party's wired terminal b.
A holding unit 3 is provided.

(2) The mobile station a has a second secret key K used for encrypted communication with the base unit A in which the mobile station a has been registered.
A second secret key holding unit 4 having a function of holding Aa is provided. That is, the mobile station a and the master unit A each store and hold the same second secret key KAa in the nonvolatile memory.

(3) The mobile station a includes an encryption unit 5 having a function of encrypting data using the second secret key KAa. Here, the data to be encrypted includes at least the first secret key Kab. Of course, in addition to the first secret key Kab, other data to be transmitted to the base unit A, such as the communication number (hereinafter simply referred to as a number) of the other-party wired terminal b, can be encrypted.

(4) Further, the mobile station a decrypts (decrypts) the data encrypted by using the second secret key KAa with respect to the parent machine A in which the mobile station a is registered, and then connects to the other party's cable. A delivery request unit 6 having a function of requesting the terminal b to deliver the first secret key Kab is provided.

Further, as shown in FIG.
It has the functions described in the following (5) to (7).
These functions are also realized by the CPU of the master unit A executing a predetermined program or by a dedicated circuit having each function.

(5) That is, the master unit A includes the second secret key holding unit 7 having a function of holding the second secret key KAa used for the encryption communication with the mobile station a.

(6) Further, the master unit A transmits the second secret key KAa
And a decryption unit 8 having a function of decrypting the encrypted data CK from the mobile station a by using.

(7) In response to a delivery request from mobile station a, master unit A sends first secret key K to partner wired terminal b.
A delivery unit 9 having a function of delivering ab and the ID of the mobile station a is provided.

As shown in FIG. 4, the partner wired terminal b has the following functions (8) and (9). These functions are also realized by the CPU of the partner wired terminal b executing a predetermined program or by a dedicated circuit having each function.

(8) That is, the partner wired terminal b receives the ID of the mobile station a and the first secret key Kab from the master unit A, and includes the encrypted communication information holding unit 10 having a function of holding these information. doing.

(9) Also, the other party wired terminal b checks the identification information (ID, etc.) of the other party at the time of receiving a call, and determines whether or not the other party is the mobile station a which has requested the encrypted communication. It has a determining unit 11 having a function.

The secret key distribution system shown in FIG. 1 is basically realized by a mobile station a having the above-described functions, a master unit A, and a partner wired terminal b. The first secret key Kab used for encrypted communication between the mobile station a and the second secret key KAa
Wired terminal b via the encrypted communication path established by
By distributing the information to the mobile station a and the public base station 2, information can be safely delivered in an insecure wireless section included between the mobile station a and the other party's wired terminal b.

Next, the basic operation of the secret key distribution system will be described mainly with reference to FIG.

The mobile station a generates and holds the first secret key Kab by the first secret key generation / holding unit 3 of FIG. 2 when performing the encrypted communication with the partner wired terminal b (FIG. 1). Then, the generated pair (a, Kab) of the first secret key Kab and the ID of the mobile station a and the number of the other-party wired terminal b are encrypted by the encryption unit 5 in FIG.
Generate K (of FIG. 1).

Regarding the notation of encryption (encipherment), for example, a pair (a, Ka) of the first secret key Kab and the ID of the mobile station a using the second secret key KAa as described above.
b) and data CK obtained by encrypting the number of the wired terminal b
Is generated, CK = EKAa (b, (a, Ka
b)). Also, decoding (deciherment)
For example, in the case of decryption of the encrypted data CK, the notation is expressed as (b, (a, Kab)) = DKAa (CK).

Next, the mobile station a sends the encrypted data CK to the base unit A in which the mobile station a has been registered by the delivery request unit 6 in FIG.
(FIG. 1), and sends the first secret key Kab to the master unit A.
Requesting delivery to the other-party wired terminal b.

Master unit A decrypts encrypted data CK received from mobile station a by decryption unit 8 in FIG.
The first secret key Kab and the number of the destination wired terminal b of the delivery destination are obtained (of FIG. 1). Then, the master unit A is the delivery unit 9 in FIG.
Distributes the first secret key Kab and the ID of the mobile station a to the other party wired terminal b (FIG. 1).

The above-mentioned wired terminal b holds the first secret key Kab and the ID of the mobile station a received from the master unit A in the encrypted communication information holding unit 10 in FIG. Wait for the start of the encrypted communication with the station a. Thereafter, the other party's wired terminal b checks the identification information (ID or number) of the other party at the time of the incoming call, and if the other party is the mobile station a that has requested the cryptographic communication, the mobile station b moves using the first secret key Kab. The encryption communication with the station a is started (FIG. 1).

Next, a communication sequence of the above-described secret key distribution system will be described with reference to FIGS.

First, an embodiment using a call providing service called ISDN1 call transfer will be described with reference to FIG. The call transfer service is an additional service for transferring a call in progress to another user / network interface.

First, the mobile station a generates the first secret key Kab (make (Kab)) as described above, and the pair of the first secret key Kab and the ID of the mobile station a and the partner wired terminal b Data CK is generated by encrypting the number (CK = E
KAa (b, (a, Kab))). Next, mobile station a
The encrypted data CK is added to the user / user information element in the “call setting” message (Setup) for the base unit A.
And make a call to the master unit A. The above-mentioned “call setting” message is sent to base unit A via public base station 2 and ISDN 1. In the following, description of the message relay operation of the public base station 2 and the ISDN 1 will be omitted.

The above-mentioned master unit A receives the above-mentioned “call setting” message and acquires the encrypted data CK (Get (C
K)), and decrypts the encrypted data CK to obtain the first secret key Kab, the ID of the mobile station a, and the number of the wired terminal b ((b, (a, Kab)) = DKAa (C
K)). Next, in response to the incoming call from mobile station a, master unit A returns a “response” message (Connect),
Establish a call. Thereafter, master unit A requests the above-mentioned call transfer (CT) from ISDN 1 and suspends the call with mobile station a. Then, the “call setting” message for partner wired terminal b and the ID of mobile station a and the first A call is made to the other party's wired terminal b with one secret key Kab included.

The above-mentioned wired terminal b receives the above-mentioned “call setting” message from the master unit A, and receives the ID of the mobile station a and the first
Acquire the secret key Kab (Get (a, Kab)). Further, the partner wired terminal b returns a “response” message to the parent device A, and thereafter waits for the start of encrypted communication using the first secret key Kab.

The master unit A receives the "response" message from the partner wired terminal b, and when a call with the partner wired terminal b is established, requests the ISDN 1 for a call transfer.
The call to the mobile station a is transferred to the other party wired terminal b.

Thus, a call is established between the mobile station a and the other party's wired terminal b, and encryption communication (private communication) using the first secret key Kab is started between the two.

Next, an embodiment in which the above-mentioned call transfer service is not used will be described. In ISDN1, when the basic interface is used as the user / network interface, two B channels can be used at the same time. (When the primary rate interface is used as the user / network interface, the simultaneous use of a plurality of channels is required.) Is possible). Therefore, master unit A
Can have two calls at the same time without using supplementary services such as call transfer. Therefore, a communication sequence when two calls can be held at the same time will be described below with reference to FIG.

The mobile station a generates the first secret key Kab (m
ake (Kab)), the encrypted data CK is calculated (CK = EKAa ((b, (a, Kab))), this is included in the “call setting” message, and a call is made to the base unit A. Master A receives the “call setting” message, acquires encrypted data CK (Get (CK)), and decrypts the encrypted data CK ((b, (a, Kab)) = DK.
Up to Aa (CK)) is the same as the communication sequence in FIG.

Thereafter, master unit A does not immediately respond to the call from mobile station a, but instead notifies mobile station a of a call in progress (Alert).
(A)) to maintain the call with the mobile station a in the ringing state.

Next, master unit A sends the ID of mobile station a and the first secret key K to the “call setup” message for partner wired terminal b.
A call is made to the other party's wired terminal b with ab included. Upon receiving the "call setting" message from the master unit A, the partner wired terminal b acquires the ID of the mobile station a and the first secret key Kab (Get (a, Kab)).

Next, the other party wired terminal b does not immediately respond to the call from the base unit A, but sends a “call” message (Alert (A)) to the base unit A, and thereafter to the base unit A. On the other hand, a "disconnect" message (Dis
c (A)) to disconnect the channel.

The master unit A recognizes that the other party's wired terminal b has acquired the first secret key Kab or the like by receiving the “disconnect” message from the other party's wired terminal b, and then sends the mobile station a a “ Disconnect message (Disc (a))
To disconnect the channel and release (disconnect) the call with the mobile station a, which has been maintained in the paging state.

The mobile station a receives the “disconnect” message from the master unit A, and transmits the first
Recognizing that the delivery of the secret key Kab is completed,
The “call setting” message for the other party's wired terminal “b” includes the ID of the mobile station “a” and calls the other party's wired terminal “b”.

Upon receiving the "call setting" message, the other party wired terminal "b" confirms that the ID of the calling side is that of the mobile station "a" requesting the encrypted communication, and returns a "response" message.

Thus, a call is established between the mobile station a and the other party's wired terminal b, and encryption communication (secret communication) using the first secret key Kab is started between the two.

Next, another embodiment in which the call transfer service is not used will be described. As described above, in ISDN1, two B
You can have two calls at the same time depending on the channel,
It is also possible that only one B channel is available.
Therefore, a communication sequence when only one call is allowed will be described below with reference to FIG.

The mobile station a generates the first secret key Kab (m
ake (Kab)), the encrypted data CK is calculated (CK = EKAa ((b, (a, Kab))), this is included in the “call setting” message, and a call is made to the base unit A. Master A receives the “call setting” message, acquires encrypted data CK (Get (CK)), and decrypts the encrypted data CK ((b, (a, Kab)) = DK.
Up to Aa (CK)) is the same as the communication sequence in FIG.

Thereafter, master unit A does not immediately respond to the call from mobile station a, but sends a “call” message to mobile station a, and then sends a “disconnect” message to mobile station a. And release (disconnect) the call. Then mobile station a
Waits until there is a call from master unit A.

On the other hand, master unit A sends the ID of mobile station a and the first secret key K
A call is made to the other party's wired terminal b with ab included. Upon receiving the "call setting" message from the master unit A, the partner wired terminal b acquires the ID of the mobile station a and the first secret key Kab (Get (a, Kab)).

Next, the other party wired terminal b does not immediately respond to the call from the base unit A, but sends a “call” message to the base unit A, and then sends a “disconnect” message to the base unit A. To disconnect the channel.

The master unit A recognizes that the other party's wired terminal b has acquired the first secret key Kab or the like by receiving the “disconnect” message from the other party's wired terminal b. The call is transmitted to the mobile station a with the "call setting" message including "information I indicating completion of key distribution".

After receiving the above-mentioned "call setting" message and confirming the completion of the key distribution, the mobile station a transmits a "disconnect" message to the master unit A to release the call, and then releases the call to the partner wired terminal b. A call is sent to the partner wired terminal b with the "call setting" message including the ID of the mobile station a.

[0086] Receiving the "call setting" message, the other party wired terminal b confirms that the ID of the calling side is that of the mobile station a that has requested the cryptographic communication, and returns a "response" message.

As a result, a call is established between the mobile station a and the partner wired terminal b, and cipher communication (private communication) using the first secret key Kab is started between the two.

In the above description, not only the first secret key Kab but also the ID of the mobile station a and the number of the wired terminal b are encrypted with the second secret key KAa and transmitted from the mobile station a to the master unit A. However, the present invention is not limited to this, and at least the first secret key Kab may be encrypted. However, since the ID of the mobile station a and the number of the wired terminal b of the other party are also encrypted as described above, it becomes difficult to identify the target of the encrypted communication, and the information is not inadvertently given to the eavesdropper. More preferred.

As described above, the secret key distribution system according to the present embodiment uses the first key used for the cryptographic communication between the mobile station a that performs wireless communication with the public base station 2 and the wired terminal b. A system for delivering a secret key Kab from a mobile station a to a partner wired terminal b, using (i) a second secret key KAa shared with a base unit A in which the mobile station a is registered. It has an encryption means (encryption unit 5 in FIG. 2) for encrypting data including at least the first secret key Kab, and delivers the first secret key Kab to the other party wired terminal b together with the above-described encrypted data. And (ii) decryption means for decrypting the encrypted data received from the mobile station a using the second secret key KAa. (Decoding unit 8 in FIG. 3), A configuration in which a said master unit A to the first secret key Kab and transmits to the other wire terminal b in accordance with the.

Accordingly, even in an insecure wireless section (ie, a section between mobile station a and public base station 2) included between mobile station a and partner wired terminal b, first secret key Kab of first secret key Kab can be obtained. Delivery can be done safely.

In the above configuration, the first secret key K
ab and the ID of the mobile station a through the base unit A.
To the other-party wired terminal b, and determines whether or not the other-party wired terminal b is the mobile station a that has requested the cryptographic communication at the time of the incoming call based on the ID of the mobile station a. Higher security can be secured. Further, by distributing the first secret key Kab and the identification information (ID of the mobile station a) of the encrypted communication requesting side to the encrypted communication responding side in this way, the partner wired terminal b of the encrypted communication responding side Can reliably determine with which mobile station the received first secret key Kab is a secret key for performing cryptographic communication.

By the way, the method and the system for delivering the first secret key Kab from the mobile station a to the partner wired terminal b have been described above. Next, as shown in FIG. A method and system for delivering the first secret key Kab to a will be described.

In this case, as shown in FIG.
Includes a first secret key generation / holding unit 12 having a function of generating / holding a first secret key Kab used for cryptographic communication with the mobile station a. Further, the wired terminal b has a function of requesting the parent device A in which the mobile station a is registered to deliver the first secret key Kab and the number (identification information) of the wired terminal b to the mobile station a. Is provided.

Further, as shown in FIG. 10, master unit A uses second secret key holding unit 7 having a function of holding second secret key KAa and second secret key KAa to store data (at least (Including one secret key Kab) and a function of delivering the encrypted first secret key Kab to the mobile station a in response to a delivery request from the wired terminal b. Is provided. Here, the encryption unit 14 sends the first private key Kab together with the wired terminal b.
And the delivery unit 15 also encrypts the first secret key Ka
b and encrypted data CK including a pair of wired terminal b
To the mobile station a.

