JPH06282228A - Code number verification device - Google Patents

Abstract

PURPOSE:To obviate the storage of either of secrete data itself or enciphered secrete data in a device, and yet provide an effect similar to a case where the enciphered data is stored therein, by judging the data to b genuine secrete data through the proper decoding of a suitable cryptotext, using the secrete data as a cryptographic key. CONSTITUTION:A code number CI gained from a decoding process is used as a cryptographic key, and a code number judgement sentence 36 enciphered using the number CI a key is decoded in a decoding circuit 34. Then, when a means 38 for judging proper decoding identifies that the text 36 is properly decoded, the number CI is judged to be genuine and belong to a user. When the decoding of the text 36 is judged to be improper, the code is again entered in the specified circuit and an IC card is regarded as invalid, if the code is over the capacity of the circuit. Regarding the plain text of the code number judgement sentence 36 enciphered using the code CI as a key, the decoding thereof is judged to be proper, for example, when text length is 8 bytes and the content of the sixth byte is equal to the content of the first byte multiplied by the content of the third byte.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a confidential data (personal identification number) verification method for verifying confidential data (personal identification number, etc.).

[0002]

2. Description of the Related Art A data processing method using confidential data (personal identification number or the like) includes a data transmission device for transmitting data to a data processing device. Then, the processing of the data composed of the data of the routine nature and the confidential data is performed. In such a scheme, sensitive data (such as a personal identification number) is commonly used to allow interaction between a data processing device and an operator via a data transmission device. There are many examples of using the data processing method of this nature, and the examples are shown below. In addition, "IC card development and mechanism" by Katsushi Sunagawa and Hiroyuki Kikui (Industrial Research Committee) and Japanese Patent Publication No. 61-43750 are cited. In the following description, in order to avoid misunderstanding, the data referred to as confidential data (personal identification number, etc.) is defined as data used as a key for opening / up the dialogue between the data processing device and the operator. . However, the confidential data (personal identification number, etc.) referred to here includes a password, an encryption key, a front door, a door key of a car, etc. used when accessing a computer, as described later.

(1) Magnetic Card In the magnetic card (bank card with magnetic stripe) method, personal identification data for identifying the user on the magnetic stripe (instead of personal identification data, personal identification data is used by a so-called encryption method). Then, the encrypted data may be recorded on the magnetic stripe, and the process of reading out the personal identification data (or decrypting the encrypted personal identification data on the terminal) is performed. Then, it is checked whether it matches the personal identification number entered by the user using the keyboard of the terminal. However, in this case, since all the data on the magnetic stripe is read by the magnetic head, the personal identification data may be immediately read by an unauthorized person and the personal identification number may be found. In addition, even if the secret code data is further encrypted by the encryption method and recorded, the data on the magnetic stripe is directly read by the magnetic head as it is, so many illicit persons have many clues for decrypting the encryption method. This leads to the provision of the personal identification number, and eventually the personal identification number is easy to be detected. As another method of identifying a user when a magnetic card is used, only the user account number is recorded on the magnetic stripe, and the user's personal identification data is controlled by the host that controls the terminal. There is a method of separately storing only in the data memory of the computer. However, in this method, a system for identifying the user is developed mainly by the host computer, and there is a drawback that the system cost becomes high.

(2) In the case of IC card On the other hand, if the personal identification data cannot be leaked to the outside of the IC card, an illegal person cannot read the personal identification data from the IC card. That is, in this IC card, the secret code data can be hidden inside the IC. In this case, it is not necessary to store the personal identification data in the data memory of the host computer. That is, it is not necessary to suffer from the host computer for the identification of the user himself, and the identification of the user himself can be achieved only if there is a terminal device. So-called local processing is possible. The ability to perform local processing while satisfying information security is a major advantage of IC cards over magnetic stripe cards.

In the above-described method, the keyboard usable by the operator is a "public" device or "public" device used by a very large number of people, but in order to use it effectively. Is only possible after the correct confidential data (PIN) has been transmitted. However, an unqualified person or criminal can
Using the space separated from the C card, there is a possibility that a certain user discovers confidential data (personal identification number) of data to be subsequently transmitted to the IC card. Japanese Patent Publication 61-4
No. 3750 describes a method using encryption with higher security. In other words, in this method, the personal identification number data entered by the user with the keyboard of the external device is not directly output on the transmission line from the external device to the IC card as it is, and a different encryption key is used for each trial of personal identification. Different encrypted data is output on the transmission line. At one trial to verify the identity, both the IC card and the external device use a common encryption key C ₁ ,
Mutually encrypt messages and decrypt ciphertexts. At the next attempt to verify the identity, both the IC card and the external device will have a different encryption key C from the previous one, but the common encryption key C.
_{Use 2} to encrypt the message and decrypt the ciphertext again. In this way, a message (currently) is applied through a method in which a ciphertext is placed on a transmission line connecting an IC card and an external device, and a cryptographic key for creating the ciphertext is different for each trial. In that case, a message called a personal identification number is exchanged.

