JPS63211046A - Portable electronic equipment - Google Patents

Abstract

PURPOSE:To make forgery of stored data difficult and to improve security by ciphering stored data based on an encipherment algorithm peculiar to a device. CONSTITUTION:When write instruction data is inputted, a control element 11 detects an area number, an area leading address, and the area size, of the write object area from the contents of an area (00) in a data memory 12. The element 11 executes the encipherment algorithm program in a program memory 13 to cipher data and writes this data in the data memory 12. In the case of read, the element 11 executes the decoding algorithm program in the memory 13 to decode and read out data. Thus, ciphering and decoding algorithms in a card are difficult to decode and the security is improved.

Description

[Detailed Description of the Invention] [J1 Ming Objective] (Industrial Application Field) The present invention is applicable to non-volatile data memory and CPU
The present invention relates to a portable electronic device called an IC card, which has a built-in IC (integrated circuit) chip having a TSM element such as U.

(Prior Art) Recently, as a new portable data storage medium, an IC card containing a built-in IC chip having a nonvolatile data memory and a control element such as a CPU has been developed. This type of IC card accesses a built-in data memory using a built-in control element, and performs input/output of necessary data in response to a request from an external device. Further, the data memory is divided into a plurality of areas, and the target areas can be accessed selectively.

-1 Now, such an IC card encrypts the transmitted data when exchanging data with an external AM, thereby protecting data from unauthorized eavesdropping on the transmission path. For example, when a data write command is input from an external device, data that has already been encrypted by the external device is accepted, decrypted, and written to the data memory, and when a data read command is input, the data is written to the data memory. It reads data stored in the computer, encrypts it, and then outputs it to an external device.

However, such conventional IC cards have the following problems. In other words, for example, if it is assumed that a so-called backer targeting an IC card intentionally reads the contents of the data memory in the card and forges the stored data, with a conventional IC card, the contents of the data memory Since the stored data has been decrypted, this action becomes easier. Furthermore, there is a requirement that the encryption and decryption algorithms within the IC card and those of the external device must be the same.

(Problems to be Solved by the Invention) The present invention solves the problem that since the stored data is decrypted as described above, it is easy to forge the stored data, and the encryption and decryption with an external device is difficult. This was done to solve the problem of having to take into account the identity of the encryption algorithm, making it difficult to forge stored data, and also taking into account the identity of the encryption and decryption algorithms with external devices. The purpose is to provide a portable electronic device that is unnecessary.

[Structure of the Invention] (Means for Solving the Problems) The present invention has a data memory section and a control section for reading and writing data to the data memory section, and selectively controls external a portable electronic device for inputting/outputting data to/from a device, the device comprising an encryption and decryption algorithm, a first means for encrypting data by the encryption algorithm; a second means for decrypting data using the decryption algorithm; and a third means for writing the input data into the data memory section after encrypting the input data by the first means when data is written in response to an external data write request. and a fourth means for decoding the data written by the third means by the second means and outputting the data to the outside when reading data in the data memory section in response to a data read request from the outside. It is equipped with the means.

(Function) Since the stored data is encrypted using an encryption algorithm unique to the portable electronic device, it becomes difficult to forge the stored data. Furthermore, since encryption and decryption are automatically performed within the portable electronic device, there is no need to consider the sameness of encryption and decryption algorithms with external devices. Therefore, the encryption and decryption algorithms within the portable electronic device are difficult to decipher, improving security.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 8 shows an example of the configuration of a card handling device used as a terminal device in a financial system or a shopping system, to which an IC card as a portable electronic device according to the present invention is applied. That is, this device enables an IC card 1 to be connected to a control section 3 consisting of a CPU or the like via a card reader/writer 2, and also connects a keyboard 4, a CRT display device 5, a printer 6, and a floppy disk device to the control section 3. It is constructed by connecting 7.

Figure 7 shows an example of the configuration of the IC card 1.
As l(r)Xm element (ta,!=,tbacPU)11
, a nonvolatile data memory 12 whose storage contents can be erased as a data memory section, a program memory 13 as a program memory section, and a contact section 14 for obtaining electrical contact with the card reader/writer 2. Of these, the part within the broken line (control element 1
1, data memory 12, and program memory 13) are composed of one IC chip and are embedded within the IC card body. The program memory 13 includes, for example, a mask RO
As shown in FIG.
1, a program P1 having an encryption algorithm, and a program P3 having a decryption algorithm are stored. Data memory 12
is used to store various data, such as EEPROM
It is made up of.

