JPH0691527B2 - Communication network system - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a communication network system useful for commercial transactions, document transmission, and the like.

[Technical background of the invention and its problems]

In recent years, along with the enhancement of communication networks, various systems are being developed that maximize the advantages of the above communication networks such as home banking, home shopping, and farm banking. The biggest challenge in realizing such a system is how secure business transactions and document communications, etc., which are conducted in situations where the other party cannot see each other, and the ability to prove the transaction documents are secured. There is a point to do.

That is, in transactions and document communications carried out using this type of communication network, false declarations and forgery of transaction documents can be considered as typical examples of fraud.

This false declaration may be made, for example, even though the sender has sent certain information but has declared to the recipient that he does not remember to send such information, or vice versa. No, it means to declare that the information has been sent. Further, forgery of a transaction document can be performed by, for example, falsifying (rewriting) the content of the communication document received and recorded by the recipient in the transaction.
Or means forging. Such fraud leads to fraud in transactions and embezzlement of money.

Therefore, in order to prevent such fraud as much as possible, DES (Data Encryp
The encryption / decryption circuit equipped with a conventional encryption program such as a data encryption standard) is provided to encrypt communication information for communication.

That is, in the transmission terminal A, the encryption circuit 2 is transmitted via the input device 1.
The telegram which is the communication information input to is encrypted according to the keyword registered in the key memory 3, and is transmitted via the communication interface 5 connected to the communication line 4. Then, in the receiving terminal B, the encrypted electronic text received from the communication line 4 through the communication interface 6 is input to the decryption circuit 7, which is decrypted in accordance with the keyword registered in the key memory 8 to output the communication information. It outputs from 9. In this case, the above-mentioned keyword is unique between the two communication terminals A and B, and the contents of the communication are not leaked to anyone other than the communicating parties.

Therefore, if it can be assumed that the keyword registered in the keyword memory 8 is not leaked to the outside on the side of the receiving terminal B, and that the receiver does not perform fraud such as forgery of communication information, then the encryption of the above-mentioned electronic message is performed. Only the transmitting terminal A that knows the keyword can perform the conversion. Therefore, for example, if the encrypted telegram is stored in the receiving terminal B as it is, only the transmitting terminal A can create the encrypted telegram, so that the so-called digital signature of the communication information is possible here. Become. Then, it becomes possible to give evidence power to this encrypted telegram.

However, generally, a recipient who knows the content of a keyword can create an encryption program by using another computer, etc., and use the keyword without permission to create an encrypted message. Is. Therefore, it is a serious problem to assume that the receiving terminal B does not perform fraud.

For these reasons, the conventional communication network system has a problem in reliably preventing fraud on the sending side and the receiving side, and in the end it was not possible to ensure the safety of commercial transactions.

[Object of the Invention]

The present invention has been made in view of such circumstances, and an object of the present invention is to enable a reliable digital signature for communication information to sufficiently secure the security of commercial transactions and document communication, for example. It is to provide a communication network system capable of performing.

[Outline of Invention]

According to the present invention, one or a plurality of transmitting terminals and one receiving terminal are connected via a communication line, and each of the transmitting terminals encrypts communication information using an encryption device, and then transmits this to the communication line. In the communication network system for transferring to the receiving terminal by utilizing, each of the transmitting terminals stores a secret key determined for each of the encryption devices in an unreadable manner, and at least this storing section. Using the secret key stored in the above, an encryption device configured by sealingly integrating an encryption unit for encrypting communication information by a predetermined algorithm, and communication information encrypted by this encryption device A transmitting device for transmitting, the receiving terminal,
A receiving device for receiving communication information from the transmitting terminal, a storage unit storing all secret keys defined for each encryption device in an unreadable manner to the outside, and one of these secret keys.
For decrypting the encrypted communication information received by the receiving device with an algorithm different from the predetermined algorithm, using a key selecting unit for selecting one and at least the secret key selected by the key selecting unit. A decryption device having a decryption unit sealed and integrated, and the encryption unit is provided only in the encryption device provided in each of the transmission terminals.

Further, it is preferable that the encryption device and the decryption device each be formed of a semiconductor device that is provided inside a portable card in a sealed manner.

