JP3128567B2 - IC card system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement of a system for improving security of an IC card system. It should be noted that the term "IC" in this specification is used in a broad sense, including those with a high degree of integration, such as those generally called LSIs.

<Conventional technology> An IC card system for various credit cards and the like has a built-in IC chip having a CPU and a memory function in the card. The card is connected to a computer via a terminal, and the personal identification number is stored in the computer. To unlock the security of the card and then communicate with the computer. Such an IC card generally has a control circuit that governs security procedures and the like formed of a general-purpose CPU, and has a feature that security is higher than that of a magnetic card.

<Problems to be Solved by the Invention> However, those who are familiar with this kind of card can also decrypt security procedures and make copies. Because of this, there is no possibility of abuse,
There is a need for a card or system with higher security.

Also, improper connection between the IC card and the terminal or improper signal format may cause malfunctions.In particular, malfunctions such as loss or change of data stored in the IC card will reduce system security. It will be a major factor to hurt.

The present invention has been made in view of such problems, and has been made for the purpose of improving the security of an IC card system by reducing the possibility of unauthorized use or malfunction.

<Means for Solving the Problems> In order to achieve the above object, in the present invention, a computer, a terminal and an IC card connected to the terminal are used, and the security of the card is unlocked by a password. Then, in an IC card system that performs read / write processing between a computer or a terminal and an IC card, a cipher to be used for the next read / write is designated each time read / write processing is performed, and the designated cipher is used. If the password is not used, it will not be possible to read the next time, and the specified cipher will be formed by adding a newly determined cipher to the cipher used this time.

Specifically, provided on a computer or terminal
When reading / writing to / from the IC card, the CPU reads the encryption specified at the time of the previous read / write from the IC card,
Decryption means that enables reading / writing only when the codes match, and the encryption to be used for the next reading / writing during reading / writing with the IC card,
This is realized by providing encryption specifying means for writing to the card, and providing the IC card with storage means for storing predetermined data including the encryption in response to a command signal transmitted from the CPU.

Further, a command signal generating means for outputting a command signal to be transmitted to the IC card in the form of a serial signal is provided in the CPU of the computer or the terminal, and the command signal generating means
The reset instruction is a combination of bits in which all the bits are 0, the write instruction and the address set instruction are any combination of two bits, and the read instruction is a combination of the above reset instruction, a bit other than the write instruction and the address set instruction. Are used to compose each signal.

<Operation> In the IC card system of the present invention, in addition to a fixed password in a normal system, a cipher which cannot be read unless a designated cipher is used is also used. At the time of read / write, read / write processing can be performed only when these cipher codes match, but this cipher is used only this time, and a new cipher to be used next time is specified during processing and written to the IC card. At the next read / write, the read / write process cannot be started unless the newly designated encryption is read from the IC card.

Because this encryption is difficult to know simply by breaking security procedures or making copies,
Use of the IC card by unauthorized means is prevented.

In addition, since the encryption changes over time, even if the entire encryption is copied, if the authorized user uses the card before unauthorized use, the next encryption is specified and the copy-side card is used. Is invalidated, and unauthorized use is prevented beforehand. Further, unauthorized use is possible if the user is illegally used before a legitimate user. In this case, the next encryption is specified at the time of the unauthorized use. For this reason, if a valid user uses the card thereafter, the invalidated encryption is used as it is, so that communication cannot be performed, and the user can easily notice abnormality of the card. Therefore, it is possible to promptly take measures such as prohibition of the use of the card, and to prevent continued unauthorized use. In particular, the cipher is formed by adding a newly determined cipher to the previous cipher.
Since all the encrypted records remain, they can be useful clues in the event of an accident, and can be used to investigate the actual situation and cause of fraud.

Furthermore, when signals are exchanged between the IC card and the terminal in a non-contact manner, for example, by electromagnetic coupling of an electromagnetic coil, malfunction may occur if the electromagnetic coupling between the coils is insufficient due to improper insertion of the IC card. is there. However, in the present invention, since the command signal is configured as described above, one of the write command and the address set command in the write command and the address set command may be lost due to poor connection or the like.
May change to 0,
The command may not be readable or may be transmitted as a reset command or a read command, all of which result in a malfunction to the safe side. Therefore, a fatal malfunction such as loss or change of data stored in the IC card does not occur.

<Example> Next, an example of the present invention will be described.

FIG. 1 is a schematic configuration diagram of an IC card system. 1 is a computer installed in a system center or the like, 2 is a plurality of terminals connected to the computer 1 by a line 3, 4 is an IC card owned by each of a plurality of users, and An appropriate wired or wireless channel such as a general telephone line is used.

