JP2005128817A - Information storage device and information processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information storage device for enabling the exclusion of a nonvolatile storage element wherein a service life expires from a system to secure security performance of the system, and to provide an information processing system using the information storage device as a storage device constituting the system. <P>SOLUTION: This information storage device has a means for inputting and outputting information from an external device having a data processing function, and the nonvolatile memory element wherein a use service life remains. The information storage device decides the service life of the nonvolatile memory element by comparison of a count result obtained by counting the number of update times updated according to processing operation of the information storage device, stored in the nonvolatile memory element, and a preset service life prediction value, and does not perform the processing operation of the information storage device itself by returning rejection notification to a processing request from the external device when a result of the decision reaches the service life prediction value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an information storage device including some nonvolatile storage medium as a data storage device, and an information processing system using the information storage device as a storage device constituting the system.

  In recent years, in addition to magnetic storage devices and optical storage devices, nonvolatile semiconductor storage devices using semiconductor storage elements such as EEPROMs and flash memories have become common. As an application example of such a semiconductor storage device, an IC card, which is a storage medium with high security performance for storing valuable value information secretly, has been put into practical use. However, in recent years, wireless communication is not used as a communication I / F. Contact-type IC cards are expanding their applications due to their convenience in handling. Furthermore, a storage medium using a wireless communication I / F called an RFID or an IC tag, which does not require security performance as much as an IC card, is becoming common.

  A storage device such as an EEPROM or a flash memory has a limitation that the number of updates is limited because the storage element deteriorates as the storage content is updated, and the service life of the storage device is limited. A number of techniques for extending the lifetime have been proposed, and there is a storage device using a flash memory disclosed in Patent Document 1 as one of the techniques for avoiding problems when the lifetime is reached. The flash file system according to the related art performs a function of determining deterioration of a flash memory device included in the flash file system and reports an error due to deterioration of the memory device to a host system communicating with the flash file system. It has a function. In addition, the host system according to the prior art has a function of notifying the user of the host system of the occurrence of the error in response to an error report issued by the flash file system. With the above configuration, the user of the flash file system can know the occurrence of an error due to the deterioration of the memory element on the flash file system.

JP-A-6-124596

  According to the above-described conventional flash file system, a user of the flash file system can know that an error has occurred due to deterioration of a memory element on the flash file system. However, although this conventional technique is effective in preventing data errors in general information storage devices, for example, mutual device authentication and communication paths between the host system and the storage device realized by an IC card or the like are used. In the information storage device having a security function, such as data encryption, the prevention of data error that is a threat to the entire system, the elimination of the information storage device with deteriorated function, etc. are not fully disclosed.

  Accordingly, the problem of the present invention is that the deterioration of the nonvolatile storage element included in the information storage device is regarded as a threat to system security, and the information storage device including the nonvolatile storage element that has reached the end of its life is excluded from the system. Another object of the present invention is to provide an information storage device capable of ensuring the security performance of the system, and an information processing system using the information storage device as a storage device constituting the system.

In order to solve the above problems, the present invention provides:
A non-volatile storage device using a memory element having a service life,
There is provided a storage device characterized by counting the number of updates of the storage device area to determine the lifetime and invalidating its function at the end of the lifetime.

  As described above, according to the present invention, an information storage device that does not cause a decrease in security function during the lifetime of the information storage device that constitutes the information processing system according to the present embodiment, and an information storage medium with a decreased security function It is possible to provide an information processing system capable of safely transferring valid user data to a new information storage device.

  Embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS. 1 to 7 and FIGS. 9 to 12. FIG. First, a schematic configuration of an information processing system according to the present embodiment, an information processing apparatus that constitutes the information system, and an information storage apparatus will be described with reference to FIG.

  FIG. 1 is a schematic configuration diagram of an information processing system according to the present embodiment.

In the figure, reference numeral 101 denotes an information processing apparatus (hereinafter referred to as a host) including a computing unit that processes some data, such as a PC, a portable terminal, and a cellular phone.
Reference numeral 102 denotes an information storage device including at least an information storage area including a nonvolatile memory having a lifetime due to deterioration of a memory element such as an EEPROM or a flash memory (hereinafter referred to as a storage device).

