JP2004152056A - Ic card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IC card having a data protecting function for making it unnecessary for a host device which is likely to write erroneous data to perform any rewriting processing and a function for informing the host device that the data has been written back in performing data write-back processing. <P>SOLUTION: This IC card is provided with an arithmetic processing part 5, a volatile memory 2, a read only non-volatile memory 3 and a read/write enabling non-volatile memory 4. This system is provided with a function for writing data to be written in the other area of the second non-volatile memory 4 before writing data in the second non-volatile memory 4 and a function for recording write-back information 14 indicating that the data to the second non-volatile memory 4 has been written back in the second non-volatile memory 4. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an IC card and information processing thereof, and more particularly to data protection in a data write process to a readable and writable nonvolatile memory of the IC card.
[0002]
[Prior art]
In recent years, IC cards have been used in various fields. Each IC card includes at least a read-only nonvolatile memory and a read / write nonvolatile memory. Data writing and reading are performed on the read / write nonvolatile memory as needed. A data write processing time for writing data is required to be about 3 ms to 5 ms.
[0003]
As a special case, it is assumed that the power supplied to the IC card during the writing process is reduced or cut off. In this special case, the writing process is not completed, and the data in the read / write nonvolatile memory area to be written may be destroyed.
[0004]
In order to avoid this problem, conventionally, when the write processing has not been completed, the data indicating the data destruction of the write target area and / or the higher-level device perform the write-back process of the IC card to the higher-level device that sent the write data to the IC card. Has been notified to the host device via the interface of the IC card.
[0005]
[Problems to be solved by the invention]
In the above-mentioned conventional method, since the higher-level device at the time of failure in the write process does not always match the higher-level device to be rewritten, data used for the rewrite process by the higher-level device may be different. .
[0006]
Therefore, a technical problem of the present invention is to protect a data by performing a write-back process by an IC card so as to eliminate the need for a rewrite process by a higher-level device that may write erroneous data. It is an object of the present invention to provide an IC card having a function of notifying a higher-level device that the operation has been performed.
[0007]
[Means for Solving the Problems]
According to the present invention, in an IC card including a read-only nonvolatile memory, a readable and writable nonvolatile memory, and an interface unit for exchanging data with a higher-level device as a terminal to be communicated, the IC card received from the higher-level device. When data is written to a predetermined area of the readable and writable nonvolatile memory, data already written to a write target area of the readable and writable nonvolatile memory is written to another area of the readable and writable nonvolatile memory. And a function of storing write processing information indicating a data length and a start address of data newly written to the read / write nonvolatile memory in a memory management unit of the read / write nonvolatile memory. At the end of the newly written data, Feature data calculated from the data string and the written data indicating the end of (checksum), IC card, characterized in that it has a function of writing information written back indicating whether performed writeback is obtained.
[0008]
Further, according to the present invention, in the IC card, at the time of activation of the IC card, based on the write processing information, the area of the nonvolatile memory in which the last write operation was performed last time is verified, and after the data length, A function to verify that the writing has not been completed by verifying the data string indicating the end of the data and calculating the feature data based on the written data and comparing the calculated data with the written feature data. An IC card characterized by having the above is obtained.
[0009]
Further, according to the present invention, in the IC card, after detecting that the writing has not been completed, it is possible to write back the data previously written in another area and to perform the write back at the end of the written back data. Thus, there is provided an IC card having a function of writing the write-back information shown and notifying the host device that the previous data writing has not been completed normally.
[0010]
Further, according to the present invention, in the IC card, when a higher-level device performs processing such as reading, writing, and collation on the rewritten data, the higher-level device refers to the rewriting information, and the data is written in the rewritten data. An IC card having a function of notifying a higher-level device of a certain fact is obtained.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0012]
FIG. 1 is a block diagram showing a schematic configuration of an IC card according to an embodiment of the present invention. As shown in FIG. 1, on an IC chip 1 mounted in an IC card according to the present embodiment, an interface 6 for exchanging data with a host device 7, an arithmetic processing unit 5 for processing a control program, and a volatile A memory (RAM) 2, a read-only nonvolatile memory (ROM, first nonvolatile memory) 3 for storing a control program, and a read / write nonvolatile memory (EEPROM, second memory) for storing write or rewrite data Nonvolatile memory 4).
