JP2001357011A - User authenticating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that it is necessary to share the same random number sequence in a secret key verifying system on the transmitting side and the receiving side. SOLUTION: A transmitting side 1 is provided with a random number generating means 11 for generating a random number, an error detecting code adding means 12 for adding an error detecting code in the array of bits to the generated random number and an enciphering means 13 for enciphering the random number, to which the error detecting code is added, with a secret key, and a receiving side 2 is provided with a deciphering means 21 for deciphering the enciphered error detecting code and random number with the secret key common with the transmitting side, a logic error detecting means 22 for detecting a logic error in the bit array of the random number while using the deciphered error detecting code and an overlap error detecting means 23 for detecting the overlap error of the received error detecting code and error detecting codes received in the past.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a user authentication apparatus for verifying whether a user who has accessed a computer system that exchanges data via the Internet or the like is legitimate.

[0002]

The simplest method for verifying the validity of a user between the devices of a computer system is a password, but from the viewpoint of security strength, a verification method using a secret key cryptosystem is the most effective. is there.

In order to enhance the security of the secret key verification system, it is necessary to prevent a secret key from being stolen by a third party in the middle of an insecure transmission path, decrypted, and used later. One of the methods to prevent the secret key from being decrypted is to add a random number sequence composed of 0 and 1 to the secret key sequence by exclusive OR for each bit and transmit it. There is a method in which a key sequence is added to each bit by exclusive OR and decrypted.

The exclusive OR is an addition whose modulus is 2, and since the sum of 0 and 0 and the sum of 1 and 1 are also 0, if the same sequence is added twice by exclusive OR, the original sequence is added. Return to Therefore, if no error occurs in the middle of the transmission path, the transmitted secret key sequence can be received as it is. Also,
Since the secret key sequence sent via the transmission line is obtained by adding a random number sequence, the secret key sequence itself is random and cannot be decrypted.

[0005] When the secret key sequence is scrambled by the random number sequence in this manner, the secret key sequence is not decrypted in principle as long as the secret key sequence is kept secret, and the problem relating to security is almost solved. However, this method has a condition that a used random number sequence cannot be reused, and a different random number sequence must be used every time communication is performed. If the same random number sequence is used, the same encrypted text will be created, and it becomes possible to use the same encrypted text that has been sniffed in the past as it is, and to perform spoofing.

For this reason, the random number sequence is really random,
It must be a random number (true random number) generated based on physical noise and the like, and in order to prevent the same random number from being generated, it is necessary to set a length that allows several hundred million combinations or more.
Pseudo-random numbers generated by a computer are not suitable because the random number sequence has periodicity and the random number generation function may generate the same series depending on the setting of the initial value. In addition, generating a pseudo-random number of a safe length is not efficient because of a large amount of calculation.

[0007] In the secret key verification method, the same random number sequence must be shared each time communication is performed between the transmitting side and the receiving side, and the number of random number sequences corresponding to the traffic is stored strictly in secret. There is a problem that must be. Therefore, when a large number of messages are exchanged between a large number of users and sensors, it is practically impossible.

In order to share the same random number sequence, there is a method in which a random number sequence generated on either the transmitting side or the receiving side is transferred to the other side. It is very dangerous to put it on.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the problem that the same random number sequence in the secret key verification system must be shared between the transmitting side and the receiving side.

In order to achieve the above object, the present invention is configured as follows. That is, the invention according to claim 1 includes, on the transmitting side, a random number generating means for generating a random number, an error detecting code adding means for adding an error detecting code of a bit array to the generated random number, and a random number to which an error detecting code is added. Encryption means for encrypting with a secret key,

The receiving side has a decoding means for decoding the encrypted error detecting code and the random number with a secret key common to the transmitting side, and a bit array of the random number using the decoded error detecting code. Logic error detecting means for detecting a logic error of
And authenticating the user's validity by verifying that the bit arrangement of the received random numbers is not disturbed.

According to a second aspect of the present invention, on the transmitting side, a random number generating means for generating a random number, an error detecting code adding means for adding an error detecting code of a bit array to the generated random number, and a random number having an error detecting code added thereto Encryption means for encrypting with a secret key,

The receiving side has a decoding means for decoding the encrypted error detecting code and the random number with a secret key common to the transmitting side, and a bit array of the random number using the decoded error detecting code. Logic error detecting means for detecting a logic error of
And a duplicate error detection means for detecting a duplicate error between the received error detection code and a previously received error detection code,
A user authentication device that verifies that there is no disturbance in the bit arrangement of a received random number and no duplicate error in an error detection code to authenticate the user's validity.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a format of user authentication data according to the present invention. The user authentication data is obtained by adding a header portion H including a user number N and an authenticator A to the message M. The authenticator A is composed of a plurality of blocks to which a check code c for detecting a logical error of a bit array is added after a binary random number r.

FIG. 2 shows a block diagram of a user authentication device embodying the present invention. The user authentication device connects the transmitting side 1 and the receiving side 2 via the transmission line 3, and the transmitting side 1 is provided with a random number generating means 11, an error detecting code adding means 12, and an encrypting means 13, and 2, a decoding unit 21, a logical error detecting unit 22, and a duplicate error detecting unit 23 are provided.

The random number generation means 11 generates a binary random number r of a true random number by sampling a high-frequency waveform and thermal noise of the non-adjustable oscillator. The error detecting code adding unit 12 divides the binary random number r generated by the random number generating unit 11 into irregular blocks and divides the binary random number into a plurality of blocks. To form

The irregular position is, for example, the count value of code (1), the count value of code (0), the count value of code (1, 0) of binary random number r, or the sequential number of check code c. Is substituted into a predetermined logical expression.