  Reference numeral 103 denotes a non-volatile memory that is provided by the storage device 102 and has a lifetime due to deterioration of a memory element such as an EEPROM or a flash memory.

  Reference numeral 104 denotes a communication path between the host 101 and the storage device 102.

  Reference numeral 105 denotes an interface device (hereinafter, referred to as an I / F) provided by the storage device 102 for the storage device 102 to communicate with the host 101. The type of the I / F 105 is arbitrary. For example, a method of exchanging data by addressing from the host 101 and enabling / disabling of a control signal through a wired bus connection may be adopted, or the host 101 may be connected by a wireless serial connection. The storage device 102 may return a response response to the command request output by

  Reference numeral 106 reads a value in a certain area on the nonvolatile memory 103 provided by the storage device 102, performs a predetermined operation such as adding 1 to the value, and converts the obtained value into the nonvolatile memory 106. This is an addition function for writing to the original area on the memory 103.

  107 reads out the value of a certain area on the non-volatile memory 103 provided by the storage device 102, and performs a predetermined operation such as size determination and match determination between the value and another value to obtain the value. This is a comparison function that determines the branch of another predetermined function based on the result obtained.

  Reference numeral 108 denotes an encryption function that is provided by the storage device 102 and performs encryption / decryption processing on separately input data using an encryption key held on the nonvolatile memory 103. The encryption algorithm used by the encryption function is arbitrary.

  Reference numeral 109 denotes password information which is held in a predetermined area on the nonvolatile memory 103 and whose value is updated as necessary by communication with the host 101. The password 109 is information used for the purpose of preventing unauthorized access when exchanging certain data between the host 101 and the storage device 102, for example, when reading data from the storage device 102. Further, a plurality of passwords 109 may be stored on the nonvolatile memory 103 as necessary.

  Reference numeral 110 denotes a random number value that is held in a predetermined area on the nonvolatile memory 103 and whose value is updated as necessary by communication with the host 101. The random value 110 is used as a challenge value used when exchanging certain data between the host 101 and the storage device 102, for example, when performing device authentication of the host 101 by the challenge and response method of the host 101. As a random number generation method, for example, pseudo random number generation using the encryption function 108 in the OFB (Output Feedback) mode, or pseudo random number generation using a hash function function, which is not shown in FIG. 1, may be used. The holding area of the random number value 110 on the nonvolatile memory 103 is updated every time a random number needs to be generated. Further, a plurality of random number values 110 may be stored on the nonvolatile memory 103 as necessary. As a pseudo-random number generation method using the encryption function 108 in the OFB mode, first, a value is randomly given to the storage device 102, and the value is used as an IV (initial vector). Using the encryption function 108, the ciphertext obtained by encrypting the IV with a predetermined encryption key is used as a random value, and the ciphertext is stored in the nonvolatile memory 103 as the random value 110. Next, when a random number becomes necessary, the random number value 110 is encrypted with a predetermined encryption key using the encryption function 108 and used in the same manner.

  Reference numeral 111 denotes an encryption key that is held in a predetermined area on the nonvolatile memory 103 and is read and used by the encryption function 108. If the public key encryption algorithm is used, the secret key and the public key of the storage device 102 are secretly held on the nonvolatile memory 103 as the encryption key 111. If the common key encryption algorithm is used, the key shared with the host 101 is kept secretly on the nonvolatile memory 103. The encryption key sharing method is arbitrary, and the method is not limited. Further, a plurality of encryption keys 111 may be stored on the nonvolatile memory 103 as necessary.

  Reference numeral 112 denotes a count value which is held in a predetermined area on the nonvolatile memory 103 and whose value is updated as necessary by communication with the host 101. The count value 112 is updated, for example, by adding 1 each time data in a specific area on the nonvolatile memory 103 is updated. As a result, the numerical value indicated by the count value 112 indicates the number of updates of a specific area on the nonvolatile memory 103. A plurality of count values 112 may be stored on the non-volatile memory 103 in accordance with the number of specific areas on the non-volatile memory 103 for tracking the number of updates.

