JP3630874B2 - Communication apparatus and system and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication apparatus, system, and method in a multimedia network that transmits information such as moving image data, still image data, audio data, and computer data.
[0002]
[Prior art]
B-ISDN (Broadband Aspects of Integrated Services Digital Network), which is being studied as a next-generation backbone communication infrastructure, has a larger transmission capacity than the currently implemented ISDN (network). It is a flexible network that can provide communication services with the required transmission capacity (as long as resources allow). This kind of service is possible due to the basic technology of B-ISDN, which is called ATM (Asynchronous Transfer Mode). In ATM, as in the packet-switched transmission mode, a fixed-length cell with a header storing a label with a destination written is sent to cope with an arbitrary speed, and the switch is switched by reading the label. . By configuring the packet in units of fixed-length cells, high-speed synchronous communication can be performed at the physical layer level, and an arbitrary transfer rate can be secured depending on the packet transmission density.
[0003]
On the other hand, network security technologies such as encryption and authentication are required for users to use such communication infrastructure with peace of mind. This encryption and authentication is a common key encryption method (also called a secret key encryption method, a symmetric encryption method, a conventional encryption method) in which the sender and the receiver share the same encryption key secretly, and the encryption key and the decryption key are different. It is known that it can be realized by a public key encryption method in which the encryption key is made public and the decryption key is kept secret (for details of each encryption method, see Ikeno and Koyama, “Modern Cryptography”, IEICE, 1986). Various key distribution methods have been proposed for such a method for securely distributing keys (see, for example, “Encryption and Information Security” by Shoji and Kasahara, 1990). By using the technique as described above, it is possible to realize safe communication even for B-ISDN.
[0004]
[Problems to be solved by the invention]
In the encryption / authentication communication as described above, in order to increase the security, the keys are often used in a hierarchy as shown in FIG. This is because if the key is analyzed, all subsequent data will be decrypted. Therefore, by encrypting the key with a higher-level key, security can be improved, or a key with a different purpose (signature key and This is performed in order to simultaneously realize the encryption and authentication functions by using a plurality of encryption keys and the like. In this case, if encryption is replaced according to decryption, signature, verification, and use, various functions are supported.
[0005]
In the figure, the first key for key encryption is called a master key, the key for directly encrypting data is called a work key, and the other keys are called key encryption keys. Some key encryption keys including the master key may be keys that have been delivered to the user in advance, or public keys that anyone can access. In addition, some key encryption keys including work keys are keys set by the sender, receiver, or the center that manages the key on the spot, saves the key search, Or a key sent with the data to identify
[0006]
Such keys are often sent to the recipient along with the encrypted or signed data and / or separately. Therefore, encryption / authentication communication includes communication related to a key in addition to communication related to data. It is clear that the safety related to the communication is more important for the communication related to the upper hierarchy in FIG. This is because all communications related to lower layers are unreliable unless communications related to higher layers are reliable. However, in conventional communication, a method has been proposed in which key information and data information related to the upper and lower layers are not distinguished from each other or are distinguished from each other in terms of the importance of information even if they are distinguished by the position of information. It wasn't.
[0007]
[Means for Solving the Problems]
The present invention has been made in view of the above situation, and a plurality of different communication qualities using a single transmission path for keys and data according to the importance such as the height of the hierarchy to which the keys and data belong. It is an object of the present invention to provide a communication apparatus, system, and method that can be transmitted over the Internet .
[0008]
In order to solve this problem, for example, the communication apparatus of the present invention has the following configuration.
[0009]
A key that belongs to an upper layer is hierarchically configured to convert a key or data that belongs to a lower layer, and a plurality of keys or data that belong to different layers are transmitted via one transmission path, An encryption / authentication system communication device capable of providing communication quality communication,
Storage means for storing quality corresponding to each hierarchy to which the key or data belongs;
Setting means for setting the quality of the transmission path based on the hierarchy information indicating the hierarchy and the storage content of the storage means,
The storage unit and the setting unit are characterized in that the higher the hierarchy , the higher the quality of the transmission path when transmitting the key or data.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.
[0011]
First, in this embodiment, B-ISDN allows different traffic characteristics for each medium in order to handle multimedia. Therefore, different QOS (Quality Of Service: quality of service) is required for each medium. As QOS in ATM, delay, sensitivity of delay variation, cell loss rate, and the like are defined as a set of parameters (the other QOS parameters are for further study).