The computer 1 is a relatively large computer having a function of controlling the entire system.
And a function necessary for performing a predetermined operation by being interposed between the IC card 4 and the IC card 4. The CPU 21 of the terminal 2 is provided with the decryption means 22, the encryption designation means 23 and the command signal generation means 24 according to the present invention. Note that the computer 1 and the terminal 2 are also provided with a storage device, peripheral devices, and the like (not shown) as appropriate. Further, the decryption means 22, the encryption designation means 23 and the command signal generation means 24 can be provided not in the terminal 2 but in the CPU (not shown) of the computer 1.

The decryption means 22 is configured to read the cipher written at the time of the previous read / write from the IC card 4 and start reading / writing only when the cipher matches, and the cipher designating means 23 During the read / write of the data, the encryption to be used next time is randomly determined, and this encryption is
It is configured to write on the card 4.

The command signal generating means 24 is connected to the IC card 4 for reading / writing.
Various command signals required for the write process are output in the form of a serial signal, and the configuration of the command signals will be described later.

The IC card 4 is provided with an IC chip 41 having a storage means 42 and a control means 43. The storage means 42 is capable of writing and erasing data, such as an EEPROM, and the control means 43 is a logic circuit configured using a gate array for controlling the operation of the IC card 4,
The storage means 42 according to the command signal from the command signal generating means 24
It is configured so that data can be written to a predetermined address, or data at a predetermined address can be read or erased.

FIG. 2 to FIG. 4 show an example of the structure of the IC card 4 and the structure of the connecting portion between the card 4 and the terminal 2. The IC chip 41 is embedded in the card substrate 4a, and coils 44a to 44d provided on the edge of the card substrate 4a are connected to the IC chip 41. 44a is a power supply coil, 44b is a command coil, 44c is a data input coil, and 44d is a data output coil.
When they are inserted into the card insertion section, the coils are electromagnetically coupled to the coils 25a to 25d provided in the terminal corresponding to the respective coils. The coil 44a receives a driving power supply and a clock signal from the coil 25a, the coil 44b receives various command signals from the coil 25b, the coil 44c receives various data signals from the coil 25c, and the coil 44d receives data from the storage unit 42. The read data signal is sent to the coil 25d.

In FIG. 4, reference numeral 44 denotes a card side coil, and 25 denotes a coil.
The terminal side coil provided at the position where 44 is inserted
Indicates a printed circuit board on the terminal 2 side. Each of these electromagnetic coils can be obtained by, for example, a method of forming a small coil wound with a thin wire by the adhesion of a flat coil, or a method of forming a coil pattern obtained by etching a printed circuit board and a through-hole technique, and is not exposed. Covered with suitable protective material. When the card-side coil 44 is inserted to a position where it overlaps with the terminal-side coil 25, the two coils are electromagnetically coupled, so that power can be supplied and signals can be transmitted and received without contact.

Next, the general operation of this type of card system will be omitted, and the operation will be described with reference to the flowchart of FIG. 5 focusing on the characteristic portions according to the present invention.

The operation is started when the user inserts the IC card 4 into the card insertion section of the terminal 2 (step S1). First, in step S2, the password is transmitted to the computer 1,
The process proceeds to the next step S3 only when the password signals match. In this step S3, the encryption designating means at the time of the previous read / write
Only when the code designated by 23 is read from the IC card 4 and the code decryption means 22 confirms that the codes match, the security is unlocked and the device can be read / written. Thus, the process proceeds to step S4, where the read / write process is started, the required process is performed, and the process ends in step S6.

In the present invention, the encryption used in the next processing at an appropriate time during the read / write processing is the encryption specifying means 23.
Is transmitted to the IC card 4 and is stored in the storage means 42.
Is written to (step S5). The specification of this cipher is CP
The encryption signal is transmitted from U21 and stored as it is in the storage means 42.
The next encryption is formed by adding the newly determined encryption to the encryption used this time without erasing the encryption used this time.

In the case where a plurality of terminals 2 are provided as shown in FIG.
It is controlled by the computer 1 to be effective in 2, 2,.

According to the above-described operation procedure, the cipher changes chronologically each time the IC card 4 is used, so that unauthorized use by decryption or the like becomes more difficult than in the case of using only a fixed secret code.
In the unlikely event of unauthorized use, an unauthorized use cannot be performed, or an unauthorized user will not be able to use the card.

In the above operation, the various command signals sent from the CPU 21 of the terminal 2 to the IC card 4 are command signal generating means.
24 outputs in the form of a serial signal. FIG. 6 shows an example of the configuration of an instruction signal. In this embodiment, the instruction signal has an 8-bit configuration. In the reset instruction, all eight bits are 0 (L), and in the read instruction, the last bit is 1 (H). In the write instruction, the second and last bits are 1 (H), and in the two types of address set instructions, two bits are 1 (H) and the other bits are 0 (L) as shown in the figure. It is a combination.