  Reference numeral 113 denotes a lifetime number value held in a predetermined area on the nonvolatile memory 103. The lifetime number value 113 is the number of updates of the memory element that can guarantee normal operation in the nonvolatile memory 103 provided in the storage device 102. The comparison function 107 can determine whether or not a specific area on the nonvolatile memory 103 has reached the end of life by comparing the count value 112 with the life count 113.

  Reference numeral 114 denotes an operation mode value that defines what kind of response response is returned in response to an operation request command input from the host 101 to the storage device 102, which is held in a predetermined area on the nonvolatile memory 103. is there. Here, it is assumed that the following four types of operation modes are provided. The operation mode 00 is an initial setting mode and cannot be used normally. The operation mode 01 is a normal use mode. The operation mode 02 is a warning mode, and can be normally used, but is notified that the storage device 102 is near the end of its life. The operation mode 03 is a limited operation mode and cannot be normally used, and only a specific operation that is separately defined is performed. The operation mode is not necessarily limited to this, and a more detailed operation mode may be set or a smaller number of operation modes may be used.

Note that it is not always necessary to provide / store all the functions of the storage device 102 and the storage information of the nonvolatile memory 103 described above. The storage device 102 includes at least a nonvolatile memory 103 and an I / F 105, and may include an addition function 106, a comparison function 107, and an encryption function 108 as necessary. The nonvolatile memory 103 may store a password 109, a random number value 110, an encryption key 111, a count value 112, a lifetime number 113, and an operation mode 114 as necessary.
Further, although the life count value 113 is held in the nonvolatile memory 103, the holding carrier is not necessarily limited to the nonvolatile memory 103 as long as it is held in the storage device 102. Although not shown in FIG. 1, as another retention method of the lifetime count value 113, a mask ROM having a lifetime due to deterioration of a memory element, which is different from the nonvolatile memory 103, or a constant output is stored in the storage device 102. A logic circuit may be provided, and the life count value 113 may be held in the mask ROM or constant output logic circuit.

  Although not shown in FIG. 1, the nonvolatile memory 103 included in the storage device 102 may be provided with an area for storing some user data.

  The center of the operation of the information processing system according to the present embodiment is that the host 101 writes some data to the storage device 102 and reads the written data from the storage device 102, and each operation is performed illegally. It is to ensure that nothing happens. Next, these operations will be described with reference to the drawings.

  The outline of the device authentication operation of the host 101 by the information storage device 102 in the information processing system according to the present embodiment will be described with reference to FIGS.

  FIG. 2 is an operation conceptual diagram of commands and responses exchanged between the host 101 and the storage device 102 when writing to the storage device 102 in the information processing system according to the present embodiment. The host 101 transmits an authentication request command to the storage device 102 (201).

  In response to this, the storage device 102 returns one of the following three types of responses. A challenge value is returned in the normal use mode (202), a challenge value and a warning notification are returned in the warning mode (203), and an authentication rejection notification is returned in the limited operation mode (204).

  If the response from the storage device 102 is the challenge value 202, or the challenge value or warning notification 203, the host 101 sends a response value for the received challenge value (205).

  On the other hand, if the storage device 102 determines that the received response value is valid, it returns an authentication success notification (206), and if it determines that the response value is invalid, it returns an authentication failure notification ( 207).

  When the above-described exchange of 201, 202 (or 203), 205, 206 is completed normally, the host 101 is authenticated by the information storage device 102. In the above communication protocol, the challenge values appearing in 202 and 203 require a random value generated by the storage device 102. As described with reference to FIG. Needs to be implemented successfully. If the random value 110 cannot be updated due to the lifetime of the memory elements constituting the nonvolatile memory 103 included in the information storage device 102, the challenge value output by the information storage device 102 becomes a fixed value. As a result, by simply eavesdropping on the communication path 104, a challenge and a response value necessary for authenticating the host 101 can be obtained without knowing information secretly shared between the host 101 and the storage device 102. Can be a major threat to system security. In order to avoid such a threat, a method for normally performing the normal update of the random number will be described with reference to FIG.

