JP2001338271A - Ic card and ic card utilizing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IC card and an IC card utilizing system of improved security. SOLUTION: An IC card 100 is provided with a microcomputer 102, having a program-processing part 104 for running a program, ROM 101 for storing the enciphered program to be run by the program-processing part 104, key storage part 105 for storing a secret key, and deciphering part 103 for deciphering the enciphered program from the ROM 101 and applying it to the program processing part 104, while using the secret key from the key storage part 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an IC card and an IC.
More particularly, the present invention relates to an IC card having a microcomputer and an IC card using system.

[0002]

2. Description of the Related Art At present, magnetic cards are widely used for various cards such as cash cards, credit cards, telephone cards, and coupons for trains, but the problems of falsification and counterfeit cards have also been highlighted.

On the other hand, security and tamper resistance, that is,
An IC card has been developed as a card excellent in withstanding unauthorized use of information, and telephone cards have already been put to practical use in Japan and used in some regions. It is expected that the transition from the current magnetic card to the IC card will proceed in the future due to cost reduction due to miniaturization of chips and the like. In particular, an IC card with a built-in microcomputer is expected to be used not only for a function as a data recording medium but also for a system that requires high security and tamper resistance such as electronic money.

In such an IC card according to the related art, a certain security level is secured.
Not safe. Therefore, as the importance of data increases, it is necessary to add a further security function to the security function provided in the current IC card.

FIG. 4 is a schematic diagram showing an example of a conventional IC card incorporating a microcomputer. The IC card 400 has a microcomputer 402 for executing a program. ROM (read only memory) 401
Stores a program to be executed by the microcomputer 402. RAM (random access memory) 40
7 is data processed by the microcomputer 402,
An external I / F via a reader / writer I / F (interface) 409 and a Logic circuit 408 as necessary
It stores data input and output from a C card reader / writer (not shown). The Logic circuit 408 is a
Data / commands input from the writer I / F 409 are converted into serial / parallel or checked, and when a command is input, the microcomputer 4
02 is instructed to read the program from the ROM 401. Microcomputer 402, ROM 401,
The RAM 407 and the Logic circuit 408 are connected to the bus 40
6 are connected. The data on the bus 406 is input / output to / from an input / output reader / writer I / F 409 via a Logic circuit 408, and is input / output to / from the outside via the input / output reader / writer I / F 409.

[0006]

The conventional IC card 400 incorporating the microcomputer 402 has a ROM 401 in which a program to be executed by the microcomputer 402 is stored. For example, a manual prober (probe) is used by a tamper. ROM 40 using
There is a possibility that program information can be obtained by measuring the potential of each bit of 1. Also, RO
By monitoring the bus 406 connecting the M 401 and the microcomputer, there is a possibility that the program in the ROM 401 can be taken out. If the program is illegally taken out in this way, there is a possibility that the program is falsified or abused to produce a forged card. As described above, in the conventional IC card 400, there is a problem that security cannot be sufficiently maintained in some cases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is an IC having excellent security.
A card and an IC card utilization system are provided.

[0008]

An IC card according to the present invention stores a microcomputer having program processing means for executing a program, and a program which is at least partially encrypted and executed by the program processing means. Program storage means, key storage means for storing key information, and key information from the key storage means,
And a decryption means for decrypting the encrypted program from the program storage means and providing the decrypted program to the program processing means.

Further, in the IC card, the encryption / decryption means is provided in the microcomputer. In the IC card, the program stored in the program storage means is encrypted using a public key of a public key cryptosystem, and the key information stored in the key storage means is a public key. This is a secret key of the encryption method. The above IC
In the card, the program stored in the program storage means is encrypted using a common key of a common key encryption method, and the key information stored in the key storage means is shared by a common key encryption method. It is the key. In the IC card, the program storage means may be a ROM, a non-volatile memory other than the ROM, or an RA.
M. Any one of M.

[0010] Also, the IC card utilization system according to the present invention comprises: a program storage means for storing a program;
A first key storage unit that stores first key information and encrypts the program in the program storage unit using the first key information; and a first key storage unit that outputs the encrypted program to the outside. IC card reader / writer having the following interface means, second interface means for inputting the encrypted program output from the IC card reader / writer, and second key information for storing second key information. Using the key information from the second key storage means and the key program from the second card storage means to decrypt the encrypted program input from the IC card reader / writer via the second interface means. An IC card having a decryption means and a microcomputer having a program processing means for executing the decrypted program. .