The data memory 12 is divided into a plurality of areas, as shown in FIG. 2, for example, and each area is given an area number [00, 01, . . . ]. Of these, area [00] stores the start address and area size (number of bytes constituting the area) of all areas in correspondence with the area number. For example, the start address of area [02] is address A02, and the area size is SO2 bytes.

Next, the operation in such a configuration will be explained.

First, the data write operation will be explained with reference to the flowchart shown in FIG. In a steady state, the IC card 1 is in a state of waiting for command data from the card reader/writer 2. In this state, the card reader/writer 2 has a format as shown in Figure 4, for example.
When write command data is input, the MIll element 11 decodes the write command data and stores the write target area number included in the write command data in the data memory 12.
The heading is issued from area [00]. If you can't find it,
The 11jlD element 11 outputs response data indicating that the area is unconfirmed to the card reader/writer 2, and returns to the command data holding state again. If found, the control element 11 recognizes the designated write target area of the data memory 12 based on the start address and area size of the area stored in correspondence therewith. Next, the control element 11 executes the encryption algorithm program P2 in the program memory 13.
By executing this, the write data included in the write command data is encrypted and written to the write target area of the data memory 12. When writing is completed, control element 1
1 means that the response data indicating the end of writing is sent to the card reader.
It is output to the writer 2 and returns to the instruction data waiting state.

Next, the data read operation will be explained with reference to the flowchart shown in FIG. In a steady state, the IC card 1 is in a state of waiting for command data from the card reader/writer 2. In this state, when read command data having a format as shown in FIG. 6 is inputted from the card reader/writer 2, the control element 11 decodes this read command data, and the control element 11 decodes the read command data contained in the read command data. The read target area number is indexed from area [00] of the data memory 12. If it is not found, the control element 11 outputs response data indicating that the area has not been confirmed to the card reader/writer 2, and returns to the command data holding state again. If it is found, the element 11 refers to the specified readout target area of the data memory 12 based on the start address and area size of the area stored correspondingly, reads out the data in that area, and stores it in the built-in area. It is temporarily held in RAM. Next, the control element 11
By executing the decoding algorithm program P3 in the program memory 13, the data previously held in the RAM is decoded, and the decoded data is output to the card reader/writer 2 as response data. Then, the control element 11 returns to the command data holding state again.

According to the IC card described above, the stored data in the data memory is encrypted using the card's unique encryption algorithm, so it is significantly more difficult to forge stored data than with conventional decrypted data. becomes. Furthermore, since encryption and decryption are automatically performed within the card, there is no need to consider the sameness of encryption and decryption algorithms with external devices. Therefore, it becomes very difficult to decipher the encryption and decryption algorithms in the card, and the security is significantly improved.

In the above embodiment, the portable electronic device is an IC.
7), -Card 1 is shown as an example, but the present invention is not limited to card-shaped ones, and may be, for example, block-shaped or pencil-shaped ones. Furthermore, the hardware configuration of the portable electronic device can be modified in various ways without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, the present invention provides a portable electronic device in which it is difficult to forge stored data, and there is no need to consider the sameness of encryption and decryption algorithms with external devices. can be provided.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention, and FIG. 1 shows the configuration of the program memory, FIG. 2 shows the configuration of the data memory, and FIG. 3 explains the data write operation. FIG. 4 is a flowchart showing an example of the format of write command data, FIG. 5 is a flowchart explaining the data read operation, FIG. 6 is a diagram showing an example of the format of continuous command data, and FIG. FIG. 8 is a block diagram showing the structure of the card. FIG. 8 is a block diagram showing the structure of the card handling device. 1...IC card (portable electronic device), 2.
... Card reader / writer, 11 ... Control element (IIJ control part), 12- ... Data memory (
data memory section), 13...Program memory (program memory section), Pl...Control program, P2...Encryption algorithm program, P3...Decryption algorithm program. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 WJ Figure 3 Figure 4 Figure 5 Figure 6F! ! J Figure 7 8rI! J

Claims (2)

[Claims] (1) A portable electronic device that has a data memory section and a control section for reading and writing data to the data memory section, and selectively performs input and output from the outside; Encryption and a decryption algorithm; a first means for encrypting data using the encryption algorithm; a second means for decrypting the data encrypted by the first means using the decryption algorithm; a third means for writing data into the data memory section after encrypting the input data by the first means when writing data in response to a data write request from the outside; A portable electronic device characterized by comprising: a fourth means for decoding data written by the third means and outputting the data to the outside after decoding the data written by the third means when reading data. (2) The portable electronic device according to claim 1, wherein the encryption and decryption algorithms are registered in a program memory section that stores a control program for the control section to perform control. Device.