As shown in FIG. 11, the mobile station a
The second secret key holding unit 4 having a function of holding the second secret key KAa, and the decoding unit 1 having a function of decoding the encrypted data CK from the master unit A using the second secret key KAa.
6, the first secret key Kab obtained by decryption and the wired terminal b
Communication information storage unit 17 having a function of storing the
And a determination unit 18 having a function of checking the identification information of the other party at the time of receiving a call and determining whether or not the other party is the wired terminal b that has requested the encrypted communication.

Next, the basic operation of the secret key distribution system shown in FIG. 8 will be described.

When performing an encrypted communication with the partner mobile station a, the wired terminal b generates and holds the first secret key Kab by the first secret key generation / holding unit 12 in FIG. 9 (FIG. 8). Next, the wired terminal b sends the pair (b, Kab) of the generated first secret key Kab and the number of the wired terminal b and the ID of the mobile station a to the mobile station a by the delivery request unit 13 of FIG.
Is delivered to the registered base unit A (FIG. 8),
Requesting the delivery of the first secret key Kab and the like to the mobile station a.

[0098] The above-mentioned master unit A transmits a pair (b, b) of the first secret key Kab received from the wired terminal b and the number of the wired terminal b.
Kab) is encrypted by the encryption unit 14 of FIG. 10 (FIG. 8), and the encrypted data CK thus obtained is
0 to the mobile station a (FIG. 8).

The mobile station a decrypts the encrypted data CK received from the master unit A by the decryption unit 16 shown in FIG. 11, and stores the first secret key Kab and the number of the wired terminal b of the communication partner (identification information). ) Is obtained (FIG. 8), and the first secret key Kab and the number of the wired terminal b are stored in the encrypted communication information storage unit 17 in FIG. 11 (FIG. 8), and the encrypted communication with the wired terminal b is performed. Wait for start. Thereafter, the mobile station a checks the identification information (ID or number) of the other party at the time of receiving the call, and if the other party is the wired terminal b that has requested the encrypted communication,
The encrypted communication with the wired terminal b using the first secret key Kab is started (FIG. 8).

In the above description, the wired terminal b is connected to the partner mobile station a.
Is assumed to recognize the number of the parent device A registered. However, there may be a case where the wired terminal b does not know the number of the parent device A. Therefore, next, a method in which the wired terminal b acquires the number of the master unit A of the partner mobile station a will be described.

One of the above methods is as follows.
Directly sends a call to the partner mobile station a, transmits a number notification request for notifying the wired terminal b of the number of the base unit A to the mobile station a, and receives the number notification request from the mobile station a. a
In this method, the number of the master unit A is notified to the wired terminal b in response to the request.

As another method, first, the wired terminal b
Sends a first number notification request to the mobile station a requesting to notify the wired terminal b of the number of the base unit A by directly calling the other mobile station a. The mobile station a that has received the request transmits a second number notification request to notify the wired terminal b of the number of the base unit A to the base unit A, and the base unit that has received the second number notification request. There is also a method in which A notifies the wired terminal b of its own number. However, since this method only complicates the communication sequence as compared with the above method, it is preferable to use the above method.

After the wired terminal b obtains the number of the master unit A of the partner mobile station a by the above-described method, the first secret key Kab is transferred from the wired terminal b to the partner mobile station b by the aforementioned method shown in FIG. It can be safely delivered to the station a. In this case, as in the case of the key distribution from the mobile station a to the partner wired terminal b described above,
A sequence that uses the call transfer service,
Key distribution can be realized by a sequence that uses two calls at the same time without using the service, or a sequence that does not use the service and does not use two calls at the same time.

If both mobile station a and master unit A have both encryption means and decryption means for establishing an encrypted communication path using the second secret key KAa, mobile station a
Will be able to deliver and receive the first secret key Kab.

By the way, between the mobile station a and the master unit A in which the mobile station a is registered, the cipher communication using the second secret key KAa is possible as described above, but other secret keys are used. When cryptographic communication is required, a desired secret key may be exchanged via a cryptographic communication path established by the second secret key KAa, and cryptographic communication may be performed using the desired secret key. Also, when changing the second secret key KAa shared between the mobile station a and the master unit A, the second secret key KAa
The secret key desired to be changed may be exchanged via the cryptographic communication path established by the above.

[Embodiment 2] Another embodiment of the present invention will be described below with reference to FIGS.

The system configuration according to the present embodiment is shown in FIG.
Is shown in Here, a first secret key Ka used for cryptographic communication between the first mobile station a and the second mobile station b is used for encryption communication between the two mobile stations a and b.
A method and system for safely delivering b will be described.

The ISDN 1 as a wired communication network includes:
Wireless communication between the public base station 2a of the mobile communication system that performs wireless communication with the first mobile station a, the first master unit A in which the first mobile station a is registered, and the second mobile station b The public base station 2b of the mobile communication system that performs the above and the second base station B in which the second mobile station b is registered are communicably connected.

Note that the first mobile station a and the second mobile station b are subscribed to the mobile communication system of the same operator, and the distance between them is not so large that the first mobile station a and the second mobile station b are in the same base station area. , The public base station 2a and the public base station 2b may be the same.

The registration of the first and second mobile stations a and b with the first and second base units A and B is performed by storing the ID of each mobile station in the storage unit of the corresponding base unit. . The first
In addition, the second base units A and B are often installed in the homes and offices of the owners of the first and second mobile stations a and b.

[0111] Regarding the display of communication data and the like in the drawing, the IDs of the first and second mobile stations a and b are simply "a".
And "b", the numbers of the first and second master units A and B (ISDN
No.) describes only the reference numerals of the respective communication devices, such as “A” and “B”.

As shown in FIG. 13, the first mobile station a has the following functions (2-1) to (2-5). These functions are realized by the CPU of the first mobile station a executing a predetermined program or by a dedicated circuit having each function.

(2-1) That is, the first mobile station a has a first secret key having a function of generating and holding a first secret key Kab used for cryptographic communication between itself and the second mobile station b. A generation / holding unit 21 is provided.

(2-2) Further, the first mobile station a uses the second mobile station a for the cryptographic communication with the first base unit A with which the first mobile station a is registered.
A second secret key holding unit 22 having a function of holding the secret key KAa is provided. That is, the first mobile station a and the first master unit A each store and hold the same second secret key KAa in a nonvolatile memory.

(2-3) The first mobile station a has a function of encrypting data (including at least the first secret key Kab) using the second secret key KAa. A part 23 is provided.

(2-4) Further, the first mobile station “a” is, with respect to the second mobile station “b”, a second base station B in which the second mobile station “b” is registered.
Is provided with a number notification request unit 24 having a function of transmitting a number notification request for notifying the first mobile station a of the number.

(2-5) Further, the first mobile station a receives the number of the second base station B from the second mobile station b, and sends the ID of the first base station A to the first base station A. And a first secret key Kab, and a first delivery request unit 25 having a function of transmitting a "first delivery request for requesting delivery to the second mobile station b via the second base unit B". I have.

As shown in FIG. 14, the first master unit A has the following functions (2-6) to (2-8). These functions are also realized by the CPU of the first master unit A executing a predetermined program or by a dedicated circuit having each function.

(2-6) That is, the first master unit A uses the second secret key KAa used for the encrypted communication with the first mobile station a.
And a second secret key holding unit 26 having a function of holding

(2-7) Further, the first master unit A transmits the second secret key K
Aa, encrypted data C from the first mobile station a
A first decoding unit 27 having a function of decoding K is provided.

(2-8) Further, the first master unit A receives the first delivery request from the first mobile station a, and sends the “first mobile station a ID” to the second master unit B. And a first secret key Kab. The second delivery request unit 28 has a function of transmitting a "second delivery request for requesting delivery of a pair (a, Kab) to the second mobile station b".

As shown in FIG. 15, the second master unit B has the following functions (2-9) to (2-11). These functions are also realized by the CPU of the second master unit B executing a predetermined program or by a dedicated circuit having each function.

(2-9) That is, the second master unit B uses the third secret key KBb used for encrypted communication with the second mobile station b.
And a third secret key holding unit 29 having a function of holding the secret key. That is, the second mobile station b and the second master unit B each store and hold the same third secret key KBb in a nonvolatile memory.

(2-10) The second master unit B uses the third secret key KBb to encrypt data (including at least the first secret key Kab). A unit 30 is provided. Here, the second encryption unit 30
Encrypts the pair (a, Kab) of the ID of the first mobile station a and the first secret key Kab received from the first master unit A using the third secret key KBb, and CK ′ = EKBb (a, Ka
b) is calculated.

(2-11) The second master unit B receives the second delivery request from the first master unit A, and delivers the encrypted data CK ′ to the second mobile station b. A delivery unit 31 having a function is provided.

As shown in FIG. 16, the second mobile station b has the following functions (2-12) to (2-16). These functions are also realized by the CPU of the second mobile station b executing a predetermined program or by a dedicated circuit having each function.

(2-12) That is, the second mobile station b has the third secret key holding unit 32 having the function of holding the third secret key KBb.

(2-13) The second mobile station b uses the third secret key KBb to decrypt the encrypted data CK 'from the second master unit B. Is provided.

(2-14) The second mobile station b has an encrypted communication information holding unit 34 having a function of holding the decrypted first secret key Kab and ID of the first mobile station a. ing.

(2-15) The second mobile station b confirms the identification information (ID or number) of the other party at the time of the incoming call, and is the first mobile station a from which the other party has requested cryptographic communication. A determination unit 35 having a function of determining whether or not the determination is made is provided.

(2-16) Further, the second mobile station b has a function of receiving the number notification request from the first mobile station a and notifying the first mobile station a of the number of the second master unit B. And a master unit number notifying unit 36.

The present secret key distribution system shown in FIG. 12 basically has the first and second mobile stations a.
b and the first and second master units A and B,
A first mobile station a and a second mobile station b used for cryptographic communication.
The secret key Kab is transmitted to the encrypted communication path established by the second secret key KAa shared between the first mobile station a and the first base unit A, and between the second mobile station b and the second base unit B. By distributing from the first mobile station a to the second mobile station b via the cryptographic communication path established by the third secret key KBb shared between the two mobile stations a and b, Key distribution is safely performed in an insecure wireless section, that is, a section between the first mobile station a and the public base station 2a and a section between the second mobile station b and the public base station 2b.

Next, the basic operation of the secret key distribution system will be described mainly with reference to FIG.

First, the first mobile station a sends the second base station B to the second mobile station b by the number notification request unit 24 in FIG.
1 is notified to the first mobile station a (FIG. 1).
On the other hand, the second mobile station b notifies the first mobile station a of the number of the second base station B to the first mobile station a by the base station number notification section 36 in FIG. (Number response in FIG. 12).

Further, the first mobile station a generates and holds the first secret key Kab for encrypted communication with the second mobile station b by the first secret key generation / holding unit 21 of FIG. 12), the first encryption key 23 of FIG.
b is encrypted to obtain CK (FIG. 12). The above key generation and encryption operations may be performed before the above number request and response operations.

The first mobile station a sends the number of the second base station B notified from the second mobile station b to the first base station A by the first delivery request section 25 in FIG. Mobile station b ID,
The data (B, b, (a, CK)) including the pair (a, CK) of the ID of the first mobile station a and the encrypted data CK is delivered (FIG. 12), and the first master unit A Requesting that the information (excluding the number of the second master unit B) be delivered to the second master unit B (first delivery request).

The first master unit A, which has received the transmission data (B, b, (a, CK)) from the first mobile station a,
First, the first decryption unit 27 in FIG. 14 decrypts the encrypted data CK to obtain a first secret key Kab (FIG. 12).
of). Then, the first master unit A sends (b, Kab) to the second master unit B in order to request that (a, Kab) be delivered to the second mobile station b by the second delivery request unit 28 in FIG. (A, K
ab)) (FIG. 12).

From the first master unit A, (b, (a, Ka)
b)) receives the (a, Ka) using the third secret key KBb by the second encryption unit 30 of FIG.
b) is encrypted to obtain CK '(FIG. 12). Then, the second master unit B distributes the encrypted data CK ′ to the second mobile station b by the distribution unit 31 of FIG. 15 (see FIG. 12).

The second mobile station b having received the above-described encrypted data CK ′ is transmitted to the second mobile station b by the second decryption unit 33 of FIG.
To obtain (a, Kab) ((10) in FIG. 12),
The obtained ID of the first mobile station a and the first secret key Kab are
The encrypted communication information is held in the encrypted communication information holding unit 34 in FIG. Then, the second mobile station b
Confirms the identification information (ID or number) of the other party at the time of the incoming call, and starts the encrypted communication using the first secret key Kab if the other party is the first mobile station a requesting the encrypted communication. ((11) in FIG. 12).

Next, a case where a call transfer service is used will be described as an example of a communication sequence of the secret key distribution system with reference to FIG.

The first mobile station a transmits the "call setup" message to the second mobile station b, including a request for notification of the number of the second base station B in which the second mobile station b is registered. Station b
Make a call to. The second mobile station b transmits a “response” message including the number of the second base unit B to the “call setting” message from the first mobile station a. The first mobile station a
Upon receiving the number notification of the second master unit B from the mobile station b (Ge
At t (B)), a “disconnect” message is transmitted to the second mobile station b, and the call with the second mobile station b is immediately disconnected.

During or after the above operation, the first mobile station a
Generates a first secret key Kab (make (Ka
b)), calculate the encrypted data CK using the second secret key KAa (CK = EKAa (Kab)). Then the first
The mobile station a stores the number of the second base station B, the ID of the second mobile station b, the ID of the first mobile station a, and the encrypted data CK in the “call setup” message for the first base station A. Including the first
Place a call to master unit A.

The first master unit A receives the “call setup” message from the first mobile station a, acquires the data contained in the message (Get (B, b, a, CK)), The encrypted data CK therein is decrypted and the first secret key Kab is decrypted.
(Kab = DKAa (CK)). Further, the first master unit A responds to the incoming call from the first mobile station a by “responding”.
Return the message and establish the call. Next, the first master unit A
Calls ISDN for Call Transfer Service
1 and suspends the call with the mobile station a. Then, during the “call setup” message for the second base station B,
A call is made to the second base station B, including D, the ID of the first mobile station a, and the first secret key Kab.