The check code c is added as follows depending on the type of the error detection method. In the case of the parity check method, the check code c is added so that the number of bits of “1” is even or odd for each block. In the case of the group counting check method, a result of binary counting the number of bits of “1” in block units is added as a check code c. In the case of the cyclic code check method, a “residue” obtained by dividing a bit array polynomial by a generator polynomial in block units is added as a check code c.

The encrypting means 13 encrypts the user number N by a predetermined algorithm, and encrypts the user authentication data by adding the secret key K to the authenticator A and the message M by exclusive OR for each bit. . The secret key K is shared by both the transmitting side 1 and the receiving side 2 and is composed of digital image data such as a face photograph and digital recording data such as voice. For this reason, the key length can be made extremely long, and there are features such as little repetition.

The decrypting means 21 receives the encrypted user authentication data and translates the cipher text into the original text as follows. First, the user number N is decrypted by a predetermined algorithm, the key file F1 is accessed using the user number N as a key, and the secret key K of the user is read. Next, the secret key K read out to the authenticator A and the message M is added by an exclusive OR for each bit to decrypt the user authentication data.

The logical error detecting means 22 detects the error by checking the logicality of the bit array for each block of the decrypted authenticator A. The logic of the bit array is checked as follows depending on the type of the error detection method. In the case of the parity check method, it is checked whether the number of bits of “1” is an even number or an odd number in block units. In the case of the group count check method, the number of bits of "1" is binary-counted in block units, and it is checked whether the result matches the check code c. In the case of the cyclic code check method, a polynomial of a bit array is divided by the same generator polynomial as that of the transmitting side in block units, and it is checked whether or not it can be divided.

When the logical error detecting means 22 does not detect an error, the duplicate error detecting means 23
Is used as a key to access F2, and it is checked whether or not the same bit array exists in the check code c received in the past. As a result of the inspection, if there is an overlap, the validity of the received user is denied. This eliminates spoofing using the same cryptogram as in the past. The history file F2 is
In order to increase the memory efficiency, instead of storing the binary random number r and the check code c constituting the authenticator A as they are, only the check code c is extracted and stored.

The user authentication device embodying the present invention has the above-described configuration.
And at the same time check code c at an irregular position of random number r
Is added, encrypted with the common secret key K, and transmitted to the verifier. The verifier decrypts the received ciphertext using the secret key K shared with the user, checks the logical error of the bit array using the check code c added to the random number r, and if there is no error, verifies the user's Authenticate the validity. Further, it checks whether or not there is the same bit array in the check code c received in the past, and if there is an overlap, the validity of the user is denied.

When mutual authentication is performed, the verifier further generates a random number r, adds a check code c to an irregular position of the random number r, encrypts the random number r with a secret key K common to the user, and provides the user with the check code c. Send. The user decrypts the received ciphertext using the common secret key K, and checks a logical error in the bit array using the check code c added to the random number r. Secret key K
Since the key length can be made sufficiently long, the secret key K for performing mutual authentication and the secret key K for performing counterpart authentication use different parts. Thus, the security of the secret key K is ensured.

[0025]

As described above, the user authentication device of the present invention generates a random number and encrypts a secret key. Therefore, according to the present invention, since the secret key cannot be decrypted in principle, there is no danger of decrypting the secret key in the middle of an insecure transmission path. Further, the user authentication device of the present invention verifies that the bit arrangement of the random numbers is not disturbed, and authenticates the validity of the user.

Therefore, according to the present invention, there is no need to share a random number between the transmitting side and the receiving side, so that a disturbance operation using a random number of a secret key, which was conventionally impossible to manage a large number of random numbers, is realized. become able to. In addition, since the user can authenticate the verifier by one-way communication, the security and efficiency of the authentication are significantly improved.

Further, the user authentication device of the present invention verifies that the received error detection code has no duplicate error with the previously received error detection code and authenticates the validity of the user.
Therefore, according to the present invention, it is possible to prevent spoofing caused by directly using an encrypted text that has been eavesdropped in the past.

[Brief description of the drawings]

FIG. 1 is a format diagram of user authentication data embodying the present invention.

FIG. 2 is a block diagram of a user authentication device embodying the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission side 11 Random number generation means 12 Error detection code addition means 13 Encryption means 2 Receiving side 21 Decoding means 22 Logical error detection means 23 Duplicate error detection means A Authenticator F1 Key file F2 History file H Header part N User number M Message c check code r binary random number

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Osamu Atsumi 2-8-38 Kamizuruma, Sagamihara-shi, Kanagawa F-term (reference) 5B085 AE23 AE29 BG07 5J104 AA07 EA18 FA10 GA01 JA03 JA04 KA01 KA04 NA02 PA07

Claims (2)

[Claims] 1. A transmission side comprising: a random number generation means for generating a random number; an error detection code addition means for adding a bit array error detection code to the generated random number; and a secret key for encrypting the random number with the error detection code added. Decrypting means for decrypting the encrypted error detection code and the random number with a secret key common to the transmitting side, and a decryption means for decrypting the decrypted error detection code. A logic error detecting means for detecting a logic error in the bit array of the random numbers using the random number, and verifying the validity of the user by verifying that there is no disorder in the bit array of the received random numbers. Authentication device. 2. A random number generating means for generating a random number, an error detecting code adding means for adding a bit array error detecting code to the generated random number, and a random number to which an error detecting code is added is encrypted with a secret key. Decrypting means for decrypting the encrypted error detection code and the random number with a secret key common to the transmitting side, and a decryption means for decrypting the decrypted error detection code. Logic error detecting means for detecting a logical error in the bit sequence of the random number using the same, and duplicate error detecting means for detecting a duplicate error between the received error detection code and a previously received error detection code. A user authentication device, which verifies that there is no disorder in the bit arrangement of random numbers and no duplicate error in an error detection code to authenticate the user's validity.