Also, preferably, the encryption device and the decryption device are each a data encryption standard (DES; Data).
The Encryption Standard) method may be used as the encryption / decryption algorithm.

Further, preferably, the key selection unit includes a code storage unit that stores a code for identifying the encryption device that stores the code for identifying the encryption device that has transmitted the encrypted and transmitted signal. Alternatively, the secret key defined in the encryption device may be selectively extracted according to this code.

On the other hand, according to the present invention, one transmitting terminal and one or a plurality of receiving terminals are connected via a communication line, and the transmitting terminal encrypts communication information and then uses the communication information to obtain a desired one. In the communication network system in which each of the receiving terminals transfers the received encrypted communication information to the receiving terminal by using the decoding device, the transmitting terminal is determined for each of the decoding devices. A storage unit that stores all of the secret keys in an unreadable manner externally, a key selecting unit that selects one of these secret keys, and at least a secret key that is selected by this key selecting unit, and uses a predetermined algorithm to communicate. Each of the receiving terminals includes an encryption device configured by sealingly integrating an encryption unit for encrypting information, and a transmission device for transmitting communication information encrypted by the encryption device. Is before A receiving device for receiving communication information from the transmitting terminal, a storage unit storing a secret key determined for each decryption device in an unreadable manner to the outside, and at least the secret key stored in the storage unit. A decryption device configured by sealingly integrating a decryption unit for decrypting encrypted communication information received by the receiving device with an algorithm different from the predetermined algorithm. The unit is provided only in the encryption device provided in the transmission terminal.

Further, it is preferable that the encryption device and the decryption device each be formed of a semiconductor device that is provided inside a portable card in a sealed manner.

Also, preferably, the encryption device and the decryption device are each a data encryption standard (DES; Data).
The Encryption Standard) method may be used as the encryption / decryption algorithm.

Further, preferably, the key selection unit includes a code storage unit that stores a code for identifying a destination decryption device that transmits the encrypted signal, and performs the decryption according to the code stored in the code storage unit. It may be configured to selectively extract the secret key defined in the device.

〔The invention's effect〕

Thus, according to the present invention, the encryption device and the decryption device are sealed and integrated inside the device in a state where the encryption and decryption processes are undecipherable, and the private key unique to the device is used. Moreover, since the encryption and the decryption are performed by different algorithms, it is possible to surely prevent the transmission terminal side and the reception terminal side from being illegal with respect to the encrypted telegram.

In other words, only the sending side terminal equipped with the encryption device can create the encrypted telegram for the communication information, or only the receiving side terminal equipped with the decryption device can decrypt the encrypted text. . Therefore, for example, by recording and storing the received encrypted telegram, a highly reliable digital signature for the encrypted telegram is possible.
Therefore, it becomes possible to enhance the reliability and safety of commercial transactions and document transmission using the communication network, and it is possible to exert a great practical effect such as enhancing the evidence ability of the recorded communication information.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.

1 to 5 show a first embodiment, which is a communication network system applicable to, for example, home banking, home shopping, farm banking and the like. As shown in FIG. 5, the system according to this embodiment includes a plurality of customer terminals 11a, 11b, to 11n installed on the customer side such as homes or businesses that are message senders, and banks that are message recipients. And a center-side terminal 12 installed on the only center side such as a department store or the like, and are connected via communication lines 13a, 13b, to 13n separately. And the customer terminal 11a, 11
So-called portable IC cards 14a, 14b, to 14n are mounted on b, to 11n, and a portable IC card 15 is mounted on the center-side terminal 12.
Is to be installed.

As shown in FIG. 1, the customer terminal 11 (11a, 11b, to 11n) is
The card reader / writer 21 to which the C cards 14 (14a, 14b, to 14n) are attached, and the electronic message M, which is communication information, is input to the IC card 14 via the card reader / writer 21. For example, it comprises an input device 22 consisting of a keyword and a communication interface 23 for inputting a telegram M and transmitting an encrypted telegram M'created by the IC card 14 to a receiving side. Further, the center side terminal 12 has a communication line 13 (13a, 13b,
13n), a communication interface 25 for receiving the encrypted telegram M'transmitted through the recording device 26, a recording device 26 such as a disk device for recording and storing the received encrypted telegram M ', and the IC card 15 mounted above. Receive encrypted message M'to IC card 15
Message M that was input to and decrypted and reproduced by this IC card 15.
A card reader / writer 27, an output device 28 such as a printer that outputs the decrypted message M, and a random number generation circuit 29 that generates a random number R used for specifying the transmission time of the message M. Composed of and.