[0012]
Here, the delay is the time from when the data is transmitted until it is received, and the delay variation is the variation in the cell transfer time due to congestion or the like. In the case of video transmission, the delay variation will cause the screen to flicker if the receiving side does not have sufficient buffer memory to cause bit fluctuation. In addition, when the delay becomes large, a device such as echo cancellation is required for a device that requires real-time performance such as voice data for conversation. On the other hand, for text data with little real-time property, there is no problem with delay and delay variation. The cell loss rate defines the ratio between the total number of cells sent by the caller and the total number of cells that do not reach the callee. In video transmissions where data flows down, frame loss or noise occurs. The communication quality is greatly affected. In addition, it can be understood that a compression method based on predictive coding such as MPEG, which has recently been studied, can cause even greater image quality degradation. In this way, each parameter of QOS has different requirements depending on the application.
[0013]
Request / setting of QOS between the user and the network is performed as follows. The user requests a class of QOS from among the QOS classes provided by the network (a combination of several QOS parameters). This is usually performed at the communication setting stage (when possible, re-setting even during communication) together with a traffic contract or the like. At this time, the network determines whether the requested traffic does not exceed the actual transmission capacity, and at the same time, determines whether the requested QOS class can be secured, etc., and notifies the terminal if communication is possible and enters the communication mode. . In the communication mode, as long as the user complies with the traffic contract, the network maintains the required QOS and guarantees the required quality.
[0014]
In addition, various protocols (communication rules) are defined in communication, and in the B-ISDN protocol, protocol hierarchies as shown in FIG. 7 are provided so that addition or change of various functions does not affect the whole. Has been done. The promise of delivery is decided between each hierarchy, and each hierarchy is called a layer. In FIG. 7, the physical layer is literally a regulation related to physical media (including cable and connector specifications, including transmission frame configuration, cell insertion and extraction functions), and the ATM layer is a cell multiplexing common to all services. And exchange. AAL (ALT adaptation layer) handles functions depending on each service, and a plurality of protocols are defined corresponding to each service. By this AAL, the addition and change of higher layer functions depending on each service are absorbed, and the basic functions of the B-ISDN are not affected. Therefore, the conversion of QOS required by each service into the above-described ATM QOS and the inverse conversion are performed in an upper layer including AAL.
[0015]
Thus, in B-ISDN, the quality of communication can be specified using QOS.
[0016]
Therefore, in this embodiment, the importance (quality) corresponding to the hierarchy of FIG. 6 is set in this QOS, that is, the communication related to the upper hierarchy in the cell loss rate or the like has the quality of QOS higher than the communication related to the lower hierarchy. By having means for setting, communication according to the importance of information of encryption / authentication communication is realized.
[0017]
FIG. 1 shows a flowchart for an embodiment of the present invention. In the figure, as an example of means for realizing establishment of a connection having a QOS corresponding to a hierarchy, a QOS setting means for performing the QOS request / setting procedure as shown in FIG. 2 and a QOS corresponding to the hierarchy information received as a table are shown. As QOS storage means. Further, the overall control of the flowchart of FIG. 1 and the output of hierarchical information as a part thereof are performed by a control means such as a CPU. However, the hierarchical information K in the figure corresponds to the total number of hierarchical levels in FIG. Therefore, when a communication request occurs, the means of FIG. 1 first requests and sets the highest quality QOS with the hierarchical information as K. Using the connection, encryption / authentication communication of the key encryption key with the highest master key is performed. 1 closes the connection after the encryption / authentication communication is completed. Thereafter, the hierarchy information K is decreased by one, the connection corresponding to the hierarchy is requested and set again, the above operation is repeated, and the process ends when K = 0. However, if there is a key that does not require communication similar to the master key, the connection opening / closing process and encryption / authentication communication are omitted.
[0018]
If there is no key that does not require communication other than the master key, the process for determining the necessity of key communication is omitted. In addition, when the QOS is the same for several layers, it is not necessary to perform processing related to the opening and closing of connections for each layer. These control changes can be easily made by changing the programming of the control means. Furthermore, the present invention can be realized by programming a QOS corresponding to a hierarchy in advance without a QOS storage means. Further, even if the QOS is not fixed to the hierarchy, in the case of an upper hierarchy, processing such as requesting the highest QOS that can be requested at that time may be performed. Further, the QOS can be arbitrarily set by setting the QOS storage means, programming the QOS setting means, or the like, even if the upper layer is not necessarily high quality with respect to the lower layer. However, since the series of communications in FIG. 1 (spanning a plurality of connections) is related, an identifier or the like can be used for the communication to distinguish other communications.