  FIG. 3 is a schematic flowchart during the authentication operation of the storage device 102 according to the present embodiment. The storage device 102 examines whether or not the command input from the host 101 is an authentication request (301).

  If the command input from the host 101 is an authentication request, the storage device 102 reads the operation mode 114 stored in the nonvolatile memory 103 and determines whether the operation mode is 03 (302). If the operation mode is not 03, it is determined whether the operation mode is 02 (303). When the operation mode is not 02, 1 is added to the count value 112 stored in the nonvolatile memory 103 by using the addition function 106 (304), and the random value stored in the nonvolatile memory 103 is further added to the encryption function 108. And update (305). Next, the lifetime number 113 stored in the nonvolatile memory 103 is read and compared with the updated count value using the comparison function 107 (306). When the count value 112 is smaller than the lifetime number 113, a challenge value is transmitted (308), and the process is terminated.

  If the count value 112 is greater than the life count 113 as a result of the comparison in 306, the operation mode 114 stored in the nonvolatile memory 103 is updated to the operation mode 02 (307). Further, a challenge value and a warning notification are transmitted (312), and the process is terminated.

  If the operation mode is 02 as a result of the comparison, the random number value stored in the nonvolatile memory 103 is updated using the encryption function 108 (309). Next, the random number value to be written is compared with the random number value stored in the nonvolatile memory 103 using the comparison function 107, and it is determined whether or not the update is successful (310). If the random number update 310 is successful, a challenge value and a warning notification are transmitted (312), and the process ends. When the random number update 310 fails, the operation mode 114 stored in the nonvolatile memory 103 is updated to the operation mode 03 (311). Further, an authentication rejection notification is transmitted (313), and the process is terminated.

  If the operation mode is 03 as a result of the comparison 302, an authentication rejection notification is transmitted (313), and the process is terminated.

  Next, an outline of an operation of reading user data stored in the information storage device 102 by the host 101 in the information processing system according to the present embodiment will be described with reference to FIGS. 4 and 5.

  FIG. 4 is an operation conceptual diagram of commands and responses exchanged between the host 101 and the storage device 102 when data is read from the storage device 102 in the information processing system according to the present embodiment. The host 101 transmits a read request command and a read password shared in advance to the storage device 102 (401).

  In response to this, the storage device 102 returns one of the following three types of responses. In the normal use mode, the read data and the password to be used for the next reading are returned (402), in the warning mode, the read data, the password to be used in the next reading and the warning notification are returned (403), and in the limited operation mode, the read rejection notification is returned ( 404).

  When the above-described exchange of 401, 402 (or 403) has been completed normally, the host 101 has succeeded in reading data from the information storage device 102. In the above communication protocol, a password that appears in 402 and 403 requires a random value generated by the storage device 102. A system security threat is generated with the same logic as described in FIG. In order to avoid this threat, a method for normally performing the normal update of the random number will be described with reference to FIG.

  FIG. 5 is a schematic flowchart at the time of data reading operation of the storage device 102 according to the present embodiment. The storage device 102 examines whether or not the command input from the host 101 is a read request (501).

  When the command input from the host 101 is a read request, the storage device 102 reads the operation mode 114 stored in the nonvolatile memory 103 and determines whether the operation mode is 03 (502). If the operation mode is not 03, the password 109 stored in the nonvolatile memory 103 is read and compared with the password input using the comparison function 107 (503). If the passwords match, it is determined whether or not the operation mode is 02 (504). When the operation mode is not 02, the count value 112 stored in the nonvolatile memory 103 is incremented by 1 using the addition function 106 (505), and the password 109 stored in the nonvolatile memory 103 is further changed to the encryption function 108. And update (506). Next, the lifetime number 113 stored in the nonvolatile memory 103 is read and compared with the updated count value using the comparison function 107 (507). When the count value 112 is smaller than the lifetime number 113, the read data and the updated password are transmitted (509), and the process is terminated.