The second master unit B receives the “call setting” message from the first master unit A, acquires the data contained in the message (Get (b, a, Kab)), and acquires the data therein. Of the first mobile station a and the first secret key Kab using the third secret key KBb to obtain CK ′ (CK ′)
= EKBb (a, Kab)). Further, second master unit B returns a "response" message to the incoming call from first master unit A.

When the first master unit A receives the "response" message from the second master unit B and the call with the second master unit B is established, the first master unit A requests the ISDN 1 for a call transfer, and
The call to the mobile station a is transferred to the second master unit B. This allows
When a call is established between the first mobile station a and the second base station B, the second base station B requests a call transfer from the ISDN 1 and suspends the call with the first mobile station a. A call is made with the above-mentioned encrypted data CK 'included in the "call setting" message for the second mobile station b.

The second mobile station b receives the “call setup” message from the second master unit B, acquires the encrypted data CK ′ (Get (CK ′)), and decrypts it with the third secret key KBb. To obtain the ID of the first mobile station a and the first secret key Kab ((a, Kab) = DKBb (CK ')). Further, the second mobile station b returns a "response" message to the second base station B and connects the channel, and then waits for the start of cryptographic communication with the first mobile station a.

When receiving the "response" message from second mobile station b, second base station B requests ISDN 1 for a call transfer, and transfers the call with first mobile station a to second mobile station b. . As a result, a call between the first mobile station a and the second mobile station b is established, and encryption communication (private communication) using the first secret key Kab is started between the two.

Next, a description will be given of a communication sequence in the case where the call transfer service is not used in the secret key distribution system of FIG. 12 particularly when two calls can be held at the same time with reference to FIG.

The number request / response of the second master unit B between the first mobile station a and the second mobile station b is the same as the communication sequence of FIG. Further, the first mobile station a
After generating the secret key Kab (make (Kab)), the encrypted data CK is calculated (CK = EKAa (Ka
b)), a call is made to the first master unit A with various data included in the “call setting” message, and then the first master unit A receives the “call setting” message and acquires data (Get (B) , B,
a, CK)), and the process up to decrypting the encrypted data CK therein (Kab = DKAa (CK)) is the same as the communication sequence of FIG.

Then, instead of immediately responding to the call from the first mobile station a, the first master unit A sends a "call" message to the first mobile station a, and the first base station A communicates with the first mobile station a. Call is kept ringing.

Next, the first master unit A makes a call with the “call setup” message for the second master unit B including the IDs of the first and second mobile stations a and b and the first secret key Kab. I do. The second master unit B receives the “call setup” message from the first master unit A, acquires the data included in the message (Get (b, a, Kab)), and acquires 1 mobile station a
ID and the first secret key Kab are encrypted using the third secret key KBb to calculate CK ′ (CK ′ = EKBb)
(A, Kab)). The second master unit B is connected to the first master unit A
Instead of immediately responding to the call from, the "ringing" message is sent to the first master unit A, and the call with the first master unit A is maintained in the ringing state.

Next, the second master unit B sends the above-mentioned encrypted data CK ′ to the “call setting” message for the second mobile station b.
And make a call. The second mobile station b receives the “call setup” message from the second master unit B, acquires data included in the message (Get (CK ′)),
The encrypted data CK ′ is decrypted using the third secret key KBb to obtain the ID of the first mobile station a and the first secret key Kab ((a, Kab) = DKBb (CK ′)). Also, the second
The mobile station b sends a “call” message to the second base station B instead of immediately responding to the call from the second base station B, and then sends a “disconnect” message to the second base station B. Transmit and disconnect the channel.

The second master unit B disconnects from the second mobile station b.
Upon receiving the message, the second mobile station b recognizes that it has obtained the first secret key Kab and the like, and then,
A "disconnect" message is transmitted to the base unit A to disconnect the call with the first base unit A which has been maintained in the calling state.

The first master unit A recognizes that the key delivery to the second mobile station b via the second master unit B has been completed by receiving the “disconnect” message from the second master unit B, Thereafter, a "disconnect" message is transmitted to the first mobile station a to disconnect the call with the first mobile station a which has been maintained in the paging state.

The first mobile station “a” disconnects from the first master unit A.
By receiving the message, it recognizes that the key distribution to the second mobile station b via the first main unit A and the second main unit B has been completed, and thereafter, "call setting" is performed for the second mobile station b. And send a call. The second mobile station b that has received the “call setup” message confirms that the source ID (calling identification code) is that of the first mobile station a that has requested the cryptographic communication, and then transmits to the first mobile station a. Reply a "response" message. As a result, a call between the first mobile station a and the second mobile station b is established, and encryption communication (private communication) using the first secret key Kab is started between the two.

Next, a description will be given of a communication sequence in a case where the private key distribution system of FIG. 12 does not use the call transfer service and has only one call, with reference to FIG.

The number request / response of the second base unit B between the first mobile station a and the second mobile station b is the same as the communication sequence of FIG. Further, the first mobile station a
After generating the secret key Kab (make (Kab)), the encrypted data CK is calculated (CK = EKAa (Ka
b)), a call is made to the first master unit A with various data included in the “call setting” message, and then the first master unit A receives the “call setting” message and acquires data (Get (B) , B,
a, CK)), and the process up to decrypting the encrypted data CK therein (Kab = DKAa (CK)) is the same as the communication sequence of FIG.

Thereafter, the first master unit A sends a "call" message to the first mobile station a, and further sends a "disconnect" message to the first mobile station a to disconnect the call. Thereafter, the first mobile station a stands by until there is a call from the second mobile station b.

Next, the first master unit A makes a call with the "call setup" message for the second master unit B including the IDs of the first and second mobile stations a and b and the first secret key Kab. I do. The second master unit B receives the “call setup” message from the first master unit A, acquires the data included in the message (Get (b, a, Kab)), and acquires 1 mobile station a
ID and the first secret key Kab are encrypted using the third secret key KBb to calculate CK ′ (CK ′ = EKBb)
(A, Kab)). The second master unit B is connected to the first master unit A
To the first master unit A, and disconnects the call.

Next, the second base station B sends the above-mentioned encrypted data CK ′ to the “call setting” message for the second mobile station b.
And make a call. The second mobile station b receives the “call setup” message from the second master unit B, acquires data included in the message (Get (CK ′)),
The encrypted data CK ′ is decrypted using the third secret key KBb to obtain the ID of the first mobile station a and the first secret key Kab ((a, Kab) = DKBb (CK ′)). Also, the second
The mobile station b sends a “call” message to the second base station B instead of immediately responding to the call from the second base station B, and then sends a “disconnect” message to the second base station B. Send and disconnect the call.

Next, the second mobile station b transmits a "call setup" message to the first mobile station a to make a call, and notifies completion of key distribution. In this case, it is desirable that the “call setting” message from the second mobile station b to the first mobile station a includes information indicating the completion of key distribution. The first mobile station a receives the “call setup” message from the second mobile station b, recognizes the completion of the key distribution, transmits a “disconnect” message to the second mobile station b, and disconnects the call. .

Thereafter, the first mobile station a transmits a "call setting" message to the second mobile station b to make a call. The second mobile station b that has received the “call setup” message has a caller ID
The first mobile station a that has requested encryption communication
After confirming that the message is the one of the first mobile station a, a "response" message is returned to the first mobile station a. Thereby, the first mobile station a
A call is established between the mobile station and the second mobile station b, and encryption communication (private communication) using the first secret key Kab is started between the two.

In the above description, the first mobile station a and the first mobile station a
In the encrypted communication path using the second secret key KAa with the master A, only the first secret key Kab is encrypted in the delivery data, but the present invention is not limited to this. For example,
The number of the second base station B notified from the second mobile station b, the ID of the second mobile station b, and all data of the ID of the first mobile station a, or one or a plurality of data among them, 1 secret key K
The data may be encrypted and delivered together with the ab, and the security is higher. On the other hand, in the encrypted communication path using the third secret key KBb between the second mobile station b and the second master unit B,
In order to avoid revealing to the eavesdropper that the target of the encrypted communication is the first mobile station a, not only the first secret key Kab but also the ID of the first mobile station a is encrypted and delivered.
Even if only the first secret key Kab is encrypted, the first secret key Kab
The goal of delivering b safely can be achieved.

In the above description, at the start of key distribution, both the first mobile station a and the first base unit A
It is assumed that you do not know the number. Therefore, in the above, the communication operation of the number request / response of the second base station B is performed between the first mobile station a and the second mobile station b (and in FIG. 12), and the first mobile station a The number of the second master unit B has been acquired. However, before the start of key distribution, at least one of the first mobile station a and the first master unit A can recognize the number of the second master station B (for example, if the number of the second master station B is registered in advance). ), The number request / response operation between the first mobile station a and the second mobile station b can be omitted.

As described above, in the secret key distribution system according to the present embodiment, the first secret key Kab used for the cryptographic communication between the first mobile station a and the second mobile station b is transmitted to the first mobile station. (a) using a second secret key KAa shared with the first master unit A in which the first mobile station a is registered. And a first encryption unit (first encryption unit 23 in FIG. 13) for encrypting data including at least the first secret key Kab. Mobile station b
A first mobile station a that sends a first delivery request to the first base station A for delivery to the second mobile station b via the second base station B in which the mobile station is registered, and (ii) a first mobile station. A first decryption unit (first decryption unit 27 in FIG. 14) for decrypting the encrypted data received from the station a using the second secret key KAa;
In response to the first delivery request from the first mobile station a, a second delivery request for delivering the first secret key Kab to the second mobile station b is sent together with the first secret key Kab to the wired communication network (ISDN).
(1) a first master unit A transmitting to the second master unit B via (1);
i) A second encryption unit (the second encryption unit 30 in FIG. 15) that encrypts data including at least the first secret key Kab using the third secret key KBb shared with the second mobile station b. ), The second master B transmitting the encrypted data to the second mobile station b in response to the second delivery request from the first master A, and (iv) the second master. And a second mobile station b having second decryption means (second decryption unit 33 in FIG. 16) for decrypting the encrypted data received from B using the third secret key KBb. It is.

Accordingly, the first mobile station a and the second mobile station b
And the unsecured radio section included between
In the section between the first mobile station a and the public base station 2a and the section between the second mobile station b and the public base station 2b), the delivery of the first secret key Kab can be performed safely.

In the above configuration, the first mobile station a
Means for transmitting to the second mobile station b a number notification request for notifying the first mobile station a of the number of the second master unit B in which the second mobile station b is registered (the number notification of FIG. 13). Request part 2
4), and the second mobile station b notifies the first mobile station a of the number of the second base unit A in response to the number notification request (the base unit number notification unit 36 in FIG. 16). ), The first mobile station a is configured to receive the notification of the number of the second base station B from the second mobile station b and transmit the first delivery request to the first base station A. . Thereby, the key first mobile station a
Even if the first master unit A does not know the number of the second master unit B before delivery, the above key delivery becomes possible.

Also, in the above configuration, the first secret key K
ab together with the ID of the first mobile station a
The data is transmitted from the first mobile station a to the second mobile station b via B, and the second mobile station b requests encryption communication based on the ID of the first mobile station a at the time of an incoming call. By determining whether or not the mobile station is a mobile station, higher security can be ensured. Also, as described above, the first secret key K
ab and the identification information (the ID of the mobile station a) of the encrypted communication requesting side are paired and delivered to the encrypted communication responding side.
The second mobile station b on the cryptographic communication response side can reliably determine with which mobile station the received first secret key Kab is a secret key for performing cryptographic communication.

In the above description, as an example in which the first mobile station a and the first master unit A can perform key distribution without knowing the number of the second master unit B before key distribution, the first mobile station a The method of directly exchanging the number of the second master unit B between the first mobile station b and the second mobile station b (in FIG. 12) has been described. In this case, as is clear from FIG. 12, although the functions required for the first and second mobile stations a and b are slightly increased, the first and second base units A and B in which each mobile station is registered are described. There is an advantage that the function is small and the load is light.

In the following third to sixth embodiments, a system for securely distributing the first secret key Kab from the first mobile station a to the second mobile station b via the first and second base units A and B. In the following, another method will be described in which the first mobile station a and the first master unit A can perform key distribution without knowing the number of the second master unit B before key distribution.

[Embodiment 3] Still another embodiment of the present invention is described below with reference to FIGS.

The system configuration according to the present embodiment is shown in FIG.
Is shown in First mobile station a of the secret key distribution system
As shown in FIG. 21, instead of the number notification request unit 24 and the first delivery request unit 25 in the first mobile station a of the second embodiment (see FIG. 13), the number notification request unit 324 and the first This is a configuration including a delivery request unit 325, and the other basic configuration is the same as that of the first mobile station a in the second embodiment. The number notification request unit 324 of the present embodiment
It has a function of transmitting a “number notification request for notifying the first base unit A of the number of the second base unit B in which the second mobile station b is registered” to the mobile station b. Further, the first delivery request unit 325 of the present embodiment assigns the number of the second master unit B to the first
The first delivery request for asking the first master A to send the pair of the ID of the first mobile station a and the first secret key Kab to the second mobile station b without sending it to the second mobile station b. "Is transmitted.

The first master unit A of the secret key distribution system
As shown in FIG. 22, a configuration is provided in which a second delivery request unit 328 is provided instead of the second delivery request unit 28 in the first parent machine A (see FIG. 14) of the second embodiment. ,
The other basic configuration is the same as that of the first master unit A of the second embodiment. The second delivery request unit 328 of the present embodiment
Upon receiving the first delivery request from the mobile station a and the notification of the number of the second base station B from the second mobile station b, the second base station B is notified of “the ID of the first mobile station a and the first A second delivery request requesting delivery of the pair (a, Kab) with the secret key Kab to the second mobile station b.

The second master unit B of the secret key distribution system
Has the same configuration as that of the second master unit B (see FIG. 15) of the second embodiment, and a description thereof will be omitted.