[0019]
The above is effective for connection-type communication in which QOS is determined at the communication setting stage.
[0020]
<Second Embodiment>
In addition to various QOS, B-ISDN also offers various connection setting modes such as connection type that sets communication prior to information transfer and connectionless type that communicates information to the other party when transmission information occurs. doing. The above-described embodiment (first embodiment) is for connection-type communication. In the second embodiment, a connectionless type in which QOS can be changed during communication is shown.
[0021]
FIG. 8 shows an example of the configuration of a connectionless protocol. In the figure, CLNAP (Connectionless Network Access Protocol) is a part of the upper layer shown in FIG. 7 and is a layer that realizes a connectionless protocol. A PDU (Protocol Data Unit) format in the layer is shown in FIG. The PDU indicates a data unit that defines a protocol, and the SUD (Service Data Unit) is a data unit from a user who uses the protocol. In this case, the QOS is specified as 4-bit data in the header of the PDU, and this PDU is generated in the CLNAP layer. This PDU is cellized or synthesized at the AAL and ATM layers and transmitted via the physical layer. Therefore, the QOS can be set for each PDU in the connectionless type.
[0022]
Therefore, in the connectionless communication protocol, different PDUs are generated for each layer (for each different QOS), and the QOS is set according to the layer of the encryption information included in the PDU, whereby the importance of the information (layer) Communication according to the is realized. This can be realized by control in which the connection in FIG. 1 is replaced with PDU.
[0023]
FIG. 3 shows a conceptual diagram of the configuration in the second embodiment. The encryption means shown in the figure receives the input data and sends the encrypted information to the QOS setting means and the hierarchy information to the QOS storage means. However, it is assumed that the key for each user, such as a master key, is managed by a known key management means. If not (such as when the key is input from an external card), the key is encrypted via communication or the like. Is input to the conversion means. In addition, a temporary key such as a work key is generated using a known random number generation unit, a calculation unit, or the like. Also, encryption with these keys is realized by known cryptographic processing means, and the output cryptographic information is sent to the QOS setting means. Furthermore, since the use order of these keys is predetermined and the use order corresponds to the key hierarchy, the control means is based on the predetermined key use order (hierarchy), and the key management means (or A master key or the like from the outside) or a work key or the like from the random number generation means and the calculation means is given to the encryption processing means, and encryption is performed in accordance with the input of data corresponding thereto (the work key or the like may be data). The processing order is sent to the QOS storage means as hierarchical information.
[0024]
Next, the QOS storage means is constituted by storage means for storing the QOS corresponding to the hierarchy information as a table, and gives the QOS corresponding to the inputted hierarchy information to the QOS setting means. The QOS setting means sets and outputs the QOS to output data (predetermined information including the encryption information) at a predetermined position and / or format.
[0025]
Next, this embodiment for the receiving side will be described with reference to FIG.
[0026]
Consider a case where the receiving side receives communication by the means shown in the first embodiment. In FIG. 4, the QOS analyzing means decomposes the input data, decomposes the encryption information and the hierarchy information from a predetermined information position and format such as an identification signal, and sends them to the decryption means. In the decryption means, the control means retrieves the key from the key management means if the hierarchy information is information of the hierarchy managed by the key management means, inputs the key to the decryption processing means, and decrypts the encryption information. Further, if the decryption result is information of a hierarchy used as a key, the decryption result is temporarily stored in the key storage unit. In addition, when the hierarchy information is not managed by the key management means, the control means searches for information that is a key of the hierarchy from the held decryption results, and uses the decryption processing means as a key To decrypt and output the encryption information. However, the key may be generated by the calculation means based on the decryption result. Therefore, the QOS analysis means can be realized by a combination of processing means such as CPU and DSP, and storage means such as RAM, and the decryption processing means is a known decryption processing means and key management means corresponding to the encryption processing means of the first embodiment. It is obvious that the same means and control means as in the first embodiment can be realized by processing means such as a CPU and DSP, and the arithmetic means can also be easily realized by CPU and DSP.
[0027]
The above describes encryption and decryption, but if authentication is included, if encryption is signed and decryption is replaced with verification, the same method is used for authentication communication according to the importance of the key. It is clear that communication is possible. In the case of an apparatus that performs both transmission and reception, the components shown in FIGS. 3 and 4 are the same, and therefore it is easy to use means (program) obtained by combining the means shown in FIGS.
[0028]
<Third Embodiment>
In the first and second embodiments, means for realizing communication according to the importance of information in connection type and connectionless type communication are shown. In the present embodiment, a communication system that realizes communication according to the importance of information including the first and second embodiments will be described with reference to FIG.