In the above-mentioned IC card using system, the first key information is a public key of a public key cryptosystem, and the second key information is a secret key of a public key cryptosystem. . Also, in the above-mentioned IC card utilization system, the card authentication is performed by operating while decrypting the encrypted program using the secret key stored in the second key storage means. is there.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing the configuration of an IC card according to Embodiment 1 of the present invention. In the figure, an IC card 100 includes a ROM 101, a microcomputer 102, a RAM 107, And Logic
Circuit 108 and the Logic circuit 10
A reader / writer I / F 109 connected to the data bus 106 via the input / output 8 for inputting / outputting data to / from the outside is provided. In the ROM 101, a program to be executed by the program processing unit 104 is stored after being encrypted with a public key of a public key cryptosystem. The RAM 107 stores data to be processed by the microcomputer 102 and, if necessary, a reader / writer I / F 109 and a Logic circuit 108.
External IC card reader / writer (not shown)
Stores data input / output to / from The Logic circuit 108 performs serial / parallel conversion of data and commands input / output by the reader / writer I / F 109,
In addition to performing input checking and the like, data input / output is performed between the data bus 106 and the reader / writer I / F 109. When a command is input from outside via the reader / writer I / F 109, the microcomputer 102 sends an instruction to the microcomputer 102 to read the program from the ROM 101. Key information is stored in a key storage unit 105 including a memory such as a non-volatile memory.
The key information is output to the microcomputer 102.
In the first embodiment, as the key information, a secret key of the public key cryptosystem corresponding to the public key of the public key cryptosystem described above is stored. The microcomputer 102 includes therein a program processing unit 104 for executing a program, and a secret key 10 output from a key storage unit 105.
5 is provided with an encryption / decryption unit 103 for performing decryption processing, that is, decryption of an encrypted program (hereinafter, referred to as an encryption program) read from the ROM 101. The program processing unit 104 executes the decrypted program output from the encryption / decryption unit 103. Unencrypted programs and data are stored in the decryption unit 10.
The program is input to and executed by the program processing unit 104 without passing through the program processing unit 3.

The operation of the IC card thus configured according to the first embodiment will be described below. The reader / writer I is connected to the Logic circuit 108 of the IC card 100.
When data or command is input via / F109,
The logic circuit 108 performs serial / parallel conversion. Here, when a command to execute a predetermined program is input, the Logic circuit 108 notifies the microcomputer 102 that the command has been input, and the microcomputer 102 receives this notification,
The program specified by the command is read from the ROM 101. The instruction set of the encrypted program read out from the ROM 101 and encrypted with the public key of the public key cryptosystem is transmitted via the data bus 106 in an encrypted state to the encryption / decryption unit 103 inside the microcomputer 102. Sent to The encryption / decryption unit 103 decrypts the instruction set of the encrypted program into an instruction set of a normal program using the secret key 105 of the public key cryptosystem stored in the key storage unit 105. The instruction set of the decrypted program is sent to the program processing unit 104 in the microcomputer 102 directly without being temporarily stored in a writable memory such as a RAM or via a bus. The instruction set of the program sequentially decrypted by the decryption unit in this manner is
The program is executed by the program processing unit sequentially performing the direct processing.

In the IC card according to the first embodiment, since the program used in the program processing unit 104 is encrypted and stored in the ROM 101, the program is directly stored in the ROM using a manual prober or the like. , It is not possible to extract meaningful data because the program is encrypted. That is, the contents of the encrypted program cannot be easily decrypted. Also,
Similarly, the IC card 100 is operated, and the data bus 10 is operated.
Even if the program is read from the ROM 101 via the ROM 6, the program to be taken out is encrypted, so that the result is the same, meaningful data cannot be taken out. Therefore, there is an effect that an IC card having an excellent security function can be provided.

Further, by providing the encryption / decryption unit 103 in the microcomputer 102, the encryption / decryption unit 103 is provided.
Since the wiring connecting the program processing unit 104 and the wiring is hidden in the high-density wiring in the microcomputer 102, it is difficult to find the wiring, and the decryption output from the encryption / decryption unit 103 is performed. It is possible to prevent the converted program from being taken out using a manual prober or the like.