FIG. 7 is an explanatory view of the sensitivity when the position of the card side coil 44 and the terminal side coil 25 are shifted, and the shift D of both coils.
Is larger, the degree of electromagnetic coupling is lower, and the sensitivity of signal transfer is lower as shown in FIG. Therefore, if the deviation exceeds the limit, the bit that should be 1 or H is received as 0 or L. For example, as shown as an example of a modified signal in FIG. 6, only the last bit of the write instruction is 1 or all the bits are 0.
And the last bit of the address write instruction may be 0. However, in this case, the state becomes the same as the state where the read command or the reset command is sent, or the state where the command cannot be read, so that a read or reset is performed or a predetermined operation is not performed. However, writing or address setting is not performed with a signal different from the transmitted original signal. That is,
For example, if a write or address set instruction is configured so that only one bit is 1, when the other bit of another instruction becomes 0, the write or address set instruction has the same form as the write or address set instruction. However, according to the present invention, it is possible to surely eliminate such a contingency, so that the data stored in the storage means 42 of the LC card 4 disappears or changes. Such a fatal malfunction does not occur.

<Effects of the Invention> As is clear from the description of the above embodiment, the IC card system of the present invention uses not only a fixed password but also an encryption which cannot be read unless a specified encryption is used. In addition, the designation of the cipher is performed by sequentially adding newly determined ciphers.

Therefore, it is more difficult to abuse the card by decrypting the security procedure or making a copy as compared to a system using only a password. In addition, there is an advantage that, even in the case of an unauthorized use attempt, the unauthorized use is prevented, or the abnormality can be easily detected and promptly dealt with. This makes it possible to obtain an IC card system with higher security than the above method. In particular, since a method of sequentially adding codes is adopted, all records of the codes remain, which facilitates investigation at the time of an accident such as unauthorized use and enhances the security of the system.

Further, the command signal to be transmitted to the IC card is a serial signal, all bits are 0 for a reset command, one bit is 1 for a read command, and two bits are 1 for a write command and an address set command. Each signal is constituted by a combination of bits. Therefore,
Even if a malfunction such as loss of the bit of 1 or H occurs due to misalignment of the card or disconnection of the coil, in such a case, the command signal cannot be read, or the write command or the address set command has any other form. Also, instructions other than the write instruction or the address set instruction do not take the form of the write instruction or the address set instruction even if the bit of H is missing, so that accidentality is eliminated and the stored data disappears or the other data is lost. No catastrophic problems such as change occur. Therefore, the security of the card as the external storage device is secured, and the security of the system is improved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a system, FIG. 2 is a perspective view of an IC card, and FIG.
FIG. 4 is a block diagram of an IC card and a coil portion of a terminal, FIG. 4 is a perspective view of a coupling portion between the IC card and the terminal, FIG. 5 is a flowchart of an operation procedure, and FIG. FIG. 7 is an explanatory diagram of the sensitivity at the time of signal transfer. 1 ... computer, 2 ... terminal, 4 ... IC card,
21: CPU, 22: decryption means, 23: encryption designation means, 24: command signal generation means, 25, 25a to 25d: terminal side coil, 41: IC chip, 42: storage means , 43... Control means, 44, 44a to 44d.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-99573 (JP, A) JP-A-1-48151 (JP, A) JP-A-63-259785 (JP, A) JP-A-1 304593 (JP, A) JP-A-59-212949 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06K 17/00 G06K 19/10

Claims (2)

(57) [Claims] The present invention comprises a computer, a terminal, and an IC card connected to the terminal. After decrypting the security of the card by a personal identification number, a read / write process is performed between the computer or the terminal and the IC card. IC card system that performs read / write processing every time
A cryptographic designating means for designating a cipher to be used next time by adding a newly determined cipher to the cipher used this time is provided in the CPU of the computer or the terminal, and a storing means for storing the cipher transmitted from the CPU is provided. An IC card system which is provided on an IC card and is configured to be unable to be read next time unless the designated encryption is used. 2. A command signal generating means for outputting a command signal to be transmitted to an IC card in the form of a serial signal is provided in a CPU of a computer or a terminal. Each signal is output by a combination of bits where the bit is 0, any two bits are 1 for the write instruction and the address set instruction, and each combination of the read instruction is a combination of bits other than the reset instruction, the write instruction and the address set instruction. 2. The IC card system according to claim 1, wherein the IC card system is configured to perform the following.