As a result, even if an illegal person watches the transmission line and obtains a large amount of ciphertexts exchanged between the IC card and the external device, the ciphertext creation cipher keys are successively generated for each communication attempt. As it is changed, it becomes extremely difficult for an illegal person to guess the user's personal identification number and detect it. FIG. 3 is a functional block diagram 10 of a data processing system using an IC card using the cryptographic method. Using FIG.
The method of Japanese Patent Publication No. 61-43750 will be described below. (Process 1) The data processing device 12 designates the encryption key C _i used for encryption / decryption to the external device 14 and the IC card 16 for each trial of the identification. (Process 2) Next, using this encryption key C _i , the personal identification number CI input by the user to the keyboard 24 is encrypted in the encryption circuit 20, and the combined signal (C _i *
CI). Then, this composite signal is guided to the decoding circuit 26 in the IC card via the transmission line 18. (Step 4) In the decoding circuit 26, the same C _i
The code number is decoded from the combined signal using. This decryption action is C _i ^-1 * (C _i * CI) = CI
Abbreviated. (Step 5) The personal identification number CI obtained by decryption and the personal identification data CI that has been hidden in advance in the memory 30 of the IC card are input to the comparison circuit 28 in the IC card. If they match as a result of the comparison, it is confirmed that the user is the user himself. If they do not match, re-input up to the specified number of times, and if the specified number is over, the IC card will be invalid. (Process 6) After confirming the identity of the user, a service system for deposits and payments consisting of the data processing device 12, the IC card 16 and the external device 14 opens up.

The basic technology of the IC card up to the present is summarized below. 1) Embed the IC circuit in the card. Confirm the truth of the card,
In addition, the personal identification of the user is confirmed by the PIN code method. 2) Uses PROM as the IC circuit embedded in the card.
Data is input from an external device and recorded in the PROM if necessary. Record depreciation and depreciation on the card. 3) The IC memory of the card is divided into areas that are difficult to access. That is, various areas are set according to the access from the external device as follows. B) Unreadable / writable area b) Readable / unwritable area c) Readable / writable area And these divisions were achieved by providing a logic processing electronic circuit inside the card. 4) A password comparison and verification circuit is installed in the card. 5) Introduces a cryptographic transmission system for signal transmission / reception between the card and external device. 6) A microprocessor that performs logical processing according to a program is installed in the card. 7) Record the number of mistakes made by the user in inputting the personal identification number in the PROM of the IC card.

[0008]

However, in the confidential data verification device described above, (1) In order to prevent confidential data (personal identification number, etc.) from leaking out of the IC card, a special, logical It is necessary to provide processing electronics. (2) In the case of the above (1), it is difficult to change confidential data (personal identification number, etc.). (3) Confidential data (PIN, etc.) itself, or
Since the encrypted personal identification number is stored in any of the devices, there is a possibility of eavesdropping on the personal identification number. The present invention has been made in order to solve such a problem, and the confidential data (personal identification number or the like) itself or the encrypted confidential data (personal identification number or the like) is stored in any device. It is an object of the present invention to provide a confidential data verification device which has the same effect as storing confidential data (personal identification number, etc.).

[0009]

According to a first aspect of the present invention, there is provided a confidential data verification device, which has a confidential data judgment statement encrypted in advance to verify that the confidential data is authentic. As the encryption key, the encrypted confidential data judgment text is decrypted by the decryption means, the decryption state is inspected, and if the decryption is correct, it is determined that the confidential data is authentic. It is characterized in that it includes means for determining whether or not it is high. The confidential data verification device according to claim 2 decrypts the encrypted confidential data determination text by a decryption means, checks the decryption state using only the plaintext confidential data determination text, and decrypts correctly. If the confidential data is authentic, it is determined that the confidential data is authentic, and the confidential data is correctly decrypted. The confidential data verification device according to claim 3 decrypts the encrypted confidential data determination text by a decryption means, and decrypts the encrypted confidential data determination text and the pre-stored encrypted confidential data determination text. By matching,
It is characterized in that it includes means for determining whether it has been correctly decoded, for verifying that it has been correctly decoded. Claim 4
The confidential data verification device described is characterized in that the confidential data is a personal identification number of an IC card. The confidential data verification device according to claim 5 is characterized in that the confidential data is a personal identification number of a magnetic card. The confidential data verification apparatus according to claim 6 is characterized in that the confidential data is a computer access password. The confidential data verification device according to claim 7 is characterized in that the confidential data is a secret code for opening and closing a door. The confidential data verification apparatus according to claim 8 is characterized in that the confidential data is an encryption key.
The confidential data verification device according to claim 9 is characterized in that the confidential data is a device activation password.

