JPS62216447A - Message validation communication system - Google Patents

Abstract

PURPOSE:To improve efficiency of data transfer by sending a random number with including to sending data to eliminate control of additional information so far required in the additional information system. CONSTITUTION:A transmission processing section 10 receives request for transmission of users, and provided with a transmission message interface section 4 that reserves transmission data temporarily, a random number generating section 5 that forms random numbers on request, a connecting buffer 6 that connects the random number and a message, a ciphering section 7 that forms a ciphered message from the message and random number, a data compressing section 8 that forms compressed values of the message and random number, a connecting buffer 9 that connects output information of the ciphering section 7 and the data compressing section 8, a decoding section 10 having signing function, and a transmission buffer 11 that stores output information (communication data) of the decoding section 10. Further it is provided with a transmission control section 12 that executes communication protocol in connection with the reception control section 14 of an other side transmission processing device 200. By sending the random number is place of attached information, control of attached information used in validation process is made unnecessary.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for communicating between a plurality of communication processing devices (such as a terminal device, a terminal control device, a communication control device, or a computer) that communicate via a communication line. To improve communication security,
This invention relates to a method for communicating by adding a message authentication function to communication data.

[Conventional technology]

Generally, in communication between multiple communication processing devices.

Data encryption is a means of protecting the security of communication data.
Digital signatures are used as a means of confirming the authenticity of communication partners and communication data.

Cryptography can be divided into conventional cryptography and public key cryptography.

In conventional cryptography, the encryption key and decryption key are the same, and these keys must be kept secret. DES encryption is a typical commonly used cryptography (Data Encryption S
standard federal information form
ationProcessiBS standard
ds Publication 46, 1977)
. The public key number has a different encryption key and decryption key, so even if the encryption key is made public, the confidentiality of the decryption key is not compromised. R3A encryption is a typical public key encryption (Rivest,
R, L, etal ”A Method for
Obtaining Digital Signatu
res and Public-Key Crypto
systems”, Communications
of the ACM, Vol.

21. Nα2. pp, 120-125.1978)
.

Digital signature methods can be divided into authenticator verification methods and message recovery methods, depending on the method of verifying the validity of received data (
Kenji Koyama ``Digital signature and encryption key management'', information processing,
Vo1.125. Nα6. pp, 554-560.19
84).

In the authenticator matching method, since the receiver can also generate an authenticator using a data compression device, it is possible for the receiver to forge it. Therefore, this method cannot be applied when there is a conflict of interest between the receiver and the sender. As an improved method, a method has been proposed in which a public key cryptographic decryption device is used to generate an authenticator for the sender (Kenji Koyama, "Fast and secure digital signature method using public key cryptography"). Theory of faith (D), pp.
305-312, Nα3, 1984), data transfer efficiency decreases when the length of the transmitted message is small because the data of the authenticator becomes long. For example, when using RSA encryption, the data length needs to be at least 500 bits (Rivast, R,L, etaL, "AMe
thod for Obtaining Digi
tal Signature and Public
c-Key Cryptisystems”, Go
lI+1unications of the AC
M, Vol, 21, pp, 120-126.1978
).

In the message recovery method, data transfer efficiency is not a problem, but the receiver needs to check whether the message recovered from the communication data has meaning or not, which increases the overhead associated with implementing semantic processing. . An attached information method has been proposed in which attached information (time stamp, message serial number, etc.) is added to a part of the message for the purpose of facilitating semantic processing, and a message restoration method is applied to the attached information. Using this method requires time management within the network, and using serial numbers requires serial number management, and a new procedure for managing serial numbers is also required in case a discrepancy in serial numbers occurs.

[Problems that the invention attempts to solve]

Data encryption and digital signatures are effective means for increasing the security of communication between multiple communication processing devices, but conventional authentication code verification methods and message authentication methods used for authentication processing using digital signatures are effective methods. As mentioned above, the restoration method has problems in terms of data transfer efficiency, authentication processing, etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a message authentication communication system using disposable information that has excellent data transfer efficiency, is easy to implement authentication processing, and does not require management of attached information.

[Means and effects for solving the problems] In the present invention,
By including a random number in communication data instead of attached information and sending it to the receiving side, management of attached information used in authentication processing is unnecessary.

The sending side generates an encrypted message by cryptographic processing from the sent message to which a random number has been added, adds a compressed value generated from the random number and the sent message using a data compression function, performs signature processing on this, and converts the communication data. generate. The receiving side checks whether the communication data has been forged or tampered with by checking whether the compressed value component of the encrypted message matches the decrypted random number and the compressed value generated from the message.

This communication data generation method improves data transfer efficiency compared to the conventional authenticator matching method, and the receiving side can mechanically compare values to detect whether communication data has been tampered with or forged, so semantic processing is possible. The overhead associated with implementing this can be avoided. Furthermore, since random numbers are used to generate communication data, retransmission attacks can be prevented.

〔Example〕

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

FIG. 1 is a block diagram of one embodiment of the present invention.