Now, the IC card, which is the main component of this system
Reference numerals 14 and 15 are of the same kind as those introduced in, for example, Japanese Patent Publication No. 53-6491, and are configured by sealingly integrating an encryption device or a decryption device integrated as a semiconductor device therein. To be done. Among the information stored therein, specific information such as a secret key and an encryption / decryption algorithm, which will be described later, is stored in an unreadable state.

The IC card 14 is, for example, as shown in FIG.
An input / output control circuit 31 for inputting / outputting necessary information to / from the reader / writer 21, three memories 32, 33, 34, first and second
The encryption circuits 35 and 36 are included.

The random number R generated in the center side terminal 12 and given to the customer terminal 11 and the electronic message M input through the input device 22 are taken into the IC card 14 through the input / output control circuit 31. The random number R is stored in the memory 32 and given to the first encryption circuit 35, and the telegram M is given to the second encryption circuit 36. The first encryption circuit 35 generates the random number R according to the secret key KM unique to the IC card (encryption device) registered in advance in the memory 34 in a state where reading out to the outside of the device (IC card 14) is impossible. A keyword K that is encrypted and used for the encryption process of the electronic message M is created. When the secret key is KMi and the encryption algorithm of the first encryption circuit 35 is g, the keyword K is created as K = g _kMi (R). The second encryption circuit 36 encrypts the input message M according to the keyword K created in this way, and outputs the encrypted message M ′ via the input / output control device 31. When the encryption algorithm of the second encryption circuit 36 is f, the message M is encrypted as M '= f _k (M). When the encrypted telegram M'is output, the personal keyword I consisting of the ID number unique to the IC card registered in the memory 33 is output together with the encrypted telegram M '. The encryption algorithm used in the first and second encryption circuits 35 and 36 is
For example, it is composed of DES described above.

On the other hand, the IC card 15, as shown in FIG.
An input / output control circuit 41 for inputting / outputting necessary information to / from the reader / writer 27, three memories 42, 43, 44, an encryption circuit 45,
It is composed of a decryption circuit 46 and a key extraction circuit 47. The input / output circuit 41 takes in the encrypted telegram M ′ and the personal keyword I transmitted from the customer terminal 11 and the random number R generated in the center side terminal 12 into the IC card 15. Then, the random number R is registered and stored in the memory 42 and is given to the encryption circuit 45, and the personal keyword I is stored in the memory 43.
It is registered and stored in and is given to the key extraction circuit 47, and the encrypted telegram M ′ is given to the decryption circuit 46. Memory 44
Is the IC card (encryption device) 14 (14a, 14b, ~ 14)
Keys KM (KMa, KM) unique to each IC card assigned to
b, to KMn) are all registered in advance in a state in which the IC card (decoding device) 15 cannot be read out to the outside.

From the secret keys KMa, KMb, to KMn registered in the memory 44 in accordance with the personal keyword I, the key extracting circuit 47 stores the IC card (encryption device on the communication partner side) specified by the personal keyword I. The assigned secret key KMi is selectively extracted and given to the encryption device 45. This secret key KM
By inputting i, the encryption circuit 45 encrypts the random number R and creates the same keyword K in the same manner as the encryption device on the communication partner side. And the decoding circuit 46
According to this keyword K, the encrypted electronic text M'is decrypted and the electronic text M is reproduced. Decryption of the encrypted telegram M ′ is performed as M = f ⁻¹ _K (M ′) when the decryption algorithm is f ⁻¹ . This electronic message M is output from the IC card 15 via the input / output device 41. The decoding circuit 46
The decryption algorithm f ⁻¹ used in the above is different from the encryption algorithm f used in the encryption device,
That is, f ^-1 ≠ f is used.

FIG. 4 is a sequence of information communication performed between the customer terminal 11 and the center side terminal 12 which are respectively equipped with the IC cards 14 and 15 configured as described above.