[0013]
In the present embodiment, the read-only memory (EEPROM) 4 which can be electrically written and erased is used as the read / write nonvolatile memory, but a ferroelectric nonvolatile memory can also be used.
[0014]
The read-only nonvolatile memory 3 stores a control program for performing a data write process, a data write incomplete detection process, and a data write-back process, but the volatile memory 2 and / or the read / write nonvolatile memory 4 Can also be stored.
[0015]
FIG. 2 is a structural diagram showing the readable / writable nonvolatile memory 4 of the IC card of FIG. The non-volatile memory 4 that can read and write data includes an area 11 for writing data, a data string 12 indicating the end of data, characteristic data (check sum) 13 of data, It has write-back information 14. Also, a memory management unit 9 for holding write processing information indicating a data length 15 and a start address 16 of data to be newly written, and writing data in the write target area 8 before writing data in the write target area 8 , An evacuation memory area 10 held in an IC card.
[0016]
Next, referring to FIG. 3 in addition to FIG. 1 and FIG. 2, the data write processing, the data write incomplete detection processing, and the data write back processing for the IC card will be described. In the present embodiment, a write command is used as a data string to be subjected to write processing, and a read command is used as a data string to not be subjected to write processing.
[0017]
1) When a power supply voltage is supplied from the host device 7 and an initial response operation is requested (S1 in FIG. 3), the IC card makes an initial response to the host device (S2 in FIG. 3) and then stays in a reception waiting state. . At this time, it is assumed that the data string 12 indicating the end of the data indicates a normal data string, the data characteristic data (checksum) 13 indicates a normal checksum, and the data write-back information 14 indicates no write-back.
[0018]
2) When reading is performed from the write target area 8 by a read command (S3 in FIG. 3), the IC card refers to the data write-back information 14 and detects that the data has not been written back. Is notified of the command processing result (S5 in FIG. 3).
[0019]
3) When writing is performed in the write target area 8 by a write command (S6 in FIG. 3), the IC card writes the data written in the write target area 8 to the evacuation memory area 10 and then newly writes. The data length 15 and the start address 16 of the data are written into the memory management unit 9, then the data (A) is written into the write target area 8, and the data is calculated from the data string 12 indicating the end of the data and the data (A) The written characteristic data (checksum) 13 and the data write-back information 14 are written (S7 in FIG. 3).
[0020]
4) When a power supply voltage drop occurs during the writing process (S8 in FIG. 3), the writing process is not completed (S9 in FIG. 3), the data string 12 indicating the end of the data, and the characteristic data of the data (the checksum). 13 both indicate abnormalities.
[0021]
5) When the power supply voltage is resupplied from the host device 7 and the initial response operation is requested (S10 in FIG. 3), the IC card reads the write processing information 2 start address 16 and the write processing information With reference to the one data length 15, the write target area 8 where the last write was performed last time is verified. The verification of the data string 12 indicating the end of data and the calculation of characteristic data based on the written data and comparison with the written characteristic data (check sum) 13 indicate that the writing has not been completed normally. Is detected (S11 in FIG. 3). After that, the IC card writes the data written in the save memory area 10 back to the write target area 8 and changes the data write-back information 14 to “write-back”. After receiving an initial response (S13 in FIG. 3) indicating that the processing has not been completed normally, the apparatus remains in the reception waiting state.
[0022]
6) When reading is again performed on the write target area 8 by the read command (S14 in FIG. 3), the IC card refers to the data write-back information 14 and detects that the data has been written back ( In step S15 in FIG. 3, the host device is notified of the result of the command processing and that the data is rewritten data (S17 in FIG. 3).
