JPS63301388A - Ic card - Google Patents

Abstract

PURPOSE:To perform the erasure of information with high secrecy after a prescribed time, by providing an area to record discrimination information of the erasure of data after the lapse of the prescribed time from the storage of the data corresponding to the data in a memory. CONSTITUTION:The data storing area 3 of an IC card 1 is divided into an ordinary data storing area 3a and an erase data storing area 3b. In the area 3b, the data are stored in the form of (Ak.Ak+1) which form the pairs of addresses (An.An+1), (An+2.An+3),..., and erase data SDl is recorded in the address Ak, and a time Tl to be erased, that is, a time in which a preserving time is added on a write time is recorded in the address Ak+1. In such a way, readout is disabled if the time Tl of the Ak+1 in the area 3b is the time before the present time, and furthermore, the data is erased. By recording the data with secrecy in the area 3b, the secrecy can be held.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an IC card having a storage area for determining whether or not to erase data stored for a predetermined period of time.

[Conventional technology]

Recently, ICs such as CPU and memory are built into cards.
Cards have been proposed and are gaining popularity. This IC card is
Generally, a non-luminous programmable memory is provided, and by storing various information as data in this memory, long-term data storage can be performed. Furthermore, progress has been made in the development of rewritable memory, making it easier to update the data stored in memory, making it possible for IC cards themselves to be used for recycling.

Access to data stored in the memory of such an IC card is generally controlled by a CPU or an external device based on a built-in or external program. Further, depending on the application program, there are many configurations in which a logical or physical recording position is designated and managed in the memory of the IC card according to a predetermined interpretation on the program. Therefore, in order to record the necessary information as data, define in advance one data storage area according to the information content in the memory of the IC card, and specify this data storage area nine in the application system. You will be reading and reading information.

[Problem that the invention seeks to solve]

However, in the conventional IC card with the above configuration, the data stored in the data storage area in the non-luminous read/write memory is stored until it is erased or overwritten with other data after the data is recorded. . Therefore, confidential information is stored on the IC card, and this
If you lose your C card, confidential information will be permanently stored in the IC card, and there is a high possibility that the confidential information will be stolen by a third party who finds this IC card. There was a problem.

This invention was made in order to solve the above-mentioned problems, and it is possible to obtain an IC card that stores highly confidential information in a manner that prevents the information from being read after it has been stored for a predetermined period of time. purpose.

[Means for solving problems]

The IC card according to the present invention includes a storage area in the memory that can store, in correspondence with the data, determination information that can determine whether or not the data should be erased after a predetermined period of time has elapsed from the data storage time.

[Effect]

The discrimination information that is important to this invention indicates whether data needs to be erased after a predetermined period of time has elapsed from the storage time, so by decoding this discrimination code, only data that needs to be erased can be erased for a predetermined period of time. It can be deleted after the elapsed time.

[Embodiment] FIG. 1 is a system configuration diagram of an IC card which is an embodiment of the present invention. In the figure, 1 is an IC card having a non-luminescent programmable memory, 2 is an external device,
It has a reader/writer mechanism 2a for reading and writing data into and from the memory of the IC card 1, a control mechanism 2b for the IC card 1, and the like.

FIG. 2 is a memory configuration diagram of the non-luminous programmable memory in the IC card 1 shown in FIG.

In the figure, 3 is a data storage area, 3a is a normal data storage area, 3b is an erase data storage area, and the normal data storage area 3a has addresses A1 to A. -1, the erase data storage area is allocated to addresses A ~ 〇Ig.

The normal data storage area 3a stores data D1 to Dn-1 corresponding to each address A1 to An-1. On the other hand, in the erased data storage area 3b (Ao).

A), (A, A),...
・(A, An+I n42
n+3 m-1,) is stored in the format of (A, A) paired with k k+1 , the erase data SD is stored at address Ak, and the erase data SD is stored at address A at +1 time T. , is recorded.