When the customer who owns the IC card 14i sends the transaction message M to the center side, first, when the IC card 14i is sent to the customer terminal 11 (step 51), the card reader / writer 21 sends the random number R to the center side. Request Occurrence (Step 5
2). On the other hand, the card reader / writer 41 of the terminal 12 on the center side with the IC card 15 set (step 53)
Then, it is sequentially determined whether or not there is a request for generating the random number R (step 54), and the communication request for the certain value of the random number R generated by the random number generating circuit 29 in response to the request for generating the random number R. It is transmitted to the customer terminal 11 which is operating (step 55). By the generation request of the random number R and the communication of the random number R, the communication preparation of the electronic message M is completed.

On the customer side, the random number R is stored in the memory 32 (step 56) and the electronic message M input from the input device 22 is sent to the IC card.
Capture into 14i (step 57). This message M is encrypted as described above (step 58), and the encrypted message M'is transmitted together with the personal keyword I (step 59).

The center-side terminal 12 which has received the encrypted message M'and the personal keyword I records and stores the encrypted message M'in the recording device 26 (step 60), and at the same time, the encrypted message M'and the individual keyword. I, and the random number R described above
Take it into the IC card 15 (step 61). Then, as described above, the encrypted electronic text M'is decrypted (step 62), the decrypted and reproduced electronic text M is output via the output device 28 (step 63), and the information communication is completed.

Thus, according to such a communication network system, fraud is prevented as follows.

First, the first possible fraud is forging the encrypted telegram M'without using the IC card 14i. As described above, when DES is used as the encryption algorithm, it is possible to create an equivalent algorithm using another computer, because DES is well known. However,
The secret key KMi is known only to a limited and reliable one on the center side, and is not known to not only customers but also a large number of employees on the center side. Further, it is impossible to read this secret key KMi from the IC card 14i or the IC card 15 to the outside. Therefore, even if an encryption algorithm can be created, the encryption key K cannot be created. Therefore, after all, it is impossible to decipher the encryption process, and it is impossible to forge the encrypted telegram M '.

The next possibility is that one customer impersonates another customer and forges the encrypted telegram M ′ using his / her IC card 14k. However, even in this case, the secret key KMi registered in the IC card 14i necessary for creating the encrypted telegram M ′ cannot be known, and is different from the secret key KMk registered in the IC card 14k. After all, forgery becomes impossible.

On the other hand, it is also conceivable that the IC card 15 on the center side forges the encrypted telegram M '. However, since only the decryption algorithm f ^-1 is prepared for the IC card 15 used on the side of the center and is different from the encryption algorithm f, the encryption message M'corresponding to the message M using this algorithm is used. Is impossible to create.

In this system like this, the person who can create the encrypted telegram M'is limited to those who have the IC card 14i.
Its forgery is impossible. Therefore, only by recording and storing the encrypted electronic text M ′, a highly reliable digital signature can be realized.

By the way, FIG. 6 is a schematic configuration diagram of another communication network system based on the same technical idea. This system communicates a transaction document M from a center-side terminal 71 to a plurality of customer terminals 73a, 73b, to 73n via communication lines 72a, 72b, to 72n.

Then, the center side terminal 71 performs encryption processing using the IC card 74, and the customer terminals 73a, 73b, to 73n use the IC card 7
This is different from the above-described embodiment in that the decryption processing of the encrypted telegram is performed using 5a, 75b, to 75n.

In this case, the IC card 74 is realized by using the decryption circuit 46 of the IC card 15 shown in FIG. 3 as the second encryption circuit,
Further, the IC card 75 (75a, 75b, to 75n) is realized by using the second encryption circuit 36 of the IC card 14 shown in FIG. 2 as a decryption circuit.

Even if the network system is configured as described above, it is possible to make it impossible to forge the encrypted telegram M ′ as in the previous embodiment, and thus it is possible to obtain the same effect as in the previous embodiment. Become.

