JPH0199159A - Terminal authorizing method - Google Patents

Abstract

PURPOSE:To prevent a leakage of secrecy authorizing information to a third person by making information a different number each time of authorizing action even when it is obtained on the communication line between terminals in order that the terminal is recognized as a valid one. CONSTITUTION:In the random number generation part 33 of an IC card terminal 1, generates random numbers R that differ every when they are generated, a cipher device 34 enciphers the random number R with secrecy authorizing information R1 for ciphering key, and a number X is thus generated. A decoder 45 decodes the number X with secrecy authorizing information S2 for decoding key in order to generate a number Y, and an encoder 44 enciphers common information C2 with the number Y for ciphering key in order to generate a number Z. A decoder 35 decodes the number Z with the random number R for decoding key, and generates a number U. In case the number U and the common information C1 do not coincide with each other, the IC card terminal 1 does not authorize an IC card 2 as valid. If the bits of secrecy authorizing information S2 and S1 differ from each other, the number Y and that R must also differ from each other hence the result of the enciphering of common information is decoded with the number R for decoding key, the result will not coincide with the common information C1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for confirming (authenticating) whether or not a communicating party has valid qualifications between terminals or constituent elements constituting a communication system. In particular, the present invention relates to an IC card as a means of indicating the legitimacy of a person requesting access to a computer system and communication between IC card terminals, and relates to a method of authenticating a counterparty between these terminals.

BACKGROUND OF THE INVENTION In recent years, with the spread of plastic cards (IC cards) with built-in computing devices and storage devices, there has been an increasing need to protect IC cards or IC' card terminals (hereinafter referred to as terminals) from counterfeiting. There is. To this end, secret information unique to the system consisting of the IC card and terminal is secretly stored in the IC card and terminal, and communication between the IC card and the terminal allows each party to confirm that the other party has the correct secret information. Technology has been developed to authenticate the other party by This example is JP-A-62-6
5168. In this embodiment of the prior art, card-specific data IA is stored in the IC card in advance.
Then, this data IA is processed by the card issuer's encryption procedure E()
Data E (IA) encrypted with is stored. It is also assumed that the card-specific data IA is a concatenation of three parts X, Y, and Z. Now, when you insert the IC card into the terminal,
Mutual authentication between the IC card and the terminal is performed in the following procedure.

(1) Send E(IA) from the IC card to the terminal.

(2) The terminal decodes E (IA) using decoding procedure D() and obtains decoded data IA' = D (E (IA)).

The decoded data IA' is a concatenation of X', Y' and Z'.

(3) The terminal transmits X' of the decoded data IA' to the IC card side.

(4) The IC card compares X and X'. If they do not match, the IC card determines that the currently connected terminal is not legitimate and ends the authentication operation.

(5) If X and X' match, the IC card determines that the currently connected terminal is legitimate. Then, X, Y, and Z are transmitted to the terminal side.

(6) The terminals that received this are X and X', Y and y'
, z and Z′ respectively. Only when all of these match, the terminal determines that the currently connected IC card is legitimate.

After the terminal and the IC card control unit mutually authenticate the signal to that effect, the user's identity is verified by comparing the PIN code entered by the IC card user with the PIN code secretly stored in the IC card. Then, proceed to the actual trading operation.

However, in the mutual authentication process described above, the data transmitted and received between the IC card and the terminal is the same each time the IC card is used. Therefore, if person B with malicious intent is in a position where he can freely use a terminal, he can add a device to the communication line between the terminal and the IC card to eavesdrop on communication data. When user A who is attempting to use the device performs the mutual authentication operation described above, he obtains E (IA) in step (1) above, and obtains x, y, and z by eavesdropping in step (5). can do. B, who obtained these data, uses another I
By writing the above data to the C card, the I
It becomes possible to forge the C card and impersonate user A.

In view of this, the present invention provides a method for authentication of a terminal that does not leak useful or secret information to the system even if a third party intercepts and obtains information for recognizing that the terminal is legitimate. The purpose is to provide a method.