FIG. 3 is a flowchart showing a processing procedure when writing data to an IC card having the above-described memory configuration;
The write operation will be explained below with reference to the same figure. In step S1, if the input person specifies whether the data to be input is erased data or normal data and specifies erased data,
In step S2, data SD is written to the empty address Ak of the erased data storage area 3b, and in step S3
Then, the erase time T, which is the current time plus a predetermined storage time, is written to the address Ak+1. On the other hand, if normal data is specified in step S1, data D is written to free address /J (i-1 to n-1) of the normal data storage area 3a in step S4.

Satoshi FIG. 4 is a flowchart showing the processing procedure when reading data from the IC card having the memory configuration shown in FIG. 2, and the reading operation will be explained below with reference to the same figure. In step 811, it is determined whether the accessed address Aj is the normal data storage area 3a or the erased data storage area 3b, and if this address Aj is the normal data storage area 3a, the contents of this address Aj are read out in step 812. , ends the process. On the other hand, this address Aj
If it is the erase data storage area 3b, the current time is compared with the erase time written in address Aj+1 in step 813, and if the current time has not passed the erase time, the contents of address A are stored in step 812. Read and end processing.

However, if the current time exceeds the erasure time in step 813, the process moves to the next step S14, making it impossible to read the contents of this address Aj, and proceeding to step 81.
At step 5, the contents of address △j are erased and the process ends.

In other words, if confidential data, etc. is stored as erase data in the erase data storage area 3b in pairs with the erase time, when the read time exceeds the erase time, the data will be made unreadable and will be erased further. ing. Therefore, even if the IC card is handed over to a third party, as long as the erasure time has passed, there is no possibility that the third party will steal the confidential data.

The processing shown in FIGS. 3 and 4 above connects the IC card 1 and the external device 2 as shown in FIG.
It is executed by the internal CPU or the control mechanism 2b in the external device 2. Further, time management can be realized by incorporating a clock function into either the IC card 1 or the external device 2.

Furthermore, when the external device 2 and the IC card 1 are connected, by comparing the erasure time corresponding to all the erased data in the erased data storage area 3b with the current time, all the erased data whose erasing time has passed can be erased. can.

Furthermore, in this embodiment, the erasing time is set in the erasing data storage area 14.
Although the write time is stored in the erase data storage area 3b, the write time may be stored in the erase data storage area 3b. In this case, by comparing the current time and the write time + storage time, it is possible to determine whether or not the erase data needs to be erased. Able to process judgments. Also, the storage time can be made variable. Furthermore, without dividing the data storage area 3 into the normal data storage area 3a and the erased data storage area 3b, information indicating whether the data is erased data is added to the data to create a data storage area lii! A method of storing the data in 3 is also conceivable.

(Effects of the Invention) As explained above, according to the present invention, by decoding identification information such as erasure time, only data that needs to be erased can be made unreadable and erased after a predetermined period of time has elapsed. Therefore, if confidential data is written in pair with discrimination information as erase data, this confidential data can be made unreadable and erased after a predetermined period of time has elapsed, so that confidentiality can be reliably protected.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of an IC card that is an embodiment of the present invention, FIG. 2 is a memory configuration diagram of a non-luminous programmable memory in the IC card shown in FIG. 1, and FIG.
FIG. 4 is a flowchart showing processing procedures for writing and reading from an IC card having the memory configuration shown in FIG. 2, respectively. In the figure, 1 is an IC card, 3 is a data storage area, and 3 is a data storage area.
A is a normal data storage area, and 3b is an erased data storage area. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) I who has at least a non-ephemeral readable/writable memory
In the C card, an IC is provided with a storage area in the memory that can store, in correspondence with the data, discrimination information that can determine whether or not the data should be erased after a predetermined period of time has elapsed from the time when the data was stored in the memory. card. (2) The IC card according to claim 1, wherein the discrimination information is a storage time of the data. (3) The IC card according to claim 1, wherein the discrimination information is a time at which the data should be erased.