The present invention is not limited to the above embodiment. For example, the IC cards 14, 15 and the like can be realized as a portable block shape, a pencil shape, or the like. In addition, an encryption / decryption algorithm other than DES can be used. However, even in this case, the encryption and decryption algorithms need to be different from each other. Further, the IC cards 14 and 15 may have their functions realized by a microcomputer and software. In addition, the communication information is not limited to the example described above, and in short, the present invention can be variously modified and implemented without departing from the scope of the invention.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of essential parts, FIG. 2 is a configuration diagram of a customer side card, and FIG. 3 is a configuration diagram of a center side card. FIG. 4 is a diagram showing a communication sequence, FIG. 5 is a network configuration diagram, FIG. 6 is a network configuration diagram of another embodiment of the present invention, and FIG. 7 is a schematic configuration of a conventional network system. FIG. 11a, 11b, ~ 11n, 73a, 73b, ~ 73n …… Customer terminal, 12,71 ……
Center side terminal, 14a, 14b, ~ 14n, 15, 74, 75a, 75b, ~ 75n ...
… IC cards, 32,33,34,42,43,44 …… Memory, 35,36,45
...... Encryption circuit, 46 ...... Decryption circuit, 47 ...... Key extraction circuit.

Claims (8)

[Claims] 1. One or a plurality of transmitting terminals and one receiving terminal are connected via a communication line, and each of the transmitting terminals is
In a communication network system in which communication information is encrypted using an encryption device and then transferred to the reception terminal using a communication line, each of the transmission terminals is set for each encryption device. A storage unit in which a private key is stored in an unreadable manner and an encryption unit for encrypting communication information by a predetermined algorithm is sealed and integrated using at least the above-mentioned private key stored in the storage unit. And a transmitting device for transmitting communication information encrypted by the encrypting device, wherein the receiving terminal is a receiving device for receiving communication information from the transmitting terminal, and A storage unit that unreadablely stores all the secret keys defined for each encryption device, a key selection unit that selects one of these secret keys, and at least the secret key selected by this key selection unit. Using a key, with a different algorithm from the predetermined algorithm, a decryption device configured by sealingly integrating a decryption unit for decrypting encrypted communication information received by the receiving device, The communication network system, wherein the encryption unit is provided only in the encryption device provided in each of the transmission terminals. 2. The communication network system according to claim 1, wherein the encryption device and the decryption device are semiconductor devices provided inside a portable card in a sealed manner. 3. The encryption device and the decryption device are each a data encryption standard (DES).
The communication network system according to claim 1, wherein the ption standard) method is used as an encryption / decryption algorithm. 4. The key selection unit includes a code storage unit that stores a code for identifying an encryption device that stores a code for identifying the encryption device that has transmitted the encrypted and transmitted signal. The communication network system according to claim 1, wherein the secret key defined in the encryption device is selectively extracted according to the code. 5. One transmitting terminal and one or a plurality of receiving terminals are connected via a communication line, and the transmitting terminal encrypts communication information and then uses the communication line to receive the desired information. In the communication network system in which each of the receiving terminals transfers the received encrypted communication information to the terminal by using a decoding device, the transmitting terminal has a secret key defined in the decoding device. Of the communication information is encrypted with a predetermined algorithm by using a storage unit that stores all of the data in an unreadable manner, a key selection unit that selects one of these secret keys, and at least the secret key selected by this key selection unit. An encryption device configured by sealingly integrating an encryption unit for encryption, and a transmission device for transmitting communication information encrypted by this encryption device, each of the receiving terminals, Sending A receiving device for receiving communication information from a terminal, a storage unit storing a secret key determined for each decryption device in an unreadable manner to the outside, and at least the secret key stored in the storage unit are used. A decryption device configured by sealingly integrating a decryption unit for decrypting the encrypted communication information received by the reception device with an algorithm different from the predetermined algorithm, the encryption unit Is provided only in the encryption device included in the transmission terminal, and is a communication network system. 6. The communication network system according to claim 5, wherein the encryption device and the decryption device are semiconductor devices provided inside a portable card in a sealed manner. 7. The encryption device and the decryption device are each a data encryption standard (DES).
The communication network system according to claim 5, wherein the ption standard) method is used as an encryption / decryption algorithm. 8. The key selection unit includes a code storage unit that stores a code for identifying a destination decryption device that transmits an encrypted signal, and the decryption is performed according to the code stored in the code storage unit. The communication network system according to claim 5, which selectively extracts a secret key defined in the device.