JPH01181182A - Data storing system for portable electronic device - Google Patents

Abstract

PURPOSE:To significantly increase reliability against the falsification of data stored by himself by setting the change traces information corresponding to the storage data to the condition to show that the change traces are present when the storage data are changed. CONSTITUTION:When a data rewriting action request is executed from an external part, the data rewriting processing is executed for the area designated, and when the processing is completed, area definition information to define the designating area is referred to and the change traces information added to the area definition information is set to the condition in which the change traces are present. When the access request of data reading is executed, the area definition information to define the designated area is referred to, and it is checked whether or not the change traces information added to the area definition information is set to the condition in which the change traces are present. When the information is set to the condition in which the change traces are present, it is judged that the storage data in the area are changed and processing is executed based on such changes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to an integrated circuit (IC) chip having a built-in IC (integrated circuit) chip having a non-volatile memory and a control element such as a CPU.
The present invention relates to a data storage method for a portable electronic device called a C-card, which stores data in its memory.

(Prior Art) Recently, an IC card containing a built-in IC chip having a nonvolatile memory and a control element such as a CPU has been developed as a new portable data storage medium. This kind of I
The C card accesses a built-in nonvolatile memory using a built-in control element, and inputs and outputs necessary data in response to external requests.

Now, the data stored in the memory of such an IC card is generally not allowed to be output to the outside or to be changed without proper access, and access is also restricted to those who access it. Therefore, the side that performs processing using the data stored in the memory can naturally treat the data stored in the memory as reliable.

However, considering the worst case scenario (for example, if a legitimate person enters data in the wrong place even though he/she has legitimate access), especially if data is to be rewritten (including overwritten), i.e. Write protection information (flag) is added to stored data that is not desired to be changed, and the write protection information is always checked when accessing to prevent erroneous writing.

In this way, conventionally, stored data has been protected only by write protection information. However, for example, if there are multiple people in the same area who can freely manipulate the write protection information, the stored data may have been stored by the first write operation, or the data may have been overwritten on top of the data that should have been stored. Or, there was no way to know whether the data had been partially changed. For this reason,
For example, when handling data in an IC card, the reliability of the stored data against tampering is significantly reduced, and it is impossible to read and handle the data without knowing that it has been tampered with, and prevent the harm caused by this.

(Problems to be Solved by the Invention) When handling stored data as described above, the present invention is capable of handling artificial data because it is not possible to know whether the stored data is the same as the initially stored data or the data that has been changed. This was done to solve the problem of not being able to prevent the harmful effects of using falsified data due to tampering.It is possible to easily know whether the stored data is the same as the originally stored data or the data that has been changed. It is an object of the present invention to provide a data storage method for a portable electronic device that can prevent harmful effects caused by using falsified data due to data falsification.

[Structure of the Invention] (Means for Solving the Problems) A data storage system for a portable electronic device of the present invention includes a nonvolatile memory and a control unit for reading and writing data to the nonvolatile memory. and selectively performs external input/output, and the nonvolatile memory has a data area for storing data, and an area definition for storing a plurality of area definition information that defines dividing this data area into a plurality of areas. In a portable electronic device that is divided into an information area, when data is stored in the divided area, change trace information is added to at least one of the data or area definition information defining the area, The present invention is characterized in that when changing the stored data in the divided area, the change trace information is set to a state indicating that there is a change trace.

(Function) When storing data, change trace information is added to at least one of the data or the area definition information that defines the area where the data is stored, and when the stored data is changed, the stored data By setting the change trace information corresponding to the stored data to a state indicating that there is a change evidence, when the stored data is accessed, by checking the change trace information corresponding to the stored data, it is possible to determine whether the initially stored data is the same or the data has been changed. It is easy to know whether Therefore, when handling stored data, the reliability against tampering with the data stored by the user is significantly increased, and it is possible to prevent the user from reading and handling the data without knowing that it has been tampered with, and thereby preventing any harm caused by this. Furthermore, by finding changed data, there is evidence that the stored data has been accessed by another person, and safety can be reconfirmed.

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

FIG. 4 shows an IC as a portable electronic device according to the present invention.
This shows an example of the configuration of a card, including a control element (for example, a CPU) 11 as a control unit, and an erasable nonvolatile memory 1.
2, a program memory 13, and a contact section 14 for electrically communicating with an external device (not shown); 13)
is composed of one IC chip (or multiple IC chips) and is embedded within the IC card body.

The program memory 13 is composed of, for example, a mask ROM, and stores a control program for the control element 11 and the like. The memory 12 is used to store various data, and is composed of, for example, an EEFROM.

The memory 12 is roughly divided into three sides, an area definition information area 21 and a data area 22, as shown in FIG. 3, for example. The area definition information area 21 stores a plurality of pieces of area definition information that divides the data area 22 into a plurality of areas.