[0029]
Here, as an example, the means in the first embodiment is incorporated in the sender terminal and / or the receiver terminal of FIG. 5, and the number of layers K = 2 in the hierarchy of FIG. 6, that is, the master key and the work key Only consider the case. In connection-type communication, a case where encryption / authentication processing relating to a key and data is performed by the following ID-based key sharing method is considered.
[0030]
[ID-based key sharing method]
There is a center that manages the key distribution means, and the center receives identification (ID) such as the name and telephone number of each entity, and uses a secret algorithm unique to the center to obtain a secret key corresponding to the ID. In this method, each entity is generated and sent to each entity, and each entity calculates and obtains an encryption key to be shared from the secret key and the public ID of the communication partner. This method is called an ID-based key sharing method, and can confirm a communication partner and share a key at the same time.
[0031]
This method is roughly classified into a method that does not require preliminary communication prior to encryption communication and a method that does not require preliminary communication. A method that requires preliminary communication cannot be used like an electronic mail in which only a message is encrypted and sent, but a method that does not require preliminary communication can be used like an email and has a wide range of use. However, a method that does not require preliminary communication has a problem that the secret of the center is exposed when many entities collide. The Okamoto (Sakae) key distribution method is well known as a method that requires backup communication, and the Matsumoto / Imai key distribution method is well known as a method that does not require backup communication (see Sakurai for details). , Kasahara, “Cryptography and Information Security”, Shoshodo, 1990, Chapter 4). The following is a key distribution method of Okamoto (Sakae) as a representative method that requires preliminary communication.
[0032]
Okamoto (Sakae) key distribution method:
1) The center publishes an RSA cipher that is one of public key cryptosystems as a one-way function. That is, two prime numbers p and q and a decryption key d are kept secret, n = (p · q), and an encryption key e is disclosed (the encryption key e and the decryption key d are e · d = 1 mod (p -1) and (q-1)). At the same time, the primitive element g of the finite fields GF (p) and GF (q) is also disclosed.
[0033]
2) Each user j registers his / her identifier IDj at the center at the time of joining the network, asks the center to calculate and transmit Sj = IDjd mod n, and manages it secretly.
[0034]
3) When performing key sharing, user A and user B perform communication / calculation as shown in i to iv below.
i. User A arbitrarily selects a random number kA and sends CA = SA · gkA mod n to user B.
ii. User B arbitrarily selects a random number kB and sends CB = SB · gkB mod n to user A.
iii. User B calculates y = (CAe / IDA) kB mod n (= ge · kA · kB mod n).
iv. User A calculates y = (CBe / IDB) kA mod n (= ge · kA · kB mod n).
[0035]
4) Both users A and B perform encrypted communication using y as a shared key.
[0036]
Here, the master key corresponds to Sj in 2), and the work key corresponds to y in 3). Therefore, each user has Sj of 2) in advance, and the processing and communication of 3) is encryption / authentication communication relating to the key, and 4) corresponds to encryption communication relating to the data. User A corresponds to the sender in FIG. 5 and user B corresponds to the receiver. Hereinafter, it is assumed that each terminal in FIG. 5 has known ID-based key sharing means in addition to the means shown in the first embodiment (usually, the above-mentioned Sj is obtained by the ID-based key sharing means. Managed).
[0037]
First, when the user A performs encryption / authentication communication with the user B, first, the network and the QOS are negotiated using the first embodiment with K = 2, and a connection having a high-quality QOS is established between the user B and the user B. Open. After the connection is established, the user A uses the known ID-based key sharing means with the user B to perform the processing / communication of 3), share the work key y with each other, and once terminate the connection. Thereafter, the network and the QOS are negotiated again with K = 1, and a connection with QOS of the following quality is established with the user B when K = 2. Using this connection, encryption communication with the user B using the work key y is realized.
[0038]
Next, in connectionless communication, the master key is shared in advance between the sender and the receiver and stored in each key management means, and the work key is a random number generated by the sender's random number generation means as it is. Consider the use case. In this case, the terminal of FIG. 5 includes the second embodiment.
[0039]
When the sender encrypts the data with the work key and sends it to the receiver, the sender first searches the key management means for the master key shared with the receiver, thereby obtaining the work key that is the output of the random number generation means. The encrypted PDU is formed together with the hierarchy information, and a high-quality QOS corresponding to the hierarchy is added from the QOS storage means to form an ATM cell and sent to the receiver. Further, the sender encrypts the data using the random number as a work key, configures the PDU together with the hierarchy information, attaches QOS of the quality below the QOS corresponding to the hierarchy from the QOS storage means, and similarly converts it into an ATM cell. To the recipient.