Further, as shown in FIG. 23, the second mobile station b of this secret key distribution system is provided in place of the parent device number notifying section 36 in the second mobile station b of the second embodiment (see FIG. 16). In addition, the mobile terminal has a configuration including a parent device number notification unit 336, and the other basic configuration is the same as that of the second mobile station b of the second embodiment. Base unit number notification unit 336 of the present embodiment
Has a function of receiving a number notification request from the first mobile station a and notifying the first master A of the number of the second master B.

Next, the basic operation of the secret key distribution system will be described mainly with reference to FIG.

First, the first mobile station a generates and holds the first secret key Kab for encrypted communication with the second mobile station b by the first secret key generation / holding unit 21 of FIG. 20), the first encryption key 23 of FIG.
b is encrypted to obtain CK (FIG. 20). And
The first mobile station a requests the second mobile station b to notify the first base station A of the number of the second base station B by the number notification request section 324 of FIG. 21 (see FIG. 20). Number request). The above number request may be made before the above key generation / encryption operation.

Further, the first mobile station a sends the ID of the second mobile station b and the ID of the first mobile station a to the first master unit A by the first delivery request unit 325 in FIG. Data (b, (a,) including a pair (a, CK) with the encrypted data CK
CK)) (FIG. 20) and (a, CK) to the second mobile station b.
Delivery request).

On the other hand, in response to the number notification request from the first mobile station a, the second mobile station b responds to the number notification of the base unit 33 shown in FIG.
6, the number of the second master unit B is notified to the first master unit A (number response in FIG. 20).

From the first mobile station a to (b, (a, C)
K)) and the second base station B from the second mobile station b
First, the first master unit A that has received the
The decryption unit 27 decrypts the encrypted data CK to obtain a first secret key Kab (FIG. 20). Then, the first parent machine A is operated by the second delivery request section 328 in FIG.
In order to request delivery of (a, Kab) to the second mobile station b, (b, (a, Kab)) is sent to the second master unit B (FIG. 20).

From the first master unit A, (b, (a, Ka)
b)) receives the (a, Ka) using the third secret key KBb by the second encryption unit 30 of FIG.
b) is encrypted to obtain CK '(FIG. 20). Then, the second master unit B distributes the encrypted data CK ′ to the second mobile station b by the distribution unit 31 of FIG. 15 (FIG. 20).

The second mobile station b having received the above-mentioned encrypted data CK 'is transmitted to the second mobile station b by the second decryption unit 33 of FIG.
To obtain (a, Kab) ((10) in FIG. 20),
The obtained ID of the first mobile station a and the first secret key Kab are
The encrypted communication information holding unit 34 shown in FIG. 23 holds the information and waits for the start of the encrypted communication with the first mobile station a. Then, the second mobile station b
Confirms the identification information (ID or number) of the other party at the time of the incoming call, and starts the encrypted communication using the first secret key Kab if the other party is the first mobile station a requesting the encrypted communication. ((11) in FIG. 20).

Next, a case where a call transfer service is used will be described as an example of a communication sequence of the secret key distribution system with reference to FIG.

First, the first mobile station a sets the first secret key Kab.
Is generated (make (Kab)), and the encrypted data CK is calculated using the second secret key KAa (CK = EKAa).
(Kab)).

Further, the first mobile station a, in the “call setup” message to the second mobile station b, sends a number notification request of the second base station B to the first base station A and the number of the first base station A. And the second
Place a call to mobile station b. The second mobile station b performs the “call setting”
If the message is received and the number of the first base unit A is obtained (Get (A)), a "call" message is returned to the first mobile station a.

Note that the second mobile station b can also acquire the ID of the first mobile station a upon receiving the above-mentioned “call setup” message from the first mobile station a (Get (a,
A)).

The first mobile station “a” receives the “call” message from the second mobile station “b”, and
It recognizes that the number notification request has been completed, and transmits a “disconnect” message to the second mobile station b to disconnect the call.

Thereafter, the first mobile station “a” transmits the ID of the second mobile station “b” in the “call setup” message to the first master unit A.
A call is made to the first base station A including the ID of the first mobile station a and the encrypted data CK.

The first master unit A receives the "call setup" message from the first mobile station a, acquires the data contained in the message (Get (b, a, CK)), and acquires the data therein. To obtain the first secret key Kab (Kab = DKAa (CK)). Note that the above-described decryption by the first master unit A may be performed within a period from acquisition of CK to calling of the second master unit B thereafter. Also, the first
Master A returns a "response" message to the incoming call from first mobile station a to establish a call, requests call transfer service (CT) from ISDN 1, and makes a call to mobile station a. On hold.

On the other hand, the second mobile station b is connected to the first mobile station a.
In response to the number notification request from, a call is made to the first master unit A including the number of the second master unit B in the "call setting" message. First
Master device A receives the “call setting” message from second mobile station b and acquires the number of second master device B (Get)
(B)), a "call" message is returned to the second mobile station b.
The second mobile station b recognizes that the number notification has been completed by receiving the “calling” message from the first master unit A, and transmits a “disconnect” message to the first master unit A to call. Disconnect.

Next, the first master unit A includes the ID of the second mobile station b, the ID of the first mobile station a, and the first secret key Kab in the “call setup” message for the second master unit B. , And calls the second master unit B. The second master unit B receives the “call setting” message from the first master unit A, acquires the data included in the message (Get (b, a, Kab)), and acquires the first data therein. The ID of the mobile station a and the first secret key Kab are encrypted using the third secret key KBb to obtain CK '(CK').
= EKBb (a, Kab)). The above-mentioned signaling by the second master unit B may be performed within a period from the acquisition of (b, a, Kab) to the subsequent call to the second mobile station b.
Further, the second master unit B returns a "response" message to the incoming call from the first master unit A.

When the first master unit A receives the "response" message from the second master unit B and the call with the second master unit B is established, the first master unit A requests the ISDN 1 for call transfer, and
The call to the mobile station a is transferred to the second master unit B. This allows
When a call is established between the first mobile station a and the second base station B, the second base station B requests a call transfer from the ISDN 1 and suspends the call with the first mobile station a. A call is made with the above-mentioned encrypted data CK 'included in the "call setting" message for the second mobile station b.

The second mobile station b receives the “call setup” message from the second base station B, acquires the encrypted data CK ′ (Get (CK ′)), and decrypts it with the third secret key KBb. To obtain the ID of the first mobile station a and the first secret key Kab ((a, Kab) = DKBb (CK ')). Further, the second mobile station b returns a "response" message to the second base station B and connects the channel, and then waits for the start of cryptographic communication with the first mobile station a.

Upon receiving the "response" message from second mobile station b, second base station B requests ISDN 1 for a call transfer, and transfers the call with first mobile station a to second mobile station b. . As a result, a call between the first mobile station a and the second mobile station b is established, and encryption communication (private communication) using the first secret key Kab is started between the two.

In the case of the secret key distribution system, as in the second embodiment, a form in which the call transfer service is not used is considered (when two calls can be held at the same time, and when one call is made). If you can only have any). Since the basic sequence in the mode not using the call transfer service has been described in the second embodiment, the description is omitted.

As described above, in the secret key distribution system according to the present embodiment, the first secret key Kab used for the cryptographic communication between the first mobile station a and the second mobile station b is transmitted to the first mobile station. (a) using a second secret key KAa shared with the first master unit A in which the first mobile station a is registered. And a first encryption unit (first encryption unit 23 in FIG. 21) for encrypting data including at least the first secret key Kab. Mobile station b
A first delivery request for delivery to the first base unit A is sent to the second base station B in which the second mobile station b is registered.
A first mobile station a transmitting a number notification request for notifying the first base station A of the number to the second mobile station b; and (ii) encrypting the encrypted data received from the first mobile station a. 2 has a first decryption means (the first decryption unit 27 in FIG. 22) for decrypting using the secret key KAa, and a first delivery request from the first mobile station a and a first delivery request from the second mobile station b. In response to the notification of the number of the two base units B, a second delivery request for delivering the first secret key Kab to the second mobile station b together with the first secret key Kab is sent via the wired communication network (ISDN1). (Iii) at least a first secret key Kab using the third secret key KBb shared between the first master device A to be transmitted to the second master device B and (iii) the second mobile station b.
The second encryption unit (the second encryption unit 30 in FIG. 15) for encrypting the data including the character string, and in response to the second delivery request from the first master unit A, encrypts the encrypted data. A second base station B to be transmitted to the second mobile station b; and (iv) second decoding means for decoding the encrypted data received from the second base station B using a third secret key KBb (FIG. 23 second decoding unit 33)
And a second mobile station b that notifies the first base unit A of the number of the second base unit B in response to a number notification request from the first mobile station a.

Thus, the first mobile station a and the second mobile station b
And the unsecured radio section included between
In the section between the first mobile station a and the public base station 2a and the section between the second mobile station b and the public base station 2b), the delivery of the first secret key Kab can be performed safely.

In the secret key distribution system according to the present embodiment, as is apparent from FIG. 20, the first mobile station a and the first master unit A in which the first mobile station a is registered are located on the encrypted communication request side.
The functions are shared by and the load of both is equalized. On the other hand, on the cryptographic communication response side, the functions required of the second mobile station b are slightly increased, and the functions of the second base station B are few and the load is light.

[Embodiment 4] Still another embodiment of the present invention will be described below with reference to FIGS.

The system configuration according to the present embodiment is shown in FIG.
Is shown in First mobile station a of the secret key distribution system
26, as shown in FIG. 26, is a configuration in which the number notification request unit 24 in the first mobile station a (see FIG. 21) of the third embodiment is omitted, and the other basic configuration is the third embodiment.
Of the first mobile station a.

The first master unit A of the secret key distribution system
As shown in FIG. 27, in the first master unit A of the third embodiment (see FIG. 22), the number notification request unit 42
4 and the other basic configuration is the same as that of the first master unit A of the third embodiment. In response to the first delivery request from the first mobile station a, the number notification request unit 424 of the present embodiment sends the second mobile station b
Is transmitted to the first base unit A to notify the first base unit A of the registered number of the second base unit B.

Also, the second master unit B of the secret key distribution system
Has the same configuration as the second parent machine B (see FIG. 15) of the second and third embodiments, and a description thereof will be omitted.

Further, as shown in FIG. 23, the second mobile station b of the present secret key distribution system replaces the parent machine number notifying section 336 in the second mobile station b of the third embodiment (see FIG. 23). In addition, the base station number notification unit 436 is provided, and the other basic configuration is the same as that of the second mobile station b of the third embodiment. Base unit number notification unit 436 of the present embodiment
Receives the number notification request from the first master unit A,
Has the function of notifying the number of the second master unit B to the user.

Next, the basic operation of the secret key distribution system will be described mainly with reference to FIG.

First, the first mobile station a generates and holds the first secret key Kab for encrypted communication with the second mobile station b by the first secret key generation / holding unit 21 of FIG. 25), the first encryption key 23 of FIG.
b is encrypted to obtain CK (FIG. 25). further,
The first mobile station a sends the ID of the second mobile station b, the ID of the first mobile station a, and the encrypted data CK to the first base unit A by the first delivery request unit 325 in FIG. (B, (a, CK)) including the pair (a, CK) of FIG. 25 (FIG. 25) and (a, CK) to the second mobile station b. (First delivery request).

[0206] In response to the first delivery request from the first mobile station a, the first base station A sends the second base station B to the second mobile station b by the number notification request section 424 in FIG. A request is made to notify the first master unit A of the number (number request in FIG. 25). The second mobile station b responds to the number notification request from the first master unit A by the master unit number notification unit 436 of FIG.
The main unit A is notified of the number of the second main unit B (number response in FIG. 25).

From the first mobile station a, (b, (a, C)
K)) and the second base station B from the second mobile station b
The first master unit A, which has received the
The decryption unit 27 decrypts the encrypted data CK to obtain a first secret key Kab (FIG. 25). Then, the first master unit A uses the second delivery request unit 328 in FIG.
(B, (a, Kab)) is sent to the second master unit B in order to request delivery of (a, Kab) to the second mobile station b (FIG. 50).

From the first master unit A, (b, (a, Ka)
b)) receives the (a, Ka) using the third secret key KBb by the second encryption unit 30 of FIG.
b) is encrypted to obtain CK ′ (FIG. 25). Then, the second master unit B distributes the encrypted data CK ′ to the second mobile station b by the distribution unit 31 of FIG. 15 (FIG. 25).

The second mobile station b having received the above-mentioned encrypted data CK 'is transmitted to the second mobile station b by the second decryption unit 33 shown in FIG.
To obtain (a, Kab) ((10) in FIG. 25),
The obtained ID of the first mobile station a and the first secret key Kab are
It is held in the encrypted communication information holding unit 34 in FIG. 28 and waits for the start of the encrypted communication with the first mobile station a. Then, the second mobile station b
Confirms the identification information (ID or number) of the other party at the time of the incoming call, and starts the encrypted communication using the first secret key Kab if the other party is the first mobile station a requesting the encrypted communication. ((11) in FIG. 25).

Next, a case where a call transfer service is used will be described as an example of a communication sequence of the secret key distribution system with reference to FIG.

First, the first mobile station a sets the first secret key Kab.
Is generated (make (Kab)), and the encrypted data CK is calculated using the second secret key KAa (CK = EKAa).
(Kab)). Thereafter, the first mobile station a sends the I of the second mobile station b in the “call setup” message to the first base station A.
A call is made to the first master unit A, including D, the ID of the first mobile station a, and the encrypted data CK.

The first master unit A receives the “call setup” message from the first mobile station a, acquires the data contained in the message (Get (b, a, CK)), and To obtain the first secret key Kab (Kab = DKAa (CK)). Note that the above-described decryption by the first master unit A may be performed within a period from acquisition of CK to calling of the second master unit B thereafter. Also, the first
Master A returns a "response" message to the incoming call from first mobile station a to establish a call, requests call transfer service (CT) from ISDN 1, and makes a call to mobile station a. On hold.