In the first embodiment, an encryption / decryption unit 103 for decrypting an encrypted program is used.
Is provided inside the microcomputer 102,
It may be outside the microcomputer 102. However, even in this case, for the delivery of the program from the decoding unit 103 to the program processing unit 104, the decoded program is read from the data bus 106 by using a dedicated signal line without passing through the data bus 106. Need to be issued.

Also, regarding the encryption of the program in the ROM 101, it is not always necessary to encrypt all of the programs.
A part of the program, for example, only an important program may be encrypted.

In the first embodiment, the encryption method of the program is a public key encryption method here. However, a common key encryption method or another encryption method is used, and the encryption can be decrypted. Key information in key storage unit 1
05 may be stored, and in such a case, the same effect as in the first embodiment can be obtained. Generally, the processing time required for decryption in the common key encryption method is short. The public key cryptosystem has a high security function. For this reason, if priority is given to processing speed, a common key encryption method is used, and if priority is given to security,
It is preferable to use public key cryptography.

Further, in the first embodiment, the case where the encrypted program is stored in the ROM 101 has been described. However, in the present invention, as the program storage means for storing the encrypted program,
A non-volatile memory or a RAM other than the ROM may be used. Even in such a case, the first embodiment may be used.
It has the same effect as.

Embodiment 2 FIG. 2 is a block diagram showing a configuration of an IC card according to Embodiment 2 of the present invention. The IC card 200 according to the second embodiment differs from the IC card according to the first embodiment in that the encrypted program in the ROM 101 is decrypted based on the decryption program instead of the decryption unit. Encryption / decryption unit 2
03. In the figure, the same reference numerals as those in FIG.
Stores an encryption / decryption program. The encryption / decryption unit 203 in the microcomputer 202 has a ROM
By executing the encryption / decryption program stored in the key storage unit 201, the RO using the secret key in the key storage unit 105 is executed.
Decrypt the encrypted program in M101.

The operation of the IC card thus configured according to the second embodiment will be described below. IC card 20
0 Logic circuit 108, reader / writer I / F1
When a command for executing a predetermined program is input through the command 09, the Logic circuit 108 notifies the microcomputer 202 that the command has been input, and the microcomputer 202 receives the instruction and executes a decryption program. Read from ROM 201. The read decryption program is sent to the decryption unit 203 inside the microcomputer 202 via the data bus 106. Next, the encrypted program is R
Read from the OM 101 and the microcomputer 20
2 is transmitted to the encryption / decryption unit 203 in FIG. Then, the encrypted program is decrypted using a secret key read from the key storage unit 105 in the decryption unit 203 in which the decryption program is executed, and the decrypted program is stored in the program processing unit. It is sent to 104 and executed by the program processing unit 104. As described above, the IC card 200 operates by repeating the sequential decryption and execution of the encrypted program by the decryption unit 203 using the decryption program.

In the second embodiment as well, the encrypted program is decrypted by the decryption unit 203 of the microcomputer 202 using software, so that the same program as in the first embodiment is used. It works.

In the second embodiment, the decryption of the encrypted program is executed by the encryption / decryption unit 203 in the microcomputer 202. However, in the present invention,
As shown in FIG. 5, the configuration of the IC card 211 is different from that of the IC card according to the second embodiment in that a coprocessor 210 is provided outside the microcomputer 212 instead of providing an encryption / decryption unit inside the microcomputer. The configuration may be such that the processor 210 executes the encryption / decryption program in the ROM 201 to decrypt the encrypted program using the secret key from the key storage unit 105. 5, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts. However,
In this case, the delivery of the decrypted program from the coprocessor 210 to the program processing unit 104 in the microcomputer 202 is performed, for example, by using the data bus 10.
It is preferable to make it difficult to read the decoded program by using a dedicated signal line as shown in FIG.

Embodiment 3 FIG. FIG. 3 is a block diagram showing a configuration of an IC card using system according to the third embodiment of the present invention. This IC card using system uses the IC card shown in the first embodiment.
A program encrypted from an IC card reader / writer 310 outside the C card 100 is stored in the IC card 10
0, the encrypted program is decrypted by the decryption unit 103 in the IC card 100, and the decrypted program is executed by the program processing unit 104.