[0010]

In the confidential data verification device according to the present invention, neither the confidential data (personal identification number or the like) itself nor the encrypted confidential data (personal identification number or the like) is stored in any device, Moreover, the same effect can be obtained when confidential data (personal identification number, etc.) is stored. In other words, when the confidential data judgment sentence encrypted with the confidential data (PIN etc.) as the encryption key is decrypted by the decryption means, and it is correctly decrypted based on the plaintext confidential data determination sentence, Judge that confidential data (PIN, etc.) is authentic.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 is a functional block diagram of a device for verifying confidential data (personal identification number, etc.), and FIG. 3 shows a functional block diagram of a data processing method by an IC card using an encryption method. FIG. 3 is a functional block diagram in which the verification device 32 is configured according to the present invention, and verifies confidential data (personal identification number, etc.). FIG. 2 is a confidential data (PIN code, etc.) determination text that has been encrypted in advance by the confidential data (PIN code, etc.), and is an example of the PIN code determination text 36 encrypted using the CI of FIG. 2 as a key. . Now, the operation of the confidential data (personal identification number) verification device of the present invention will be described with reference to FIGS. The prior art (Process 5) is improved as follows. (Step 5) The personal identification number judgment text encrypted with the personal identification number CI obtained by decryption as the encryption key and the CI as the key.
Is decoded by the decoding circuit 34, and when it is judged by the means 38 for judging whether it was correctly decoded, it is confirmed that the CI is authentic and the user himself / herself. When it is determined that the IC card has not been correctly decrypted, the IC card is re-input up to the specified number of times, and the IC card is invalidated if the specified number of times is exceeded. (Process 6) After confirming the user himself / herself, a service system for deposits and payments including the data processing device 12, the IC card 16 and the external device 14 opens up.

FIG. 2 shows an example of the plaintext of the password identification sentence 36 encrypted with the CI as a key. Since the length is 8 bytes and the content (70) of the first byte and the content (2) of the third byte are equal to the content (140) of 6 bytes, it can be determined that the decoding is correctly performed. As described above, the correct decryption can be determined using only the personal identification number determination text 36 encrypted with the CI as a key. Of course, the PIN judgment text encrypted with the CI as a key
It is possible to store 36 plaintexts and verify the agreement with the decrypted plaintexts, but the security becomes weaker. Since decrypting the ciphertext will eventually lead to finding the encryption key, this method that uses the PIN as the encryption key is the most secure compared to the conventional method of encrypting and storing the PIN. It's an expensive method. What can be used by the present invention as confidential data (personal identification number, etc.) is I
Wide range of passwords such as C-cards and magnetic cards, passwords used for computer access, door-entrances at homes, hotel rooms, doors of cars, etc. Available at.

[0013]

As described above, according to the present invention, the confidential data (personal identification number, etc.) is used as an encryption key to properly decrypt an appropriate ciphertext to determine the confidential data (personal identification number, etc.). Therefore, confidential data (PIN, etc.) itself or encrypted confidential data (PIN, etc.)
None of them are stored in any of the devices, and moreover, it is possible to obtain the same effect as if the confidential data (personal identification number or the like) is stored.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a device for verifying confidential data (personal identification number, etc.).

FIG. 2 is a confidential data (personal identification number, etc.) determination text encrypted in advance by confidential data (personal identification number, etc.).

FIG. 3 is a functional block diagram of a data processing method by an IC card using an encryption method.

[Explanation of symbols]

 10 data processing method 12 data processing device 14 external device 16 IC card 18 transmission line 20 encryption circuit 22 lines 24 keyboard 26 decryption circuit 28 comparison circuit 30 secret code CI 32 built in the IC card confidential data (password etc.) Verification device 34 Decryption circuit 36 Personal identification number determination text encrypted with CI as a key 38 Means for determining whether or not decryption is correctly performed

Claims (9)

[Claims] 1. A confidential data verification device for verifying whether or not confidential data is authentic has a confidential data judgment text encrypted in advance, and the confidential data judgment text encrypted using the confidential data as an encryption key. Is decrypted by the decryption means, the decryption state is inspected, and if it is decrypted correctly,
A confidential data verifying apparatus, comprising means for determining whether the confidential data is authentic and determining whether the confidential data has been correctly decrypted. 2. The encrypted confidential data judgment text is decrypted by a decrypting means, and the decryption state is inspected using only the plain text confidential data judgment text. 2. The confidential data verification device according to claim 1, further comprising means for determining whether the confidential data is authentic and determining whether the confidential data has been correctly decrypted. 3. The encrypted confidential data judgment sentence is decrypted by a decryption means, and the plaintext confidential data judgment sentence and the prestored plaintext confidential data judgment sentence are matched, so that 2. The confidential data verification device according to claim 1, further comprising means for verifying that the data has been decrypted and determining whether the data has been decrypted correctly. 4. The confidential data verification device according to claim 1, wherein the confidential data is a personal identification number of an IC card. 5. The confidential data verification device according to claim 1, wherein the confidential data is a personal identification number of a magnetic card. 6. The confidential data verification apparatus according to claim 1, wherein the confidential data is a computer access password. 7. The confidential data verification device according to claim 1, wherein the confidential data is a secret code for opening and closing a door. 8. The confidential data verification device according to claim 1, wherein the confidential data is an encryption key. 9. The confidential data verification device according to claim 1, wherein the confidential data is a device activation password.