[0213] Next, the first master unit A includes the "call setup" message for the second mobile station b, including a request to notify the first master unit A of the number of the second master unit B. Call b. If the second mobile station b receives the "call setup" message and obtains the number of the first master unit A (Get (A)), the "call" message including the number of the second master unit B is obtained. To the first master unit A
Reply to The first master unit A receives the "call" message and acquires the number of the second master unit B (Get (B)), and thereafter sends a "disconnect" message to the second mobile station b to disconnect the call. . Thereafter, the second mobile station b waits until there is a call from the second base station B.

Next, the first master unit A includes the ID of the second mobile station b, the ID of the first mobile station a, and the first secret key Kab in the “call setting” message for the second master unit B. , And calls the second master unit B. The second master unit B receives the “call setting” message from the first master unit A, acquires the data included in the message (Get (b, a, Kab)), and acquires the first data therein. The ID of the mobile station a and the first secret key Kab are encrypted using the third secret key KBb to obtain CK '(CK').
= EKBb (a, Kab)). The above-mentioned signaling by the second master unit B may be performed within a period from the acquisition of (b, a, Kab) to the subsequent call to the second mobile station b.
Further, the second master unit B returns a "response" message to the incoming call from the first master unit A.

When the first master unit A receives the "response" message from the second master unit B and the call with the second master unit B is established, the first master unit A requests the ISDN 1 for a call transfer, and
The call to the mobile station a is transferred to the second master unit B. This allows
When a call is established between the first mobile station a and the second base station B, the second base station B requests a call transfer from the ISDN 1 and suspends the call with the first mobile station a. A call is made with the above-mentioned encrypted data CK 'included in the "call setting" message for the second mobile station b.

The second mobile station b receives the “call setup” message from the second master unit B, acquires the encrypted data CK ′ (Get (CK ′)), and decrypts it with the third secret key KBb. To obtain the ID of the first mobile station a and the first secret key Kab ((a, Kab) = DKBb (CK ')). Further, the second mobile station b returns a "response" message to the second base station B and connects the channel, and then waits for the start of cryptographic communication with the first mobile station a.

Upon receiving the "response" message from second mobile station b, second base station B requests ISDN 1 for a call transfer, and transfers the call with first mobile station a to second mobile station b. . As a result, a call between the first mobile station a and the second mobile station b is established, and encryption communication (private communication) using the first secret key Kab is started between the two.

In the present private key distribution system, as in the above-described second embodiment, a form in which the call transfer service is not used is conceivable. (Either case where only one is possible is possible.)

As described above, in the secret key distribution system according to the present embodiment, the first secret key Kab used for the cryptographic communication between the first mobile station a and the second mobile station b is transmitted to the first mobile station. (a) using a second secret key KAa shared with the first master unit A in which the first mobile station a is registered. 26, a first encryption unit (the first encryption unit 23 in FIG. 26) for encrypting data including at least the first secret key Kab. Mobile station b
The first mobile station a transmitting a first delivery request for delivery to the first base station A, and (ii) the encrypted data received from the first mobile station a using the second secret key KAa. A first decoding unit (first decoding unit 27 in FIG. 27) for decoding, and a second mobile station b is registered in response to a first delivery request from the first mobile station a. A number notification request for notifying the first master unit A of the number of the second master unit B is transmitted to the second mobile station b, and the number notification of the second master station B is received from the second mobile station b. Transmitting a second delivery request for delivering the first secret key Kab to the second mobile station b together with the first secret key Kab to the second base unit B via the wired communication network (ISDN1). The data including at least the first secret key Kab using the third secret key KBb shared between the master unit A and (iii) the second mobile station b. The second encryption unit (the second encryption unit 30 in FIG. 15) for encrypting the encrypted data in accordance with the second delivery request from the first master unit A. A second base station B transmitting to the station b, and (iv) a second base station B
And a second decryption unit (the second decryption unit 33 in FIG. 28) for decrypting the encrypted data received from the first master unit A using the third secret key KBb. And a second mobile station b for notifying the first base unit A of the number of the second base unit B in response to a request.

Thus, the first mobile station a and the second mobile station b
And the unsecured radio section included between
In the section between the first mobile station a and the public base station 2a and the section between the second mobile station b and the public base station 2b), the delivery of the first secret key Kab can be performed safely.

In the secret key distribution system according to the present embodiment, as is apparent from FIG. 25, the function of the first mobile station a is reduced and the load is reduced on the encrypted communication requesting side, and it is registered. The functions required of the first master unit A are slightly increased. On the other hand, on the cryptographic communication response side, the functions required of the second mobile station b are slightly increased, and the functions of the second base station B are few and the load is light.

[Fifth Embodiment] The following will describe still another embodiment of the present invention with reference to FIGS.

FIG. 30 shows a system configuration according to this embodiment.
Is shown in First mobile station a of the secret key distribution system
Has the same configuration as the first mobile station a (see FIG. 21) of the third embodiment, and a description thereof will be omitted. The number notification request transmitted by the number notification request unit 324 in FIG. 21 to the second mobile station b is a first number notification request.

Also, the first master unit A of the secret key distribution system
As shown in FIG. 31, the fourth embodiment has a configuration in which a fourth delivery request unit 501 is provided instead of the second delivery request unit 28 in the first master unit A (see FIG. 14) of the second embodiment. ,
The other basic configuration is the same as that of the first master unit A of the second embodiment. The fourth delivery request unit 501 of the present embodiment
The first delivery request from the mobile station a and the second mobile station b
Receives the number of the second base unit B and a third delivery request, which will be described later, and sends the ID of the first mobile station a and the first
And a function of transmitting a “fourth delivery request for requesting delivery of the pair (a, Kab) with the secret key Kab” to the second mobile station b.

Further, the second master unit B of the secret key distribution system
As shown in FIG. 32, the second base unit B according to the second embodiment (see FIG. 15) further includes a number notification unit 502 and a third delivery request unit 503. The basic configuration is the same as that of the first master unit A of the second embodiment. The number notifying unit 502 of the present embodiment has a function of notifying the first master unit A of the number of the second master unit B in response to a second number notification request from the second mobile station b described later. In addition, the third delivery requesting unit 503 of the present embodiment responds to the second delivery request from the second mobile station b, as follows: “The first secret key Kab is transmitted to the second mobile station via the second base unit B. b) to the first master unit A.

Further, as shown in FIG. 33, the second mobile station b of this secret key distribution system is provided in place of the parent device number notifying section 36 in the second mobile station b of the second embodiment (see FIG. 16). In addition, a second number notification request unit 504 and a second delivery request unit 505 are provided, and other basic configurations are the same as those of the second mobile station b of the second embodiment. In response to the first number notification request from the first mobile station a, the second number notification requesting unit 504 of the present embodiment sets the “second number request for notifying the number of the second base station B to the first base station A”. And a function of transmitting a "2 number notification request" to the second master unit B. Further, in response to the first number notification request from the first mobile station a, the second delivery requesting unit 505 of the present embodiment sets the “second delivery request for delivering the first secret key Kab to the second mobile station b”. Delivery request ”for the second master unit B
It has the function of sending to

Next, the basic operation of the secret key distribution system will be described mainly with reference to FIG.

First, the first mobile station a generates and holds the first secret key Kab for encrypted communication with the second mobile station b by the first secret key generation / holding unit 21 of FIG. 30), the first encryption key 23 of FIG.
b is encrypted to obtain CK (FIG. 30). And
The first mobile station a requests the second mobile station b to notify the first base station A of the number of the second base station B by the number notification request section 324 of FIG. Request) (number request in FIG. 30). The above number request may be made before the above key generation / encryption operation.

Further, the first mobile station a sends the ID of the second mobile station b and the ID of the first mobile station a to the first master unit A by the first delivery request unit 325 in FIG. Data (b, (a,) including a pair (a, CK) with the encrypted data CK
CK)) (FIG. 30) and request the first master unit A to deliver (a, CK) to the second mobile station b (first
Delivery request).

From the first mobile station a, (b, (a, C)
K)), the first master unit A decrypts the encrypted data CK by the first decryption unit 27 in FIG. 31 to obtain a first secret key Kab (FIG. 30).

On the other hand, in response to the first number notification request from the first mobile station a, the second mobile station b uses the second number notification request unit 504 and the second delivery request unit 505 in FIG. Requesting device B to notify first master device A of the number of second master device B (second number notification request), and delivering first secret key Kab to second mobile station b (Second delivery request) (FIG. 30).

In response to the second number notification request and the second delivery request from the second mobile station b, the second master unit B uses the number notification unit 502 and the third delivery request unit 503 in FIG. Notify the device A of the number of the second master device B and the ID of the second mobile station b, and request that the first secret key Kab be delivered to the second mobile station b via the second master device B. (Third delivery request) (FIG. 30).

The first master unit A sends the first delivery request from the first mobile station a, and the notification of the number of the second master station B and the ID of the second mobile station b from the second master station B ( Number response and the third delivery request), and the fourth delivery request unit 501 in FIG.
To request (a fourth delivery request) to deliver (a, Kab) to the second mobile station b, (b,
(A, Kab)) (FIG. 30).

From the first master unit A, (b, (a, Ka)
b)) receives the (a, Ka) using the third secret key KBb by the second encryption unit 30 of FIG. 32.
b) is encrypted to obtain CK '(FIG. 30). Then, the second master unit B distributes the encrypted data CK ′ to the second mobile station b by the distribution unit 31 of FIG. 32 (see FIG. 30).
(Ten)).

The second mobile station b having received the above-described encrypted data CK 'is transmitted to the second mobile station b by the second decryption unit 33 in FIG.
To obtain (a, Kab) ((11) in FIG. 30),
The obtained ID of the first mobile station a and the first secret key Kab are
The encrypted communication information is held in the encrypted communication information holding unit 34 in FIG. Then, the second mobile station b
Confirms the identification information (ID or number) of the other party at the time of the incoming call, and starts the encrypted communication using the first secret key Kab if the other party is the first mobile station a requesting the encrypted communication. ((12) in FIG. 30).

Next, a case where a call transfer service is used will be described with reference to FIG. 34 as an example of a communication sequence of the above-described secret key distribution system.

First, the first mobile station a sets the first secret key Kab.
Is generated (make (Kab)), and the encrypted data CK is calculated using the second secret key KAa (CK = EKAa).
(Kab)).

Further, the first mobile station a includes the above-mentioned first number notification request and the number of the first master unit A in the “call setup” message for the second mobile station b, Make a call to. When the second mobile station b receives the “call setup” message and acquires the number of the first master unit A (Get (A)),
A "call" message is returned to the first mobile station a.

The second mobile station b can also acquire the ID of the first mobile station a at the time of receiving the above-mentioned “call setup” message from the first mobile station a (Get (a,
A)).

The first mobile station a receives the “call” message from the second mobile station b, and
Recognizing that the first number notification request has been completed, transmits a "disconnect" message to the second mobile station b, and disconnects the call.

Thereafter, the first mobile station “a” transmits the ID of the second mobile station “b” in the “call setup” message to the first master unit A.
A call is made to the first base station A including the ID of the first mobile station a and the encrypted data CK.

The first master unit A receives the "call setup" message from the first mobile station a, acquires the data contained in the message (Get (b, a, CK)), and acquires the data therein. To obtain the first secret key Kab (Kab = DKAa (CK)). Also, the first master unit A
Returns a "response" message to the incoming call from the first mobile station a and establishes the call.
Requests service (CT) to ISDN 1 and suspends the call with mobile station a.

On the other hand, the second mobile station b is connected to the first mobile station a.
In response to the first number notification request from the second mobile station b, the "call setup" message includes the number of the first base station A and the ID of the second mobile station b (second number notification request and second delivery request). Calls machine B. Upon receiving the “call setting” message from the second mobile station b, the second base station B acquires the number of the first base station A and the ID of the second mobile station b (Get (b, A) ), Return a "call" message to the second mobile station b. The second mobile station b
By receiving the "calling" message from master B, it recognizes that the second number notification request and the second delivery request have been completed, and transmits a "disconnect" message to second master B to initiate the call. Disconnect.

Next, the second master unit B includes the ID of the second mobile station b and the number of the second master station B (number response and third delivery request) in the “call setup” message, Calls machine A. The first master unit A receives the “call setting” message from the second master unit B, acquires the data included in the message (Get (b, B)), and acquires the data in the “response” message. (2) The call including the ID of the mobile station b, the ID of the first mobile station a, and the first secret key Kab is returned to the second base station B to establish a call. The second master unit B receives the “response” message from the first master unit A, acquires the data included in the message (Get (b, a, Kab)), and performs the first move in the data. The ID of the station a and the first secret key Kab are encrypted using the third secret key KBb to obtain CK ′ (CK ′ = EKBb)
(A, Kab)).

Further, first master unit A requests ISDN 1 for call transfer, and transfers the call with first mobile station a to second master unit B. Thereby, the first mobile station a and the second base station B
When the call is established between the second base unit B and the
Requests call transfer to N1, suspends the call with the first mobile station a, and then “call setup” for the second mobile station b
A call is made with the above-mentioned encrypted data CK 'included in the message.

The second mobile station b receives the “call setup” message from the second base station B, acquires the encrypted data CK ′ (Get (CK ′)), and decrypts it with the third secret key KBb. To obtain the ID of the first mobile station a and the first secret key Kab ((a, Kab) = DKBb (CK ')). Further, the second mobile station b returns a "response" message to the second base station B and connects the channel, and then waits for the start of cryptographic communication with the first mobile station a.

Upon receiving the "response" message from second mobile station b, second base station B requests ISDN 1 for call transfer, and transfers the call to first mobile station a to second mobile station b. . As a result, a call between the first mobile station a and the second mobile station b is established, and encryption communication (private communication) using the first secret key Kab is started between the two.

In the present secret key distribution system, as in the second embodiment, a form in which the call transfer service is not used can be considered (when two calls can be held at the same time, and when one call is made). (Either case where only one is possible is possible.)