In FIG. 1, communication processing bags [100 and 200 are connected by a communication line 300, and the transmission processing unit 110 of the communication processing device 1100 has a transmission processing unit 110 or 220 and a reception processing unit 120 or 210, respectively. A sending message interface section 4 that accepts transmission requests from users and temporarily holds transmission data; a random number generation section 5 that generates random numbers in response to a random number generation request; A concatenation buffer 6 that concatenates random numbers and messages, an encryption unit 7 that generates an encrypted message from the message and random numbers, a data compression unit 8 that generates compressed values of the message and random numbers, and an encryption unit 7 and a data compression unit 8. A concatenation buffer 9 for concatenating output information, a decoding section 10 with a signature function, a transmission buffer 11 for storing output information (communication data) of the decoding section 1o, and a reception control section 13 of the other party's communication processing device 200. It includes a transmission control unit 2 that cooperates to execute a communication protocol.

The same applies to the transmission processing unit 220 of the communication processing device 200.

The reception processing unit 210 of the communication processing device 200 includes a reception control unit 13 and a reception buffer 14 that stores received communication data.
, an encryption unit 15 with an authentication function, a shunt 16 that separates the output of the encryption unit 15 into a compressed value component and an encrypted message component, a match detection unit 17 that checks for data matching, and a decryption unit that decodes the encrypted message. conversion section 18, distributor 19. Data compression unit 2 that generates compressed values of decoded messages and random numbers
0, and a reception message interface section 21 that notifies the user of either a "received message" or a "message error" according to the inspection result of the match detection section 17.About the reception processing section 120 of the communication processing device 100 The same is true.

Here, we will explain encryption and decryption. Now, E(
c: and m) are values encrypted using encryption method C using arbitrary information m ti-tak. D(c:k.

W) is a value obtained by decrypting arbitrary information W using encryption C using key k.

Examples of encryption (C) include DES encryption (K is the encryption key and decryption key) and R3A encryption (PK is the public key and SK is the private key).

At this time, for any information m, D (DES: K, E (DES: K, m
) ) = mD (RSA: SK, E (R';
A: PK, m) ) = m holds true.

The construction method of the R3A cipher is as follows. different prime numbers p
and q, select n, d, and e so as to satisfy the following equation.

n=pXq GCD (d, LCM (p-1), (q-1)
> ) =1e x d = 1 (mod
LCM ((p 1), (q 1)) ) here\deG
CD (a, b) represents the greatest common divisor of integers a and integer s, and LCM (a, b) represents the least common multiple of integers a and integer s.

e and n are public keys (PK), d and n are private keys (SK)
(Tazoshi's true secret information is only d), the encryption process and decryption process are E (RSA:PK, m)=m・(nod n)D
(RSA: SK, x) = w' (Ilo
d n). n determines the encrypted block length.

R5A encryption requires at least 200 decimal digits for n to ensure security, so R8A
Due to the encryption, the encrypted block length is approximately 500 bits.

Figure 2 shows the encryption part j'f using DES encryption ((a) in the same figure).
) and a decoding device ((b) of the same figure). Further, FIG. 3 shows a functional block diagram of an encryption unit rfl (FIG. 3(A)) and a decryption device (FIG. 3(B)) using R8A encryption.

The encryption method (C1) of the encryption unit 7 and decryption unit 18 is D.
Use ES encryption, R5A encryption, or other encryption methods. D
The encryption key and decryption key of the ES encryption are represented by 1, the public key of RSA is represented by PKI, the n component of PKI is represented by nl, and the private key is represented by SKI.

The encryption method (C2) of the decryption unit 10 with a signature function and the encryption unit 15 with an authentication function uses public key cryptography with a primary signature/authentication function.

E (C2: PK, D (C2: SK, w) for any information W
) = w holds true.

C2 may be R8A encryption or other encryption methods. R8
The public key of A encryption is PK2, the n component of PK2 is n2,
The private key is represented by SK2. When C1 is an R5A cipher,
It is set so that n2>nl, and the value obtained by subtracting the encrypted block length for nl from the encrypted block length for n2 is set to be equal to the data length of the compressed value.

FIG. 4 shows an example of the configuration of the data compression units 8 and 20.

The data compression unit has a function of generating output information of a certain length from input information of an arbitrary length. Input information (i, m)
The value obtained by data compression is expressed as h(i, m).

In FIG. 1, data communication from communication processing device 100 to 200 is performed as follows.

Note that the encryption method (C1) of the encryption unit 7 and the decryption unit 18 is a conventional encryption (for example, DES encryption: FIG. 2).6 The encryption method (C2) of the decryption unit 10 and the encryption unit 15 is
is based on public key cryptography (for example, R3A cryptography: Fig. 3).

(2) When the transmission message (m) is passed from the user to the transmission message interface unit 4, a random number generation request is transmitted to the random number generation unit 5.

(2) Taking this as an opportunity, the random number (i) generated by the random number generator 5 and the transmitted message (m) are concatenated on the concatenation buffer 6 to obtain concatenated data (i, m).