  If the count value 112 is greater than the life count 113 as a result of the comparison 507, the operation mode 114 stored in the nonvolatile memory 103 is updated to the operation mode 02 (508). Further, the read data, the updated password, and the warning notification are transmitted (513), and the process is terminated.

  If the operation mode is 02 as a result of the comparison 504, the password stored in the nonvolatile memory 103 is updated using the encryption function 108 (510). Next, the password to be written is compared with the password stored in the nonvolatile memory 103 using the comparison function 107, and it is determined whether or not the update is successful (511). When the password update 511 is successful, the read data, the updated password, and a warning notification are transmitted (513), and the process ends. When the password update 511 fails, the operation mode 114 stored in the nonvolatile memory 103 is updated to the operation mode 03 (512). Further, a read rejection notice is transmitted (514), and the process is terminated.

  If the passwords do not match as a result of the comparison 503, and if the operation mode is 03 as a result of the comparison 502, a read rejection notice is transmitted (514), and the process is terminated.

  Next, an outline of an operation of writing user data to the information storage device 102 by the host 101 in the information processing system according to the present embodiment will be described with reference to FIGS. 6 and 7.

  FIG. 6 is an operation conceptual diagram of commands and responses exchanged between the host 101 and the storage device 102 when writing data to the storage device 102 in the information processing system according to the present embodiment. The host 101 transmits a read request command and a read password shared in advance to the storage device 102 (601).

  In response to this, the storage device 102 returns one of the following three types of responses. In the normal use mode, a write completion notification and a password to be used at the next writing are returned (602), in a warning mode, a write completion notification is returned, a password to be used in the next writing and a warning notification are returned (603), and in a limited operation mode, a write rejection notification is issued. Return (604).

  When the above-described exchange of 601 and 602 (or 603) has been completed normally, the host 101 has successfully written data to the information storage device 102. In the above communication protocol, passwords appearing at 602 and 603 require random values generated by the storage device 102. A system security threat is generated with the same logic as described in FIG. In order to avoid this threat, a method for normally performing the normal update of the random number will be described with reference to FIG.

  FIG. 7 is a schematic flowchart at the time of data writing operation to the storage device 102 according to the present embodiment. The storage device 102 examines whether the command input from the host 101 is a write request (701).

  If the command input from the host 101 is a write request, the storage device 102 reads the operation mode 114 stored in the nonvolatile memory 103 and determines whether the operation mode is 03 (702). If the operation mode is not 03, the password 109 stored in the nonvolatile memory 103 is read and compared with the password input using the comparison function 107 (703). If the passwords match, it is determined whether or not the operation mode is 02 (704). If the operation mode is not 02, the count value 112 stored in the nonvolatile memory 103 is incremented by 1 using the addition function 106 (705), and the password 109 stored in the nonvolatile memory 103 is further changed to the encryption function 108. And update (706). Next, the lifetime number 113 stored in the nonvolatile memory 103 is read out and compared with the updated count value using the comparison function 107 (707). When the count value 112 is smaller than the life count 113, a write completion notice and an updated password are transmitted (709), and the process is terminated.

  If the count value 112 is greater than the lifetime number 113 as a result of the comparison 507, the operation mode 114 stored in the nonvolatile memory 103 is updated to the operation mode 02 (708). Further, a write completion notification, an updated password, and a warning notification are transmitted (713), and the process is terminated.

  If the operation mode is 02 as a result of the comparison 704, the password stored in the nonvolatile memory 103 is updated using the encryption function 108 (710). Next, the password to be written is compared with the password stored in the non-volatile memory 103 using the comparison function 107, and it is determined whether or not the update is successful (711). If the password update 511 is successful, a write completion notification, an updated password, and a warning notification are transmitted (713), and the process ends. If the password update 511 fails, the operation mode 114 stored in the nonvolatile memory 103 is updated to the operation mode 03 (712). Further, a read rejection notice is transmitted (714), and the process is terminated.

  If the passwords do not match as a result of the comparison 703, and if the operation mode is 03 as a result of the comparison 702, a read rejection notice is transmitted (714), and the process is terminated.