As described above, in the secret key distribution system according to the present embodiment, the first secret key Kab used for the cryptographic communication between the first mobile station a and the second mobile station b is transmitted to the first mobile station. 1. A secret key delivery system for delivering from a.a to a second mobile station b, using (i) a second secret key KAa shared with the first base unit A in which the first mobile station a is registered. And a first encryption unit (the first encryption unit 23 in FIG. 21) for encrypting data including at least the first secret key Kab. Mobile station b
A first delivery request for delivery to the first base unit A is sent to the second base station B in which the second mobile station b is registered.
A first mobile station a transmitting a first number notification request to notify the first base unit A of the first number to the second mobile station b;
i) the encrypted data received from the first mobile station a
First decryption means (FIG. 3) for decrypting using the secret key KAa
1), a first delivery request from the first mobile station a, a number of the second base unit B from the second base station B, a third delivery request described below, and a second transfer request. Upon receiving the notification of the communication number of the second master unit from the station, it requests the delivery of the first secret key Kab to the second mobile station b together with the first secret key Kab decrypted by the first decryption means. The first parent machine A transmitting the fourth delivery request to the second parent machine B via the wired communication network (ISDN1) and (iii) the third secret key KBb shared between the second mobile station b and A second encryption unit (second encryption unit 30 in FIG. 32) for encrypting data including at least the first secret key Kab using the second mobile station B and the following second number notification request. Distributing the first secret key Kab together with the number of the second parent device B to the second mobile station b via the second parent device B in response to the second distribution request Is transmitted to the first master unit A, and in response to the fourth delivery request from the first master unit A, the data encrypted by the second encryption unit is transmitted to the second mobile station B. And (iv) second decryption means for decrypting the encrypted data received from the second parent device B using the third secret key KBb (the second decryption device shown in FIG. 33). Transformation part 3
3), and in addition to the second number notification request for notifying the first base unit A of the number of the second base unit B in response to the first number notification request from the first mobile station a, the first Secret key K
and a second mobile station b for transmitting a second delivery request for delivering ab to the second mobile station b to the second base unit B.

Accordingly, the first mobile station a and the second mobile station b
And the unsecured radio section included between
In the section between the first mobile station a and the public base station 2a and the section between the second mobile station b and the public base station 2b), the delivery of the first secret key Kab can be performed safely.

In the secret key distribution system of the present embodiment, as is apparent from FIG. 30, the first mobile station a and the first master unit A in which the mobile station a is registered are located on the encrypted communication request side.
The functions are shared by and the load of both is equalized. Also, on the encryption communication response side, the load is equalized between the second mobile station b and the second master unit B in which the second mobile station b is registered. However, the load on the encrypted communication request side is lighter than the load on the encrypted communication response side.

[Embodiment 6] The following will describe still another embodiment of the present invention with reference to FIGS.

FIG. 35 shows a system configuration according to the present embodiment.
Is shown in First mobile station a of the secret key distribution system
Has the same configuration as the first mobile station a (see FIG. 26) of the fourth embodiment, and a description thereof will be omitted.

Also, the first master unit A of the secret key distribution system
As shown in FIG. 36, in the first parent machine A of the fifth embodiment (see FIG. 31),
And the other basic configuration is the same as that of the first master unit A of the fifth embodiment. The number notification request sent by the number notification request unit 424 to the second mobile station b is a first number notification request.

Also, the second master unit B of the secret key distribution system
Has the same configuration as the second master unit B (see FIG. 32) of the fifth embodiment, and a description thereof will be omitted.

Further, as shown in FIG. 37, the second mobile station b of the secret key distribution system is provided with the second number notification requesting unit 50 in the second mobile station b of the fifth embodiment (see FIG. 33).
The second mobile station according to the fifth embodiment has a configuration including a second number notification requesting unit 604 and a second delivery requesting unit 605 instead of the fourth and second delivery requesting units 505. Same as b. In response to the first number notification request from the second base unit B, the second number notification request unit 604 of the present embodiment sets “the second base unit B's request to notify the first base unit A of the number. And a function of transmitting a "2 number notification request" to the second master unit B. Also, the second delivery request unit 605 of the present embodiment
Transmits a “second delivery request for delivering the first secret key Kab to the second mobile station b” to the second base station B in response to the first number notification request from the first base station A. Has functions.

Next, the basic operation of the secret key distribution system will be described mainly with reference to FIG.

First, the first mobile station a generates and holds the first secret key Kab for encrypted communication with the second mobile station b by the first secret key generation / holding unit 21 of FIG. 35), the first encryption key 23 of FIG.
b is encrypted to obtain CK (FIG. 35). further,
The first mobile station a sends the ID of the second mobile station b, the ID of the first mobile station a, and the encrypted data CK to the first base unit A by the first delivery request unit 325 in FIG. (B, (a, CK)) including the pair (a, CK) of the first base station A (FIG. 35), and (a, CK) to the second mobile station b. (First delivery request).

From the first mobile station a, (b, (a, C)
K)), the first master unit A decrypts the encrypted data CK by the first decryption unit 27 in FIG. 36 to obtain a first secret key Kab (FIG. 35). Further, the first master unit A responds to the first delivery request from the first mobile station a in FIG.
The number notification request unit 424 of No. 6 requests the second mobile station b to notify the number of the second master unit B to the first master unit A (first number notification request) (the number in FIG. 35). request).

In response to the first number notification request from the first master unit A, the second mobile station b uses the second number notification request unit 604 and the second delivery request unit 605 in FIG. Machine B
Requesting that the number of the second base unit B be notified to the first base unit A (second number notification request), and requesting that the first secret key Kab be delivered to the second mobile station b. (Second delivery request) (FIG. 35).

The second base station B responds to the second number notification request and the second delivery request from the second mobile station b by the number notification section 502 and the third delivery request section 503 in FIG. Notify the device A of the number of the second master device B and the ID of the second mobile station b, and request that the first secret key Kab be delivered to the second mobile station b via the second master device B. (Third delivery request) (FIG. 35).

The first base station A sends the first delivery request from the first mobile station a, and the second base station B number and the ID of the second mobile station b from the second base station B ( Number response and the third delivery request), and the fourth delivery request unit 501 in FIG.
To request (a fourth delivery request) to deliver (a, Kab) to the second mobile station b, (b,
(A, Kab)) (FIG. 35).

From the first master unit A, (b, (a, Ka)
b)) receives the (a, Ka) using the third secret key KBb by the second encryption unit 30 of FIG. 32.
b) is encrypted to obtain CK '(FIG. 35). Then, the second master unit B delivers the encrypted data CK ′ to the second mobile station b by the delivery unit 31 of FIG. 32 (see FIG. 35).
(Ten)).

The second mobile station b having received the above-described encrypted data CK 'is transmitted to the second mobile station b by the second decryption unit 33 in FIG.
To obtain (a, Kab) ((11) in FIG. 35),
The obtained ID of the first mobile station a and the first secret key Kab are
The encrypted communication information holding unit 34 shown in FIG. 37 holds the information and waits for the start of the encrypted communication with the first mobile station a. Then, the second mobile station b
Confirms the identification information (ID or number) of the other party at the time of the incoming call, and starts the encrypted communication using the first secret key Kab if the other party is the first mobile station a requesting the encrypted communication. ((12) in FIG. 35).

Next, a case where a call transfer service is used will be described as an example of a communication sequence of the secret key distribution system with reference to FIG.

First, the first mobile station a sets the first secret key Kab.
Is generated (make (Kab)), and the encrypted data CK is calculated using the second secret key KAa (CK = EKAa).
(Kab)). Thereafter, the first mobile station a sends the I of the second mobile station b in the “call setup” message to the first base station A.
A call is made to the first master unit A, including D, the ID of the first mobile station a, and the encrypted data CK.

The first master unit A receives the "call setup" message from the first mobile station a, acquires the data contained in the message (Get (b, a, CK)), and acquires the data therein. To obtain the first secret key Kab (Kab = DKAa (CK)). Also, the first master unit A
Returns a "response" message to the incoming call from the first mobile station a and establishes the call.
Requests service (CT) to ISDN 1 and suspends the call with mobile station a.

Next, the first master unit A makes a call to the second mobile station b, including the above-mentioned first number notification request in the "call setup" message for the second mobile station b. The second mobile station b receives the "call setup" message and acquires the number of the first master unit A (Get (A)). It should be noted that, during the “call setup” message that the first master unit A sends to the second mobile station b, the I
If D is included, the second mobile station b acquires the ID of the first mobile station a when receiving the “call setup” message (Get (a, A)).

Next, the second mobile station b communicates with the first master unit A
"Call" message in response to call from. The first master unit A recognizes that the first number request has been accepted by the second mobile station b by receiving the “call” message, and then sends a “disconnect” message to the second mobile station b. To disconnect the call.

In response to the first number notification request from the first mobile station a, the second mobile station b having received the above-mentioned "disconnection" message responds to the first call request message from the first mobile station a. And the ID of the second mobile station b (the second number notification request and the second delivery request) and make a call to the second base station B.

Since the subsequent communication sequence is the same as the sequence described in the fifth embodiment with reference to FIG. 34, description thereof will be omitted.

Also, in the case of the present secret key distribution system,
As in the second embodiment, a form in which the call transfer service is not used is conceivable (both cases where two calls can be held at the same time and cases where only one call can be held). I do.

As described above, in the secret key distribution system according to the present embodiment, the first secret key Kab used for the cryptographic communication between the first mobile station a and the second mobile station b is transmitted to the first mobile station. (a) using a second secret key KAa shared with the first master unit A in which the first mobile station a is registered. 26, a first encryption unit (the first encryption unit 23 in FIG. 26) for encrypting data including at least the first secret key Kab. Mobile station b
The first mobile station a transmitting a first delivery request for delivery to the first base station A, and (ii) the encrypted data received from the first mobile station a using the second secret key KAa. A first decoding unit (first decoding unit 27 in FIG. 36) for decoding, and a second mobile station b is registered in response to a first delivery request from the first mobile station a. Assign the number of master unit B to first master unit A
To the second mobile station b, and a first delivery request from the first mobile station a, the number of the second base station B from the second base station B In response to the third delivery request described below, a fourth delivery request for delivering the first secret key Kab to the second mobile station b is sent together with the first secret key Kab decrypted by the first decryption means via wired communication. Network (ISD
A first master unit A transmitting to the second master unit B via N1);
(Iii) Third secret key KB shared with second mobile station b
b using a second encryption unit (second encryption unit 3 in FIG. 32) that encrypts data including at least the first secret key Kab.
0), and in response to the following second number notification request and second delivery request from the second mobile station B, the first secret key Kab and the second secretary key B A third delivery request for delivery to the second mobile station b via the first base unit A, and in response to the fourth delivery request from the first base unit A, the second encryption unit. And (iv) decrypting the encrypted data received from the second base station B using the third secret key KBb. 2 decoding means (second decoding unit 33 in FIG. 37)
And a first secret key together with a second number notification request for notifying the first master unit A of the number of the second master unit B in response to the first number notification request from the first master unit A. And a second mobile station b for transmitting a second delivery request to deliver the Kab to the second mobile station b to the second base unit B.

Accordingly, the first mobile station a and the second mobile station b
And the unsecured radio section included between
In the section between the first mobile station a and the public base station 2a and the section between the second mobile station b and the public base station 2b), the delivery of the first secret key Kab can be performed safely.

In the secret key distribution system according to the present embodiment, as is apparent from FIG.
The load on the mobile station a is reduced, and the loads on the other first base unit A, second base unit B, and second mobile station b are equalized.

In each of the above-described first to sixth embodiments, an example in which ISDN1 is used as a wired communication network has been described. However, the present invention is not limited to this, and another wired communication network such as an analog telephone line may be used. Can also be used. In the case of an analog telephone line, various services such as ISDN1 (call transfer, user / user information transfer, etc.) cannot be used and two channels cannot be used at the same time. If the operation of disconnecting the call after the notification is repeated, the secret key distribution system according to each embodiment can be realized even if a wired communication network other than ISDN1 is used.

[0277]

As described above, according to the secret key distribution method of the present invention, the first secret key used for the cryptographic communication between the mobile station and the wired terminal performing the radio communication with the base station. To
A method for delivering from a mobile station to a wired terminal, wherein the mobile station and the base unit are shared by a preset second secret key shared between the mobile station and the base unit with which the mobile station is registered. Establishing a cryptographic communication path, and distributing the first secret key from the mobile station to the master unit via the cryptographic communication path; and transmitting the first secret key distributed from the mobile station to the master unit via the wired communication network. And delivering the first secret key via the parent device.

Therefore, the first secret key can be safely delivered between the insecure mobile station and the base station included in the first secret key delivery section without using an advanced encryption method such as a public key encryption method. , And high security can be ensured at the time of key distribution from the mobile station to the wired terminal.

[0279] The secret key distribution method according to the invention of claim 2 is as follows.
As described above, a method for delivering a first secret key used for encrypted communication between a mobile station performing wireless communication with a base station and a wired terminal from the wired terminal to the mobile station, the method comprising: Delivering the key from the wired terminal to the parent device in which the mobile station is registered via the wired communication network, and providing the mobile station with a preset second secret key shared between the mobile station and the parent device. Establishing a cryptographic communication path between the base station and the base station, and distributing the first secret key delivered from the wired terminal to the mobile station from the base station via the cryptographic communication path. First
This is a configuration for delivering a secret key.

Therefore, the first secret key can be safely distributed between the insecure mobile station and the base station included in the first secret key distribution section without using an advanced encryption method such as a public key encryption method. , And high security can be ensured at the time of key distribution from the wired terminal to the mobile station.

The secret key distribution method according to the third aspect of the present invention
As described above, the first secret key used for the encrypted communication between the first mobile station and the second mobile station that performs wireless communication with the base station is delivered from the first mobile station to the second mobile station. A method, comprising: a first mobile station and a first mobile station in which the first mobile station is registered.
An encrypted communication path between the first mobile station and the first base station is established by a preset second secret key shared with the base unit, and the first secret key is transmitted through the encrypted communication path. Delivering the first secret key delivered from the first mobile station to the second base station in which the second mobile station is registered, by delivering the first secret key delivered from the first mobile station to the second base station in which the second mobile station is registered; Via the second mobile station and the second base unit by using a preset third secret key shared between the second mobile station and the second base unit. Establishing and distributing the first secret key delivered from the first master unit to the second mobile station via the cryptographic communication path from the second master unit to the second mobile station via the first and second master units. In such a manner that the first secret key is delivered.