[0023]
7) When writing to the write target area 8 again by the write command (S18 in FIG. 3), the IC card writes the data written in the write target area 8 to the evacuation memory area 10 and then writes the data. Data (A) is written into the target area 8, and at the end of the data, a data string 12 indicating the end of the data, feature data (check sum) 13 calculated from the data (A), and data write-back information 14 are written (FIG. 3). S19), and notifies the host device of the command processing result (S20 in FIG. 3).
[0024]
8) When reading is again performed on the write target area 8 by the read command (S21 in FIG. 3), the IC card refers to the data write-back information 14 and detects that the data has not been written back. The command processing result is notified to the host device (S23 in FIG. 3).
[0025]
It goes without saying that various modifications are possible as described below.
[0026]
For example, by verifying the data string 12 indicating the end of the data, calculating the characteristic data based on the written data, and comparing the calculated characteristic data with the written characteristic data (check sum) 13, the writing is completed normally. The function of detecting the absence can be realized by a software program. Of course, the IC card has a function of notifying that writing has not been completed normally when writing is not completed, but this function may be realized by a software program.
[0027]
The data length to be written to the write target area 8 can be up to the same data length as the save memory area 10, and the length can be set arbitrarily.
[0028]
Further, a plurality of write target areas may exist. In this case, one memory management unit 9 having the same number of write target areas 8 and one evacuation memory area 10 having the same data length as the maximum write target area 8 are required. is there.
[0029]
【The invention's effect】
As described above, according to the present invention, since the IC card itself writes back the uncompleted data area, data protection that does not require rewriting processing by a higher-level device that may write erroneous data is not required. An IC card having a function can be provided.
[0030]
Further, it is possible to provide an IC card having a function of notifying a host device that data has been written back when data write-back processing is performed due to a drop in power supply voltage.
[0031]
Furthermore, by adding a data string indicating the end of data and characteristic data (check sum) of data to data to be written to the readable and writable nonvolatile memory, even when a data write failure of at least one bit occurs, This effect is obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram of an IC card according to an embodiment of the present invention.
FIG. 2 is a structural diagram of a readable / writable nonvolatile memory in the IC card of FIG. 1;
FIG. 3 is a flowchart showing a data protection process in the IC card of FIG. 1;
[Explanation of symbols]
1 IC chip 2 Volatile memory (RAM)
3 Read-only nonvolatile memory (ROM)
4. Read / write nonvolatile memory (EEPROM)
5 arithmetic processing unit 6 interface 7 host device 8 write target area 9 memory management unit 10 evacuation memory area 11 area to write data 12 data sequence 13 indicating end of data data characteristic data (checksum)
14 Data write-back information 15 Data length 16 Start address

Claims (4)

In an IC card including a read-only nonvolatile memory, a readable / writable nonvolatile memory, and an interface unit for exchanging data with a host device as a communication target, data received from the host device can be read / written. A function of writing data already written in a write target area of the readable and writable nonvolatile memory to another area of the readable and writable nonvolatile memory when writing to a predetermined area of the nonvolatile memory; The function of storing the data length of data newly written to the readable and writable nonvolatile memory and the write processing information indicating the start address in the memory management unit of the readable and writable nonvolatile memory; Finally, data indicating end of data Data string and written feature data (checksum) calculated from the data, IC card and having a function of writing the write back information indicating whether performed writeback. 2. The IC card according to claim 1, wherein at the time of activation of the IC card, based on the write processing information, an area of the non-volatile memory in which data has been written last is verified. It has a function of detecting that the writing has not been completed by verifying the data string indicating the end, calculating the feature data based on the written data, and comparing the calculated feature data with the written feature data. Characteristic IC card. 3. The IC card according to claim 1, wherein after detecting that the writing has not been completed, the data previously written in another area is rewritten, and the rewriting is performed at the end of the rewritten data. An IC card having a function of writing write-back information and notifying a higher-level device that previous data writing has not been completed normally. 4. The IC card according to claim 1, wherein when the host device performs processing such as reading, writing, and collation on the rewritten data, the data is rewritten by referring to the rewriting information. An IC card having a function of notifying a host device of data.

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