In FIG. 3, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and a reader / writer 310 outside the IC card 100 is used by the key storage unit 3 inside the IC card 100.
After encrypting the program used by the IC card stored in the ROM 312 using the public key 311 of the public key cryptosystem stored in the ROM 11, the encrypted program 313 is transmitted to an interface (hereinafter, I / F). 314) to the IC card 100. In the IC card 100, the transmitted encrypted program is input via the reader / writer I / F 109, and then decrypted by the decryption unit 103 using the secret key read from the key storage unit 105. The program thus executed is executed in the program processing unit 104.

In the system using the IC card according to the third embodiment, the reader / writer 310
2 is executed on the IC card 100 when the program stored in the ROM 312 of the reader / writer 310 is encrypted using the public key of the key storage unit 311 and transmitted to the IC card 100. 100, the encrypted program is decrypted using the secret key and executed.
Even if the encryption program 313 between 0 and the IC card I / F 109 leaks or is monitored on the data bus 106, it is difficult to decrypt the encryption program. Therefore, there is an effect that an IC card using system having an excellent security function can be provided.

In the third embodiment, the encrypted program sent from the reader / writer 310 is directly input to the encryption / decryption unit 103 and decrypted. RA of IC card 100
The memory may be used after being stored in a memory such as M107. In such a case, the same effect as in the third embodiment can be obtained.

In the third embodiment, the program of the reader / writer 310 is used to
The ROM 101 on the IC card 100 may be omitted if necessary.

Further, in the IC card using system according to the third embodiment, the secret key for decrypting the encryption program in the ROM 101 stored in the key storage unit 105 of the IC card 100 or the reader / writer 310 The secret key used for decrypting the transmitted encrypted program and the secret key used for card authentication of the IC card 100 may be the same key. Normal card authentication is performed by an IC card from the authentication information transmitting / receiving unit (not shown) of the reader / writer.
Information for predetermined authentication is sent to the card, and the IC card processes the information using a secret key using a Logic circuit or the like, and returns the information to the reader / writer. The authentication information transmitting / receiving unit of the reader / writer returns this information. This is performed by confirming whether or not the received data is data processed by a legitimate secret key. In many cases, this is performed only when the operation of the IC card is started. On the other hand, by using the secret key used for authentication for decrypting the encrypted program, even if the card authentication is illegally performed without using the secret key, Since the secret key is not known, the program cannot decrypt the secret key properly and the IC card 100 does not operate normally. Credibility will increase.

The key storage unit 105 stores a secret key and a common key used for encryption and decryption in the common key cryptosystem, and the encryption / decryption unit 103 of the IC card 100 decrypts the private key. In addition to decryption, decryption using a common key may be performed. That is, for example, the reader / writer 3
From 10, the common key of the common key cryptosystem encrypted with the public key of the public key cryptosystem is transmitted, and the reader / writer 310 encrypts the program in the ROM 312 using the above common key and transmits it. , In the IC card 100,
Only the common key sent from the reader / writer 310 is decrypted by the encryption / decryption unit 103 with the secret key of the public key encryption method stored in the key storage unit 105, and the decrypted common key of the common key encryption method is obtained. Alternatively, the encrypted program sent from the reader / writer 310 may be decrypted. In general, the common key encryption method requires less processing time for decryption. By doing so, the processing speed can be increased while maintaining security, and the effect of reducing the load on the microcomputer can be obtained. is there.

[0031]

As described above, according to the IC card according to the present invention, the microcomputer having the program processing means for executing the program and the program processing means having at least a part thereof encrypted are executed by the program processing means. A program storage unit for storing a program; a key storage unit for storing key information; and a key processing unit for decrypting an encrypted program from the program storage unit using the key information from the key storage unit. Means for encrypting the program, even if the program executed in the IC card stored in the program storage means is illegally read using a manual prober or the like, the program must be encrypted. To prevent program contents from being acquired by There is an effect that can provide an IC card.

Further, according to the present invention, in the IC card, the encryption / decryption means is provided in the microcomputer, so that the outside of the wiring between the encryption / decryption means and the program processing means is provided. It is possible to prevent the decrypted program output from the encryption / decryption means from being illegally taken out, and to provide an IC card with a more excellent security function.

According to the present invention, in the IC card, the program stored in the program storage means is encrypted using a public key of a public key cryptosystem, and stored in the key storage means. Key information is
Since the secret key of the public key cryptosystem is used, there is an effect that an IC card having an excellent security function can be provided.