Means for Solving the Problems The present invention provides a first and second terminal having first and second secret authentication information and first and second common information, respectively;
A first terminal generates a random number, generates a second number by encrypting the random number using the first secret authentication information as an encryption key, sends the second number to the second terminal, and 2
The terminal generates a third number by decrypting the second number using the second secret authentication information as a decryption key, and encrypts the second common information using the third number as an encryption key. thereby generating a fourth number, sending the fourth number to the first terminal, and encrypting the first common information at the first terminal using the random number as an encryption key. verifying equality and thereby authenticating said second terminal; If the confirmation is not performed, the second terminal is determined to be an imposter, and communication is stopped.

Effect of the present invention Through the above-described process, even if a third party intercepts and obtains information for recognizing that a terminal is legitimate on the communication path between the first and second terminals, the information will not be stolen. Since it is only a second number or a fourth number, and they are different numbers for each authentication operation, information useful or secret to the system, i.e., secret authentication information of the first and second terminals, cannot be transmitted to the third party. It will not leak.

Embodiment FIG. 1 shows an environment in which the present invention is optimally used. In Figure 1, 1 is an IC card terminal, 2 is an IC
It's a card. The IC card terminal 1 has a processing bag fill, which accesses the storage device 12 and input/output circuit 1.
It is connected to the outside via 3. Further, the processing device 11 can be connected to an external computer system (not shown) via a keyboard 14, a display device 15, and a communication line 16. The IC card 2 is detachably connected to the IC card terminal 1. The IC card 2 has a processing device 21 that accesses the memory 2 and is connected to the outside via an input/output element 23.

It is now assumed that the IC card terminal 1 is connected to an external computer system for financial services via the communication line 16. It is assumed that when the IC card 2 is coupled to the IC card terminal 1, the owner of the IC card 2 can receive a certain specific financial service. At this time, if I
If the C card 2 is a fake and it is possible to fraudulently receive financial services, the provider of this financial service will suffer a large economic loss. In order to avoid this situation, the financial service provider needs a means to confirm that the IC card 2 is legitimate, with the assumption that the IC card terminal 1 is legitimate. Therefore, before information is exchanged between the IC card 2 and the IC card terminal 1,
The IC card terminal 1 authenticates the authenticity of the IC card 2 as follows. Figure 2 shows IC card terminal 1
Authentication method when authenticating IC card 2 As shown in Figure 2, IC card terminal 1 and IC card 2
Each stores secret authentication information and common information. That is, the IC card terminal 1 stores the first secret authentication information S1 in the first secret authentication information storage section 31, and the IC card 2 stores the second secret authentication information S2 in the second secret authentication information storage section 41. has been done. If both the IC card terminal 1 and the IC card 2 are genuine, Sl and 82 are equal, and both are information known only to the financial service provider. Further, the first common information C1 is stored in the first common information storage section 32 of the IC card terminal 1, and the second common information C2 is stored in the second common information storage section 42 of the IC card 2. I
If both C card terminal 1 and IC card 2 are genuine,
C1 and C2 are equal and both are information known to all terminals related to financial services. The IC card terminal 1 also includes a first encoder 34 and a first decoder 35. Furthermore, 33 is a random number generation unit that generates random numbers, and 36 is a comparator that outputs whether or not two pieces of input information match. On the other hand, the IC card 2 has a second encoder 34 and a second encoder 34.
There is a decoder 35.

Regarding the IC card terminal and IC card system configured as described above, the operation of the IC card terminal 1 to authenticate the IC card 2 will be described next.

(1) A random number R is generated by the random number generator 33 of the IC card terminal 1. This random number needs to be a different number each time it is generated.

(2) Then, the first encoder 34 generates a second number X by encrypting the random number R using the first secret authentication information S1 as an encryption key.

(3) This number X is then sent to the second decoder 45 of the IC card 2 via the ICC card terminal 2 input/output circuit 13, the communication path 50, and the input/output circuit 23 of the IC card 2.