[0040]
The receiver specifies the encryption information, hierarchy information, sender, encryption number, presence / absence of encryption, etc. from the PDU obtained by combining the cells. However, the encryption number is information used to link the work key and the data encrypted with the key. Therefore, the receiver determines whether the information is encrypted with the master key from the presence / absence of encryption and the hierarchy information, and searches for the shared master key from the sender information. Further, the encryption information is decrypted using it as a key, and it is used as a work key and held in the key storage means together with the encryption number. When the PDU belongs to a lower layer, the work key having the same encryption number is retrieved from the key storage means, and the encryption information is decrypted using the work key as a key, and the data sent from the sender is obtained.
[0041]
As described above, it can be seen that the communication system of FIG. 5 can be applied to communication related to various keys and data.
[0042]
The above is an example for the sake of simplicity. However, when the first and second embodiments are externally attached, when FIG. 6 is multi-layered, keys other than Okamoto (Sakae) ID-based key sharing method are used. In the case of the sharing method, it is obvious that a similar communication system can be realized for each of cases where connection type communication and connection type communication coexist. The present embodiment is also effective when the encryption / authentication communication having the hierarchical structure as shown in FIG. 4 is realized at the sender and the receiver and the center by using one terminal of FIG. 5 as the center station for the key. It is clear that there is.
[0043]
<Other embodiments>
In the above embodiment, QOS is used to realize communication according to the importance of information. However, the means for realizing communication quality is not limited to QOS, and the present invention includes other realizing means. It is obvious that the embodiment can be easily realized by replacing the part relating to the QOS in FIGS.
[0044]
Note that the present invention may be applied to an apparatus composed of one device, even if the apparatus for realizing the above processing and the communication terminal are separated.
[0045]
Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and store the computer (or CPU or MPU) of the system or apparatus. Needless to say, this can also be achieved by reading and executing the program code stored in the medium.
[0046]
In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
[0047]
As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
[0048]
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.
[0049]
Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0050]
【The invention's effect】
As described above, according to the present invention, keys and data can be transmitted with a plurality of different communication qualities using one transmission path according to the importance such as the height of the hierarchy to which the keys and data belong. It becomes like this .
[0051]
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating a processing procedure according to an embodiment.
FIG. 2 is a conceptual diagram of a processing configuration in the embodiment.
FIG. 3 is a diagram showing a conceptual configuration diagram of a transmission side in the second embodiment.
FIG. 4 is a diagram illustrating a conceptual configuration of a receiving side in the second embodiment.
FIG. 5 is a diagram illustrating a configuration of a communication system according to a third embodiment.
FIG. 6 is a conceptual diagram of hierarchical encryption.
FIG. 7 is a diagram illustrating a hierarchy of protocols in the embodiment.
FIG. 8 is a diagram illustrating an example of a configuration of a connectionless protocol in the second embodiment.
FIG. 9 is a diagram illustrating a PDU format in the second embodiment.

Claims (5)

A key belonging to the upper layer is hierarchically configured to convert a key or data belonging to the lower layer, and a plurality of keys or data belonging to different layers are transmitted via one transmission path, An encryption / authentication system communication device capable of providing communication quality communication,
Storage means for storing quality corresponding to each layer to which the key or data belongs;
Setting means for setting the quality of the transmission path based on the hierarchy information indicating the hierarchy and the storage content of the storage means;
The communication device, wherein the storage unit and the setting unit have higher quality of the transmission path when transmitting the key or data as the hierarchy is higher. 2. The communication apparatus according to claim 1, further comprising setting means for arbitrarily setting transmission quality of the transmission path according to a hierarchy to which each key or data belongs. The communication apparatus according to claim 1, wherein the quality of the transmission path is a parameter defined as QOS in ATM communication. A communication system comprising the communication device according to claim 1. A key belonging to the upper layer is hierarchically configured to convert a key or data belonging to the lower layer, and a plurality of keys or data belonging to different layers are transmitted via one transmission path, An encryption / authentication system communication method capable of providing communication quality communication ,
Selecting the quality of the transmission path stored in accordance with the hierarchy information indicating the hierarchy by storing the quality corresponding to each hierarchy to which the key or data belongs, and setting the quality of the transmission path,
In this step, the higher the hierarchy to which the key or data belongs, the higher the quality of the transmission path when transmitting the key or data.

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