Therefore, without using an advanced encryption method such as a public key encryption method, it is possible to securely secure the first secret key between each unsecured mobile station and base station included in the delivery section of the first secret key. Delivery can be performed, and high security can be ensured at the time of key delivery from the first mobile station to the second mobile station.

In the secret key distribution system according to the fourth aspect of the present invention, the first secret key used for the cryptographic communication between the mobile station and the wired terminal that performs wireless communication with the base station is used as described above.
A system for delivering between a mobile station and a wired terminal,
A mobile station is registered and includes a master unit connected to a wired communication network, and a second unit used for encrypted communication between the mobile station and the master unit.
The mobile station and the base unit establish a cryptographic communication path between the mobile station and the base unit using the second secret key, and share the first secret key with the cryptographic communication path. Means for delivering between the mobile station and the master unit via the mobile station, the master unit includes relay means for delivering the first secret key received from one of the mobile station and the wired terminal to the other. , The first secret key is distributed between the mobile station and the wired terminal via the master unit.

Therefore, the first secret key can be safely delivered between the insecure mobile station and the base station included in the first secret key delivery section without using an advanced encryption method such as a public key encryption method. , And high security can be ensured at the time of key distribution between them.

In the secret key distribution system according to the fifth aspect of the present invention, as described above, the first secret key used for the encrypted communication between the mobile station performing the wireless communication with the base station and the wired terminal includes:
A system for delivering from a mobile station to a wired terminal, wherein the mobile station is registered, includes a master unit connected to a wired communication network, and a second secret used for encrypted communication between the mobile station and the master unit. The key is shared between the two, and the mobile station has encryption means for encrypting data including at least the first secret key using the second secret key, and encrypts the encrypted data. The master unit transmits to the master unit, the master unit has a decryption unit for decrypting the encrypted data received from the mobile station using the second secret key, and transmits the first secret key via the wired communication network. This is a configuration for transmitting to a wired terminal.

Therefore, the first secret key can be safely delivered between the insecure mobile station and the base station included in the first secret key delivery section without using an advanced encryption method such as a public key encryption method. , And high security can be ensured at the time of key distribution from the mobile station to the wired terminal.

In the secret key distribution system according to the sixth aspect of the present invention, as described above, in the configuration of the fifth aspect of the present invention, the identification information of the mobile station together with the first secret key is transmitted to the mobile station via the master unit. To the wired terminal, and the wired terminal has a determination unit for determining whether or not the other party is the mobile station that has requested the cryptographic communication at the time of the incoming call based on the identification information of the mobile station. Configuration.

Therefore, in addition to the effect of the fifth aspect of the present invention, the wired terminal on the encrypted communication response side determines whether the other party is a true encrypted communication requesting station at the time of incoming call (before the start of encrypted communication). By making the determination, the effect that higher security can be ensured is also achieved.

According to the secret key distribution system of the present invention, as described above, the first secret key used for the encrypted communication between the mobile station and the wired terminal that performs wireless communication with the base station is used as the first secret key.
A system for delivering from a wired terminal to a mobile station, wherein the mobile station is registered, includes a master unit connected to a wired communication network, and a second secret used for cryptographic communication between the mobile station and the master unit. The key is shared between the two, and the wired terminal transmits a first secret key to the master via a wired communication network, and the master uses at least the first secret by using the second secret key. The mobile station transmits the encrypted data to the mobile station, and the mobile station transmits the encrypted data received from the master unit to a second secret key. This is a configuration having a decoding means for decoding using.

Therefore, the first secret key can be safely delivered between the insecure mobile station and the base station included in the first secret key delivery section without using an advanced encryption method such as a public key encryption method. , And high security can be ensured at the time of key distribution from the wired terminal to the mobile station.

As described above, in the secret key distribution system according to the eighth aspect of the present invention, in the configuration of the seventh aspect, the number of the wired terminal together with the first secret key is transmitted from the wired terminal via the master unit. Sent to a mobile station, the mobile station has a determining means for determining whether or not the other party is a wired terminal that has requested cryptographic communication at the time of an incoming call, based on the identification information of the wired terminal. It is.

Therefore, in addition to the effect of the seventh aspect of the present invention, the mobile station on the cryptographic communication response side determines whether or not the other party is a true cryptographic communication requesting terminal at the time of incoming call (before starting cryptographic communication). By making the determination, the effect that higher security can be ensured is also achieved.

[0293] The secret key distribution system according to the ninth aspect of the present invention provides, as described above, the first key for performing wireless communication with a base station.
A system for delivering a first secret key used for cryptographic communication between a mobile station and a second mobile station from the first mobile station to the second mobile station, wherein the first mobile station is registered and wired communication is performed. A first base unit connected to the network and a second mobile station are registered;
A second base station connected to a wired communication network, wherein the second mobile station shares a second secret key used for cryptographic communication between the first mobile station and the first base station, and A third secret key used for encrypted communication between the first mobile station and the second base station, and the first mobile station encrypts data including at least the first secret key using the second secret key. And transmitting the encrypted data to a first master unit, wherein the first master unit encrypts the encrypted data received from the first mobile station with a second secret key. A first decryption means for decrypting using the key, transmitting the first secret key to the second parent device via the wired communication network, wherein the second parent device uses the third secret key to perform at least A second encryption unit for encrypting data including the first secret key, transmitting the encrypted data to a second mobile station, The second decrypted using the third secret key encrypted data received from the second mobile station
This is a configuration having decoding means.

Therefore, without using an advanced encryption method such as a public key encryption method, the first secret key can be securely transmitted between each insecure mobile station and the base station included in the distribution section of the first secret key. Delivery can be performed, and high security can be ensured at the time of key delivery from the first mobile station to the second mobile station.

[0295] In the secret key distribution system according to the tenth aspect of the present invention, as described above, in the configuration of the ninth aspect of the present invention, the first mobile station includes, together with the data encrypted by the first encrypting means, A request is made to deliver the communication number of the second base station in which the second mobile station is registered and the first secret key to the second mobile station via the second base station in which the second mobile station is registered. A first delivery request is transmitted to the first master unit, and the first master unit responds to the notification of the communication number of the second master unit from the first mobile station and a first decryption request in response to the first delivery request. A second delivery request for delivering the first secret key to the second mobile station is sent to the second mobile station via the wired communication network together with the first secret key decrypted by the encrypting means.
The second base station transmits the data encrypted by the second encryption means to the second mobile station in response to the second delivery request from the first base station.

Therefore, in addition to the effect of the ninth aspect of the present invention, even if the first master unit does not know the communication number of the second master unit before key distribution, the first mobile station can switch to the second mobile station. In addition, the first secret key can be surely delivered to the user.

[0297] In the secret key distribution system according to the eleventh aspect of the present invention, as described above, in the configuration of the tenth aspect of the present invention, the first mobile station is a second parent in which the second mobile station is registered. A number notification request for notifying the first mobile station of the communication number of the device to the second mobile station, and the second mobile station responds to the first mobile station in response to the number notification request. Notifying the communication number of the second base unit, the first mobile station receives the notification of the communication number of the second base unit from the second mobile station,
The communication number of the second master unit and the first delivery request
This is a configuration for transmitting to the master unit.

Therefore, in addition to the effects of the tenth aspect, even if not only the first base station but also the first mobile station do not know the communication number of the second base station before the key distribution, the first The first secret key can be reliably delivered from the mobile station to the second mobile station.

[0299] In the secret key distribution system according to the twelfth aspect of the present invention, as described above, in the configuration of the ninth aspect of the present invention, the first mobile station includes, together with the data encrypted by the first encryption means, A first delivery request for delivering the first secret key to the second mobile station is transmitted to the first base unit, and the communication number of the second base unit in which the second mobile station is registered is set to the second base station. 1
The second mobile station transmits a number notification request for notifying the base unit to the second mobile station, and the second mobile station transmits a second notification to the first base station in response to the number notification request from the first mobile station. Notifying the communication number of the master unit, the first master unit receives the first delivery request from the first mobile station and the notification of the communication number of the second master unit from the second mobile station. 1 The first decrypted by the decryption means
A second delivery request for delivering the first secret key to the second mobile station together with the secret key is transmitted to the second master via the wired communication network, and the second master is transmitted to the first master by the first master. In this configuration, the data encrypted by the second encrypting means is transmitted to the second mobile station in response to a second delivery request from.

Therefore, in addition to the effect of the ninth aspect, the first mobile station and the first mobile station on the cryptographic communication request side before the key distribution.
The first secret key can be reliably delivered from the first mobile station to the second mobile station even if none of the masters knows the communication number of the second master.

According to a thirteenth aspect of the present invention, in the secret key distribution system according to the ninth aspect of the present invention, the first mobile station includes, together with the data encrypted by the first encryption means, Transmitting a first delivery request for delivering the first secret key to the second mobile station to the first base unit,
The master unit responds to the first delivery request from the first mobile station,
The second mobile station transmits a number notification request to notify the first base station of the communication number of the second base station in which the second mobile station is registered, to the second mobile station. The first base unit notifies the first base unit of the communication number of the second base unit in response to the number notification request from the base unit, and the first base unit transmits the communication number of the second base unit from the second mobile station.
Upon receiving the notification of the communication number of the master unit, a second delivery request for delivering the first secret key to the second mobile station is sent together with the first secret key decrypted by the first decryption means. To the second base station, and the second base station transmits the data encrypted by the second encryption means to the second mobile station in response to the second delivery request from the first base station It is a configuration to do.

Therefore, in addition to the effect of the ninth aspect of the present invention, the first mobile station and the first mobile station on the cryptographic communication request side before the key distribution.
The first secret key can be reliably delivered from the first mobile station to the second mobile station even if none of the masters knows the communication number of the second master.

[0303] In the secret key distribution system according to the fourteenth aspect of the present invention, as described above, in the configuration of the ninth aspect of the present invention, the first mobile station includes, together with the data encrypted by the first encryption means, A first delivery request for delivering the first secret key to the second mobile station is transmitted to the first base unit, and the communication number of the second base unit in which the second mobile station is registered is set to the second base station. 1
A first number notification request for notifying the base unit is transmitted to the second mobile station, and the second mobile station responds to the first number notification request from the first mobile station to transmit the first number notification request to the second base station. A second delivery request for delivering the first secret key to the second mobile station is transmitted to the second base unit together with a second number notification request for notifying the first base unit of the communication number, and In response to the second number notification request and the second delivery request from the second mobile station, the second master unit transmits the first secret key together with the communication number of the second master unit to the second master unit via the second master unit. 2 Third requiring delivery to mobile station
A delivery request is transmitted to the first master unit, and the first master unit receives a first delivery request from the first mobile station and a second delivery request from the second master unit.
In response to the communication number of the master unit and the third delivery request, a fourth delivery request for delivering the first secret key to the second mobile station is sent together with the first secret key decrypted by the first decryption means. The second master transmits the data encrypted by the second encryption unit to the second master in response to the fourth delivery request from the first master via the wired communication network. This is a configuration for transmitting to a station.

Therefore, in addition to the effect of the ninth aspect of the present invention, the first mobile station and the first mobile station on the cryptographic communication request side before the key distribution.
The first secret key can be reliably delivered from the first mobile station to the second mobile station even if none of the masters knows the communication number of the second master.

As described above, in the secret key distribution system according to the fifteenth aspect of the present invention, in the configuration of the ninth aspect of the present invention, the first mobile station includes: Transmitting a first delivery request for delivering the first secret key to the second mobile station to the first base unit,
The master unit responds to the first delivery request from the first mobile station,
A first number notification request for notifying the first master unit of the communication number of the second master unit in which the second mobile station is registered is sent to the second master unit.
The second mobile station transmits to the mobile station, and in response to the first number notification request from the first master, requests the second master to notify the first master of the communication number of the second master. A second delivery request for delivering the first secret key to the second mobile station is transmitted to the second base station together with the number notification request, and the second base station transmits the second number from the second mobile station. In response to the notification request and the second delivery request, a third request for delivering the first secret key to the second mobile station via the second master device together with the communication number of the second master device.
A delivery request is transmitted to the first master unit, and the first master unit receives a first delivery request from the first mobile station and a second delivery request from the second master unit.
In response to the communication number of the master unit and the third delivery request, a fourth delivery request for delivering the first secret key to the second mobile station is sent together with the first secret key decrypted by the first decryption means. The second master transmits the data encrypted by the second encryption unit to the second master in response to the fourth delivery request from the first master via the wired communication network. This is a configuration for transmitting to a station.

Therefore, in addition to the effect of the ninth aspect, the first mobile station and the first mobile station on the cryptographic communication request side before the key distribution.
The first secret key can be reliably delivered from the first mobile station to the second mobile station even if none of the masters knows the communication number of the second master.

[0307] According to the secret key distribution system according to the sixteenth aspect of the present invention, in the configuration according to any one of the ninth to fifteenth aspects, the identification information of the first mobile station is provided together with the first secret key. Is transmitted from the first mobile station to the second mobile station via the first and second base stations, and the second mobile station performs encryption based on the identification information of the first mobile station when receiving a call. This is a configuration having a determination means for determining whether or not the mobile station has requested communication.

Therefore, in addition to the effects of the present invention as defined in any one of claims 9 to 15, the encryption communication responding side has
The mobile station determines whether or not the other party is a true cryptographic communication requesting station at the time of receiving a call (before the start of the cryptographic communication), thereby providing an effect that higher security can be ensured.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is a schematic configuration diagram of a secret key distribution system.

FIG. 2 is a block diagram showing a configuration of a main part of a mobile station of the secret key distribution system.

FIG. 3 is a block diagram showing a configuration of a main part of a master unit of the secret key distribution system.

FIG. 4 is a block diagram showing a configuration of a main part of a partner wired terminal of the secret key distribution system.

FIG. 5 is a communication sequence diagram showing an example of a communication procedure of the secret key distribution system.

FIG. 6 is a communication sequence diagram showing another example of a communication procedure of the secret key distribution system.

FIG. 7 is a communication sequence diagram showing still another example of the communication procedure of the secret key distribution system.