(4) The second decoder 45 receives the second secret authentication information S.
The third number Y is generated by decoding the number X sent as described above using 2 as the decryption key.

(5) The second encoder 44 generates a fourth number Z by encrypting the second common information C2 using the number Y as an encryption key. Input/output circuit 2
3, communication path 50, and 1. Input/output circuit 13 of C card terminal 2
The data is sent to the first decoder 35 of the IC card terminal 1 via the IC card terminal 1.

(7) The first decoder 35 decodes the number Z sent as described above using the random number R as a decryption key, thereby decoding the number U.
generate. This number is then input to one side of the comparator 36, and the common information C1 is applied to the other input.

(8) If the number U and the common information C1 do not match, the IC card terminal 1 does not recognize the IC card 2 as legitimate. Then, the authentication process ends with the result that "authentication was successful". Because, if IC card 2
If the second secret authentication information S2 of the IC card terminal is different from the first secret authentication information S1 of the IC card terminal, the third number Y should naturally be different from the first number R.
This is because if the result of encrypting the common information using the number Y as the encryption key (the fourth number Z) is decrypted using the first number R as the decryption key, the result naturally does not match the common information c1.

On the other hand, if the number U and the common information c1 match, the IC card terminal 1 authenticates the IC card 2 as legitimate. Then, the authentication process ends with a result indicating that it has been authenticated.

In order to guarantee the safety of this entire system, the IC card terminal 1 must authenticate the IC card 2 as described above, and then the IC card 2 must authenticate the IC card terminal. This purpose can be achieved by exchanging the roles of the IC card terminal and the IC card in the process described above.

As described above, in this example, through the process described above,
Even if a third party intercepts and obtains information for recognizing that the terminal is legitimate on the communication path between the IC card and the IC card terminal, it will only be number X or number Z. That is, although these numbers are different each time an authentication operation is performed, information useful or secret to the system, that is, secret authentication information of the IC card and IC card terminal, will not be leaked to the third party.

In addition, in this embodiment, in order to check whether the second terminal has the same secret authentication information as the first terminal, the fourth number Z is decrypted using the random number R as the decryption key, and the result (U) is It was determined whether the information matched the first common information C1 or not. The following determination method, which is different from this, is also possible. That is, it is checked whether the result of encrypting the first common information C1 using the random number R as the encryption key and the fourth number Z match. It is clear that even in this manner it is possible to determine whether the second terminal has the same secret authentication information as the first terminal. Moreover, even if this configuration is used, the above-mentioned effects can be similarly exhibited.

As described in detail, according to the present invention, information for recognizing that a terminal is legitimate is transmitted over a communication path between terminals.
Even if a third party intercepts and obtains the numbers, the numbers are different for each authentication operation, so information useful or secret to the system, that is, secret authentication information for each terminal, will not be leaked to the third party. . Therefore, the practical effects of the present invention are significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for implementing a terminal authentication method according to an embodiment of the present invention, and FIG. 2 is a block diagram of an example of hardware related to the terminal authentication method according to an embodiment of the present invention. 1...IC card terminal, 2...IC card, 31.
...First secret authentication information, 33...Random number generator, 36
...Comparator, 41...Second secret authentication information. Name of agent: Patent attorney Toshio Nakao and one other person Figure 2

Claims (1)

[Claims] a first and a second terminal have first and second secret authentication information and first and second common information, respectively; the first terminal generates a first number; and the first secret authentication. generating a second number at the first terminal by encrypting the first number using information as an encryption key; sending the second number to the second terminal; and performing the second secret authentication. generating a third number at the second terminal by decrypting the second number using the information as a decryption key; and encrypting the second common information using the third number as an encryption key. generating a fourth number at the second terminal; sending the fourth number to the first terminal; using the first common information and the first number at the first terminal; The fourth number specifies the first common information as the first common information.
A terminal authentication method characterized in that the second terminal is authenticated by confirming that the number is the same as the number encrypted using the encryption key, and thereby authenticating the second terminal.