(2) Use the concatenated data (i, m) as input information to the encryption unit 7 and data compression unit 8. The encrypted message (m' = E (C1: Kl.

(i, m)) and the compressed value (h
' = h (i, m)) are concatenated on the concatenation buffer 9 to obtain concatenated data (h' + m').

(2) The concatenated data (h', m') is input information to the decryption unit 10 equipped with a signature function. Output information of the decoding unit 10 (α=I) (C2:SK2.(h').

m')) is written to the transmission buffer 11.

■ The contents of the transmission buffer 11 (communication data) are transmitted by the transmission control section 12 to the reception processing section 2 through the communication line 300.
10.

■ In the reception processing unit 210, communication data (α) from one communication line 300 is received by the reception processing unit 13,
It is set in the reception buffer 14.

(2) The data (α) on the reception buffer 14 is input to the encryption unit 15 equipped with an authentication function. The output information ((j, β) = E (CIPK, α)) of the encryption unit 15 is compressed using the shunt 16, and the compressed implantation S (j) in the output information is input information to the coincidence detection unit 17. , encrypted message component (β)
is input information to the decoding unit 18.

■ Communication data decoded by the decoding unit 18 ((i, m
)=D (C1: Kl, β)) is distributed using the distributor 19 to be input information to the reception message interface section 21 and input information to the data compression section 20.

■ Output information of the data compression unit 20 (h' = h (i.

m))) is input to the match detection unit 17, and a match with j input to the match detection unit 17 is detected in (■).

[Phase] When the output of the match detection section 17 becomes "match" and the received data (α) is considered to be correct, the message component ( m) is notified to the user as a "received message".

■ The output of the match detection unit 17 becomes ``mismatch''.

If the received data is deemed to have been tampered with or forged, the user is notified of a "message error" and the decoded communication data (i, m) held in the received message interface section 21 is discarded.

Message authentication communication using disposable information is executed as described above. Incidentally, when it is not necessary to encrypt the transmitted message, the encrypting section 7 and the decoding section 18 may be bypassed.

FIG. 5 shows the flow of the above processing in FIG. 1. Note that the encryption method (C1
), if public (ISS encryption (e.g. R8A encryption) is adopted, the encrypted message of ■ is m' = E (C
1: PKl, Cxp m)), the decoded communication data of (i, m) = D (C1: SKI, β).

〔Effect of the invention〕

As explained above, according to the present invention, since a random number is included in the transmission data and sent to the recipient, it is possible to eliminate the need for managing the attached information, which was necessary in the conventional attached information method. In addition, since encrypted data is generated from a compressed value and an encrypted message, it is not possible to use the conventional authenticator verification method in which an authenticator generated from a compressed value using a public key cryptographic decryption device is transmitted independently of the encrypted message. In comparison, data transfer efficiency can be improved. Also.

The receiver can detect whether or not the communication data has been tampered with or forged by comparing the compressed value (j) restored from the communication data with the compressed value (h') generated from the decoded communication data. The overload associated with the implementation of semantic processing can be avoided.

In the attached information method, the communication data for the same message changes, so it has the advantage of preventing a third party from retransmitting the same communication data at different times (referred to as a retransmission attack). Since random numbers are used for generation, retransmission attacks can be prevented.

As described above, it can be seen that the present invention has the advantage of not requiring the management of attached information in addition to the features of the conventional system. Furthermore, since the communication data is generated using a decryption unit equipped with a signature function that only the sender has, it is impossible for a third party or the recipient to forge communication data that is deemed to be correct by the match detection unit. It's impossible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a DE
FIG. 3 is a functional block diagram of the encryption device and decryption device using the S cipher. FIG. 4 is a functional block diagram of the encryption device and decryption device using the R8A cipher. FIG. The figure is a diagram showing the flow of processing in FIG. 1. 100.200... Communication processing device, 110.220... Transmission processing section, 120.210... Reception processing section 4... Transmission message interface section, 5...
Random number generator, 6, 9... Concatenation buffer, 7...
Encryption part of conventional cryptography or public key cryptography. 8.20...Data compression unit, 10...Decryption device with signature function, 11...Transmission buffer, 12
...Transmission control section, 13...Reception control section, 14...
- Reception buffer, 15... Encryption unit with authentication function, 16... Shunt filter, 17... Match detection unit, 18... Decryption unit for conventional encryption or public key encryption, 19 ...Distributor, 21...Receiving message interface section. History・2・shi・'

Claims (1)

[Claims] (1) In a system that transmits and receives data between multiple communication processing devices via a communication line, on the sending side, a random number is added to a transmitted message to generate an encrypted message, and a compressed value is generated from the transmitted message and the random number. generate,
A compressed value is added to the generated encrypted message, the ciphertext that is signed is sent as communication data, and on the receiving side, after authentication processing of the received communication data, the compressed value component and the encrypted message component are transmitted. , decrypt the encrypted message component to generate a compressed value, and compare the generated compressed value with the compressed value component separated from the communication data to check the validity of the communication data. A message authentication communication method that uses