FIG. 8 shows another embodiment of the present invention, and is a schematic configuration diagram of a secret key distribution system.

FIG. 9 is a block diagram showing a configuration of a main part of a wired terminal of the secret key distribution system.

FIG. 10 is a block diagram showing a configuration of a main part of a master unit of the secret key distribution system.

FIG. 11 is a block diagram showing a configuration of a main part of a mobile station of the secret key distribution system.

FIG. 12 illustrates still another embodiment of the present invention, and is a schematic configuration diagram of a secret key distribution system.

FIG. 13 is a block diagram showing a configuration of a main part of a first mobile station of the secret key distribution system.

FIG. 14 is a block diagram showing a configuration of a main part of a first master unit of the secret key distribution system.

FIG. 15 is a block diagram showing a configuration of a main part of a second parent device of the secret key distribution system.

FIG. 16 is a block diagram showing a configuration of a main part of a second mobile station of the secret key distribution system.

FIG. 17 is a communication sequence diagram showing an example of a communication procedure of the secret key distribution system.

FIG. 18 is a communication sequence diagram showing another example of the communication procedure of the secret key distribution system.

FIG. 19 is a communication sequence diagram showing still another example of the communication procedure of the secret key distribution system.

FIG. 20 shows still another embodiment of the present invention, and is a schematic configuration diagram of a secret key distribution system.

FIG. 21 is a block diagram showing a configuration of a main part of a first mobile station of the secret key distribution system.

FIG. 22 is a block diagram showing a configuration of a main part of a first master unit of the secret key distribution system.

FIG. 23 is a block diagram showing a configuration of a main part of a second mobile station of the secret key distribution system.

FIG. 24 is a communication sequence diagram showing an example of a communication procedure of the secret key distribution system.

FIG. 25 shows still another embodiment of the present invention, and is a schematic configuration diagram of a secret key distribution system.

FIG. 26 is a block diagram showing a configuration of a main part of a first mobile station of the secret key distribution system.

FIG. 27 is a block diagram showing a configuration of a main part of a first master unit of the secret key distribution system.

FIG. 28 is a block diagram showing a configuration of a main part of a second mobile station of the secret key distribution system.

FIG. 29 is a communication sequence diagram showing an example of a communication procedure of the secret key distribution system.

FIG. 30 shows still another embodiment of the present invention, and is a schematic configuration diagram of a secret key distribution system.

FIG. 31 is a block diagram showing a configuration of a main part of a first master unit of the secret key distribution system.

FIG. 32 is a block diagram showing a configuration of a main part of a second parent device of the secret key distribution system.

FIG. 33 is a block diagram showing a configuration of a main part of a second mobile station of the secret key distribution system.

FIG. 34 is a communication sequence diagram showing an example of a communication procedure of the secret key distribution system.

FIG. 35 shows yet another embodiment of the present invention, and is a schematic configuration diagram of a secret key distribution system.

FIG. 36 is a block diagram showing a configuration of a main part of a first master unit of the secret key distribution system.

FIG. 37 is a block diagram showing a configuration of a main part of a second mobile station of the secret key distribution system.

FIG. 38 is a communication sequence diagram showing an example of a communication procedure of the secret key distribution system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ISDN (wired communication network) 2.2a 2b Public base station (base station) 514 Encryption part (encryption means) 8.16 Decryption part (decryption means) 11.18.35 Judgment part (judgment) Means) 23 First encryption unit (first encryption unit) 27 First decryption unit (first decryption unit) 30 Second encryption unit (second encryption unit) 33 Second decryption unit (second unit) Decryption means)

Claims (16)

[Claims] 1. A secret key delivery method for delivering a first secret key used for encrypted communication between a mobile station and a wired terminal performing wireless communication with a base station from the mobile station to the wired terminal, An encryption communication path between the mobile station and the base unit is established by a preset second secret key shared between the mobile station and the base unit with which the mobile station is registered, and the first secret key is Delivering the first secret key delivered from the mobile station from the base station to the wired terminal via the wired communication network, comprising: delivering the first secret key delivered from the mobile station to the wired terminal via the encrypted communication path; And delivering the first secret key via a private key. 2. A method for delivering, from a wired terminal to a mobile station, a first secret key used for encrypted communication between the mobile station and a wired terminal performing wireless communication with a base station, the method comprising: Distributing a key from a wired terminal to a parent device in which the mobile station is registered via a wired communication network; and a mobile station using a second preset secret key shared between the mobile station and the parent device. Establishing a cryptographic communication path between the base station and the base station, and distributing the first secret key delivered from the wired terminal to the mobile station from the base station via the cryptographic communication path. And distributing the first secret key by using the secret key distribution method. 3. A first secret key used for encrypted communication between a first mobile station and a second mobile station performing wireless communication with a base station,
A secret key distribution method for distributing a secret key from a first mobile station to a second mobile station, the method comprising: a preset secret key shared between the first mobile station and a first master unit in which the first mobile station is registered. The second secret key establishes an encrypted communication path between the first mobile station and the first master unit, and the first secret key is transmitted from the first mobile station to the first mobile station via the encrypted communication path.
Delivering the first secret key delivered from the first mobile station to the second base station in which the second mobile station is registered via a wired communication network; Establishing a cryptographic communication path between the second mobile station and the second base station by using a preset third secret key shared between the second mobile station and the second base station; Distributing the first secret key delivered from the second base station to the second mobile station via the cryptographic communication path, and distributing the first secret key via the first and second base stations. A secret key distribution method. 4. A secret key distribution system for distributing a first secret key used for encryption communication between a mobile station and a wired terminal performing wireless communication with a base station between the mobile station and the wired terminal. The mobile station is registered, includes a master unit connected to a wired communication network, and is used for encryption communication between the mobile station and the master unit.
The mobile station and the base unit establish a cryptographic communication path between the mobile station and the base unit using the second secret key, and share the first secret key with the cryptographic communication path. Means for delivering between the mobile station and the parent device via the mobile device, the master device comprising: relay means for delivering the first secret key received from one of the mobile station and the wired terminal to the other. A secret key distribution system for distributing a first secret key between a mobile station and a wired terminal via a parent device. 5. A secret key distribution system for distributing a first secret key used for encryption communication between a mobile station and a wired terminal performing wireless communication with a base station from the mobile station to the wired terminal, A mobile station is registered and includes a master unit connected to a wired communication network, and a second unit used for encrypted communication between the mobile station and the master unit.
The mobile station shares a secret key with each other, and the mobile station uses at least the first secret key by using the second secret key.
An encryption unit for encrypting data including a secret key, transmitting the encrypted data to a master unit, wherein the master unit encrypts the encrypted data received from the mobile station with a second secret key; And decoding means for decoding using
A secret key distribution system for transmitting a secret key to a wired terminal via a wired communication network. 6. An identification information of a mobile station together with a first secret key is transmitted from the mobile station to a wired terminal via a master unit. 6. The secret key distribution system according to claim 5, further comprising a judgment unit for judging whether the mobile station is a mobile station that has requested cryptographic communication. 7. A secret key distribution system for distributing a first secret key used for encryption communication between a mobile station performing wireless communication with a base station and a wired terminal from the wired terminal to the mobile station, A mobile station is registered and includes a master unit connected to a wired communication network, and a second unit used for encrypted communication between the mobile station and the master unit.
The secret key is shared between the two, the wired terminal transmits a first secret key to the master via a wired communication network, and the master uses at least a first secret key using the second secret key. Transmitting an encrypted data to the mobile station, wherein the mobile station transmits the encrypted data received from the master unit to a second secret key; A secret key distribution system comprising a decryption means for decrypting using a secret key. 8. The wired terminal number is transmitted from the wired terminal to the mobile station via the master unit together with the first secret key. 8. The secret key distribution system according to claim 7, further comprising a determination unit configured to determine whether the terminal is a wired terminal that has requested encryption communication. 9. A first secret key used for encrypted communication between a first mobile station and a second mobile station performing wireless communication with a base station,
A secret key distribution system for distributing a first mobile station from a first mobile station to a second mobile station, wherein the first mobile station is registered, and the first master unit connected to the wired communication network and the second mobile station are registered. And a second master unit connected to the wired communication network, wherein the second secret key used for the cryptographic communication between the first mobile station and the first master unit is shared between the two. The second mobile station and the second
A third secret key used for cryptographic communication with the master unit is shared between the two, and the first mobile station uses the second secret key to generate at least the first secret key.
A first encryption unit for encrypting data including a secret key, transmitting the encrypted data to a first base unit, wherein the first base unit receives the encrypted data from the first mobile station; First decryption means for decrypting the obtained data using the second secret key, transmitting the first secret key to the second parent device via a wired communication network, wherein the second parent device A second encryption unit that encrypts data including at least the first secret key using the three secret keys,
Transmitting the encrypted data to a second mobile station, wherein the second mobile station decrypts the encrypted data received from the second mobile station using a third secret key; Secret key distribution system comprising means. 10. The first mobile station transmits, together with the data encrypted by the first encryption means, the communication number of the second base station in which the second mobile station is registered, and the first secret key to the second mobile station. The mobile station transmits a first delivery request to the first base station for delivery to the second mobile station via the registered second base station, and the first base station transmits the first mobile station to the first mobile station. In response to the notification of the communication number of the second master unit and the first delivery request, the delivery of the first secret key to the second mobile station together with the first secret key decrypted by the first decryption means. The requested second delivery request is transmitted to the second master via the wired communication network, and the second master is encrypted by the second encryption means in response to the second delivery request from the first master. 10. The secret key distribution system according to claim 9, wherein the transmitted data is transmitted to a second mobile station. 11. The first mobile station transmits to the second mobile station a number notification request for notifying the first mobile station of the communication number of the second master unit in which the second mobile station is registered. The second mobile station notifies the first mobile station of the communication number of the second base unit in response to the number notification request, and the first mobile station transmits a second mobile station communication number from the second mobile station. 11. The secret key distribution system according to claim 10, wherein upon receiving the communication number of the second master unit, the communication number of the second master unit and the first delivery request are transmitted to the first master unit. . 12. The first mobile station sends, to the first master unit, a first delivery request for delivering a first secret key to a second mobile station together with data encrypted by the first encryption means. The second mobile station transmits a number notification request to the second mobile station for transmitting the communication number of the second parent device in which the second mobile station is registered to the first parent device. Notifies the first base unit of the communication number of the second base unit in response to the number notification request from the first mobile station, and the first base unit transmits the second base unit's communication number from the first mobile station. Upon receiving the first delivery request and the notification of the communication number of the second master unit from the second mobile station, the first secret key is delivered to the second mobile station together with the first secret key decrypted by the first decryption means. Transmitting a second delivery request to the second base unit via a wired communication network, wherein the second base unit sends a second delivery request from the first base unit. In response, the secret key distribution system according to claim 9, wherein the transmitting the data encrypted in the second encryption unit to the second mobile station. 13. The first mobile station sends, to the first master unit, a first delivery request for delivering a first secret key to a second mobile station together with the data encrypted by the first encryption means. The first base unit transmits the communication number of the second base unit in which the second mobile station is registered to the first base unit in response to the first delivery request from the first mobile station. The second mobile station transmits a number notification request to the first base unit in response to the number notification request from the first base unit. The first master unit receives the notification of the communication number of the second master unit from the second mobile station, and sends the first secret key together with the first secret key decrypted by the first decryption means. To the second base unit via a wired communication network, requesting that the second base station be delivered to the second mobile station. The secret key delivery system according to claim 9, wherein the data encrypted by the second encryption means is transmitted to the second mobile station in response to the second delivery request. 14. The first mobile station sends a first delivery request for delivering the first secret key to the second mobile station to the first master unit together with the data encrypted by the first encryption means. Transmitting a first number notification request to the second mobile station for transmitting the communication number of the second base station with which the second mobile station is registered to the first base station; The mobile station, in response to the first number notification request from the first mobile station, sends a first secret key together with a second number notification request for notifying the first base unit of the communication number of the second base unit. To the second base station, and the second base station responds to the second number notification request and the second delivery request from the second mobile station. And a third delivery requesting delivery of the first secret key together with the communication number of the second base station to the second mobile station via the second base station. The determined and transmitted to the first master unit, the first master unit, first delivery request from the first mobile station,
Upon receiving the communication number of the second base unit and the third delivery request from the second base unit, the first secret key is delivered to the second mobile station together with the first secret key decrypted by the first decryption means. A second delivery request is sent to the second master device via the wired communication network, and the second master device responds to the fourth delivery request from the first master device by the second encryption means. The secret key distribution system according to claim 9, wherein the encrypted data is transmitted to the second mobile station. 15. The first mobile station sends a first delivery request for delivering a first secret key to a second mobile station together with the data encrypted by the first encryption means to the first base station. The first base unit transmits the communication number of the second base unit in which the second mobile station is registered to the first base unit in response to the first delivery request from the first mobile station. The first mobile station transmits a first number notification request to the second mobile station, and the second mobile station changes the communication number of the second base station to the second mobile station in response to the first number notification request from the first base station. A second delivery request for delivering the first secret key to the second mobile station is sent together with a second number notification request for notifying the first base station to the second mobile station.
The second base unit transmits the first secret key together with the communication number of the second base unit in response to the second number notification request and the second delivery request from the second mobile station. A third delivery request for delivery to the second mobile station via the two masters is transmitted to the first master, wherein the first master requests a first delivery request from the first mobile station;
Upon receiving the communication number of the second base unit and the third delivery request from the second base unit, the first secret key is delivered to the second mobile station together with the first secret key decrypted by the first decryption means. A second delivery request is sent to the second master device via the wired communication network, and the second master device responds to the fourth delivery request from the first master device by the second encryption means. The secret key distribution system according to claim 9, wherein the encrypted data is transmitted to the second mobile station. 16. The identification information of the first mobile station together with the first secret key is transmitted from the first mobile station to the second mobile station via the first and second base units, and the second mobile station is 11. A system according to claim 9, further comprising a judgment unit for judging whether or not the other party is a mobile station that has requested the cryptographic communication at the time of receiving the call, based on the identification information of the first mobile station. 11, 12, 13, 14, or 15
Private key distribution system as described.