According to the present invention, in the IC card, the program stored in the program storage means is encrypted using a common key of a common key cryptosystem, and is stored in the key storage means. Key information is
Since the common key of the common key cryptosystem is used, there is an effect that an IC card excellent in processing speed can be provided.

According to the invention, in the IC card, the program storage means may be a ROM or a ROM.
Since any one of the non-volatile memory and the RAM other than the above is used, an IC card having an excellent security function can be provided.

Further, according to the IC card using system of the present invention, the program storage means for storing the program and the first key information are stored, and the program of the program storage means is stored in the first key information. I comprising a first key storage means for encrypting using the first program and a first interface means for outputting the encrypted program to the outside.
C card reader / writer, second interface means for inputting the encrypted program output from the IC card reader / writer, second key storage means for storing second key information, Encryption / decryption means for decrypting the encrypted program input from the IC card reader / writer via the second interface means using the key information from the second key storage means; Having a microcomputer having program processing means for executing a digitized program
With the card, even if the data to be transmitted from the reader / writer to the IC card is leaked or the program executed in the IC card is illegally read by the monitor of the memory or the data bus, this program is encrypted. By doing so, it is possible to prevent the program contents from being acquired, and to provide an IC card utilization system having an excellent security function.

According to the invention, in the IC card using system, the first key information is a public key of a public key cryptosystem, and the second key information is a secret key of a public key cryptosystem. Since the key is used, there is an effect that an IC card using system having an excellent security function can be provided.

Further, according to the present invention, in the above-mentioned IC card using system, the system is operated while decrypting the encrypted program using the secret key stored in the second key storage means. Since the card authentication is performed, it is possible to provide an IC card using system having an excellent security function and to provide an IC card using system that can more accurately determine the card authentication.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an IC card according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of an IC card according to Embodiment 2 of the present invention.

FIG. 3 is a block diagram showing a configuration of an IC card using system according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional IC card.

FIG. 5 is a block diagram showing a configuration of a modification of the IC card according to Embodiment 2 of the present invention.

[Explanation of symbols]

100, 200, 211, 400 IC card 101 ROM 102, 202, 212, 402 containing an encrypted program Microcomputer 103, 203 Encryption / decryption unit 104 Program processing unit 105 Key storage unit 106, 406 Data bus 107, 407 RAM 108, 408 Logic circuit 109, 409 Reader / writer I / F 201 ROM 210 storing a program for decryption 210 Coprocessor 310 IC card reader / writer 311 Key storage unit 312 ROM storing program 313 Encrypted program 314 I / F 401 ROM

Claims (8)

[Claims] 1. A microcomputer having program processing means for executing a program, a program storage means for storing a program to be executed by the program processing means, at least a part of which is encrypted, and a key for storing key information Storage means, and decryption means for decrypting the encrypted program from the program storage means using the key information from the key storage means, and at the same time, directly providing the decrypted program to the program processing means. IC card to do. 2. The IC card according to claim 1, wherein said decryption means is provided in said microcomputer. 3. The IC card according to claim 1, wherein the program stored in said program storage means is encrypted using a public key of a public key cryptosystem, and stored in said key storage means. An IC card wherein the key information is a secret key of a public key cryptosystem. 4. The IC card according to claim 1, wherein the program stored in said program storage means is encrypted using a common key of a common key cryptosystem, and stored in said key storage means. Wherein the key information is a common key of a common key cryptosystem. 5. The IC card according to claim 1, wherein the program storage means is any one of a ROM, a non-volatile memory other than the ROM, and a RAM. 6. A program storage means for storing a program, a first key storage means for storing first key information, and encrypting the program of the program storage means using the first key information. And first interface means for outputting the encrypted program to the outside.
C card reader / writer; second interface means for inputting the encrypted program output from the IC card reader / writer; second key storage means for storing second key information; Encryption / decryption means for decrypting the encrypted program input from the IC card reader / writer via the second interface means using the key information from the second key storage means; An IC card having a microcomputer having a program processing means for executing a computerized program. 7. The IC card using system according to claim 6, wherein said first key information is a public key of a public key cryptosystem, and said second key information is a secret key of a public key cryptosystem. An IC card utilization system, characterized in that: 8. The IC card utilization system according to claim 7, wherein the card is operated while decrypting the encrypted program using a secret key stored in the second key storage means. An IC card using system for performing authentication.