The area definition information that defines the division of one area consists of an area number that defines a unique number for the area, a start address that defines the position of the area in the data area 22, and an area size that defines the size of the area. . Change trace information (flag) is added to each area definition information in the area definition information area 21 to check whether there is any change evidence in the data in the area defined by the area definition information. has been done.

With this configuration, when there is an external data write request, the control element 11 writes the area definition information area 21
By referring to area definition information having information that defines a designated area within the area, the state of the designated area is recognized and a data write operation is performed. When writing data in a designated area, for example, information for checking data validity is added to the data, and the data is also called a record and treated as a unit of stored data. Note that, for example, if only one record exists in one area and a data write request is made, existing data may be overwritten. Additionally, adding data to an area means adding a new record, or rewriting data in an existing record if a record is specified.

If, for example, an external request is made to rewrite data to an IC card having area definition information to which such change trace information has been added, the rewrite operation is performed according to the flowchart shown in FIG. That is, upon receiving a command from the outside, the control element 11 determines whether the received command is a data rewrite command or not, and if it is not a data rewrite command, the control element 11 proceeds to another processing routine corresponding to the received command. As a result of the above judgment, if it is a data rewrite command, the control element 11 checks whether the command message is normal or not, and if it is abnormal, outputs the status of command message abnormality to the outside and ends the process. .

If the result of the above check is normal, the control element 11
Data rewriting processing is executed for the area specified by the command. When this data rewriting process is completed, the control element 11 sets the change trace information added to the area definition information to a state with change evidence by referring to the area definition information that defines the specified area, and Outputs the data rewriting completion status to the outside and ends the process.

Note that if there is a new data additional write operation request for the same area, the change trace information is set to a state with no change trace, since the data does not change.

Next, the operation when there is an access request such as data read to the area where data is stored as described above will be explained with reference to the flowchart shown in FIG. When an access request is made to a certain area, the control element 11 determines whether the access can be permitted or not, and if the access is not permitted, the process proceeds to access error processing. If permission is possible, the control element 11 refers to the area definition information that defines the specified area and determines whether the change trace information added to the area definition information is set to a state with change evidence. Check.

As a result of the above check, if it is not set to a state where there is evidence of modification, the control element 11 determines that the stored data in that area has not been modified and remains the initially stored data, and performs the predetermined data based on this. Processing (reading of stored data) is performed. As a result of the above check, if it is set to a state where there is evidence of modification, the control element 11 determines that the stored data in that area has been modified, and performs a predetermined process based on this (data reading is not possible or stored data is not readable). (error handling such as status output with evidence of changes)
Do this.

In this way, when storing data in an area, change trace information is added to the area definition information that defines the area, and when changing the stored data in the area, the area where the stored data is stored is By setting the change trace information added to the area definition information to be defined to a state indicating that there is a change trace, it is possible to give an EPROM reading meaning to each area. Thereby, when accessing stored data, by checking the change trace information corresponding to the stored data, it is possible to easily know whether the initially stored data is the same or the data has been changed.

Therefore, when handling data stored in an IC card, reliability against tampering with the data stored by the IC card is significantly increased, and it is possible to prevent harm caused by reading and handling the data without knowing that it is tampered data. Furthermore, by finding changed data, there is evidence that the stored data has been accessed by another person, and safety can be reconfirmed.

In the above embodiment, the case where the processing is performed in units of areas has been described, but the processing may be performed in units of records. In that case, add change trace information to each record, and when the record is specified for data rewrite operation,
By setting the change trace information added to the record to a state in which there is a change trace, the same effects as in the embodiment described above can be obtained.

[Effects of the Invention] As detailed above, according to the present invention, when handling stored data, it is possible to easily know whether the stored data is the same as the initially stored data or the data that has been changed. It is possible to provide a data storage method for a portable electronic device that can prevent harmful effects caused by using tampered data due to data tampering.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention, and FIG. 1 is a flowchart explaining a data rewriting operation, FIG. 2 is a flowchart explaining an area access operation, and FIG. 3 is a flowchart explaining an area access operation.
The figure is a block diagram schematically showing the configuration of a nonvolatile memory, and FIG. 4 is a block diagram schematically showing the configuration of an IC card.・ 11... Control element (control unit), 12...
...Nonvolatile memory, 13...Program memory, 21...Area definition information area, 22.
...Data area. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 L-+-J Figure 4 Figure 3

Claims (1)

[Scope of Claims] A non-volatile memory and a control unit for reading and writing data to the non-volatile memory,
The nonvolatile memory selectively performs external input and output, and the nonvolatile memory has a data area for storing data and an area definition information area for storing a plurality of area definition information for dividing and defining this data area into a plurality of areas. In a divided portable electronic device: When storing data in a divided area, change trace information is added to at least either the data or the area definition information that defines the area, and the divided area is A data storage method for a portable electronic device, characterized in that when changing stored data in an area, the change trace information is set to a state indicating that there is a change trace.