  As described above, the storage device 102 performs only the processing requested by the host 101 in the operation mode 01 when the update count of the random number storage area of the nonvolatile memory 103 is not problematic compared to the lifetime of the memory element. . Next, when the number of updates of the random number storage area of the nonvolatile memory 103 has reached the expected lifetime of the memory element, that is, in the operation mode 02, the processing requested from the host 101 is performed and the lifetime is increased. A warning notification indicating that it is near is performed. Finally, after detecting the update failure of the random number storage area of the nonvolatile memory 103, that is, in the operation mode 03, the processing requested from the host 101 is rejected.

  The application of the lifetime control method of the memory area is not limited to the above three types of processing protocols. For example, data reading / writing may be encrypted communication using a session key instead of a password. In this case, the session key storage area is the application destination of this method. Moreover, both the observation of the number of updates of the memory area and the observation of whether the memory area has been updated may be combined, or only one of them may be applied.

  In addition, FIG. 3 shows a schematic flowchart at the time of the authentication operation of the storage device 102 according to the present embodiment. In FIG. 3, the operation mode register is referred to every time a command is input from the host 101, and authentication is rejected. It was determined whether or not to do (302). On the other hand, the separation between the operation mode 03 and the other determinations, and the operation at the time of the operation mode 03 determination may be processing by the configuration and processing flow shown in FIGS.

  FIG. 9 is another schematic configuration diagram of the information processing system according to the present embodiment. In the figure, reference numerals 102, 103, 105, and 114 are the same as those shown in FIG. Reference numeral 901 denotes an operation mode register for holding read data of a specific area of the nonvolatile memory 103. Reference numeral 902 denotes a memory I / F that writes data to the nonvolatile memory 103 and reads data from the nonvolatile memory 102. The memory I / F 902 has a function of operating according to an instruction of a power-on reset operation sequencer described later. 903 instructs the memory I / F 902 to read data from a specific area of the nonvolatile memory 103 and set the read data to the operation mode register 901 when power supply is started to the storage device 102 and a power-on reset is involved. This is a power-on reset operation sequencer. Reference numeral 904 denotes a data mask function for selecting whether to output the output data from the I / F 105 as a through output or a mask output by using the output signal of the operation mode register 901 as a selection input. Reference numeral 905 denotes processing functions of the storage device 102 such as the addition function 106, the comparison function 107, and the encryption function 108 shown in FIG.

  FIG. 10 is another schematic flowchart at the time of the authentication operation of the storage device 102 according to the present embodiment. The storage device 102 is initialized with a power-on reset at the start of power supply (1001). At power-on reset, the memory I / F 902 reads the operation mode data 114 held in the nonvolatile memory 103 by the operation of the power-on reset operation sequencer 903, and sets the operation mode data in the operation mode register 901 (1002). The output signal of the operation mode register 901 is a selection input of the data mask 904. If the operation mode data set in the operation mode register 901 is 03, the input signal from the I / F 105 is masked by the data mask 904. No valid data is input to the processing function 905 (1003, 1005). On the other hand, if the operation mode data set in the operation mode register 901 is other than 03, the input signal from the I / F 105 is input to the processing function 905 as it is (1003, 1004).

  With the above function, the storage device 102 determines its own operation mode when the power is turned on. In the operation mode 03, the input signal from the I / F 105 to the processing function 905 is blocked by the data mask 904. Functions that do not operate in mode 03 are realized.

  FIG. 11 is another schematic configuration diagram of the information processing system according to the present embodiment. In the figure, reference numerals 102, 103, 105, 114, 901, 902, 903, and 905 are the same as those shown in FIG. A reset generation function 1101 selectively outputs a reset state signal to the processing function 905 using the output signal of the operation mode register 901 as a selection input.

  FIG. 12 is another schematic flowchart at the time of the authentication operation of the storage device 102 according to the present embodiment. In the figure, reference numerals 1001, 1002, and 1003 are the same as those shown in FIG.

  The output signal of the operation mode register 901 is a selection input of the reset generation function 1001. If the operation mode data set in the operation mode register 901 is 03, the reset generation function 1101 outputs a reset state signal, and processing The function 905 is always in a reset state and does not process data (1003, 1202). On the other hand, if the operation mode data set in the operation mode register 901 is other than 03, the processing function 905 functions (1003, 1201).

  With the above functions, the storage device 102 determines its own operation mode when the power is turned on, and in the case of the operation mode 03, the processing function 905 always remains in the reset state, thereby realizing a function that does not operate in the operation mode 03. Is done.

  As described above, by using the configuration and the processing flow shown in FIG. 9 to FIG. 12, after detecting the update failure of the random value storage area of the nonvolatile memory 103, that is, in the operation mode 03, the storage device 102 is powered and operated. It is possible to realize a function of rejecting the processing requested from the host 101 by invalidating the operation on the input signal by itself at the time of start. By applying the same method, the input from the outside of the device is invalidated, so that it is possible to realize a storage device with stronger security performance that does not give even the clue of analysis for unauthorized access.

  This method is suitable for applications where it is difficult to mount a large-capacity nonvolatile memory such as an IC card or RFID, and it is difficult to put a large logic on the lifetime control of the nonvolatile memory. By managing the memory life only in the memory area important for system security, it is possible to reduce the overhead by adding a security function and achieve both sufficient security strength.

  As described above, according to the first embodiment of the present invention, in the information processing system according to the present embodiment, the lifetime of the memory element in the storage area of data important for security stored in the information storage device is determined, and the security of the system is determined. The problem that is a problem, that is, the normal operation of the data storage area where the stored data needs to be reliably updated is ensured, and the storage device in which the problem has occurred can be reliably excluded from the information processing system when the problem occurs. An information storage device can be provided.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIGS. 8 and 13 to 15. First, the schematic configuration of the information communication system according to the present embodiment, the information processing apparatus constituting the communication system, and the information storage medium will be described with reference to FIG. In the figure, reference numerals 101 to 104 and 114 are the same as those shown in FIG. 1301 is user data stored locally in the storage device 102. An independent device having the same function is indicated by adding subscripts a and b after the number 102. Here, reference numerals 102a and 102b denote independent storage devices. The same applies to the subsequent numbers. That is, FIG. 13 shows a state where a plurality of storage devices 102 a and 102 b are connected to the host 101. The storage device 102a shows the operation mode 02 shown in the first embodiment, and the storage device 102b shows the operation mode 00. That is, the storage device 102a can be used normally, but the storage device 102a is near the end of its life, and the storage device 102b is in a state where normal use is not possible while waiting for initialization.

  In the information communication system according to the present embodiment, the main operation is to move the user data 1301a stored in the storage device 102a to the storage device 102b without allowing unauthorized duplication or falsification.

Next, an outline of the operation of the information communication system according to the present embodiment will be described with reference to FIG. FIG. 14 is a schematic operation flowchart of the host 101 according to the information communication system according to the present embodiment. The host 101 requests the storage device 102a to read user data, and the storage device 102a outputs data according to the operation flow shown in FIG. As a result, the host 101 reads user data from the storage device 102a (1401). The host 101 requests the storage device 102b to write user data, and the storage device 102b generally stores the data according to the operation flow shown in FIG. As a result, the host 101 writes user data to the storage device 102b (1402). Next, the host 101 transmits an update request for changing the operation mode to 03 to the storage device 102a (1403). On the other hand, the storage device 102a roughly updates the operation mode according to the operation flow shown in FIG. 15, and notifies the host 101 of the completion of the update. (1404).
If the completion notification reception 1404 is successful, the host 101 transmits an update request for changing the operation mode to 01 to the storage device 102b (1405). On the other hand, the storage device 102b roughly updates the operation mode according to the operation flow shown in FIG. 15, and notifies the host 101 of the completion of the update. (1406).

  If both the completion notification reception 1404 and the completion notification reception 1406 are successful, the host 101 determines that the migration of the user data from the storage device 102a to 102b was successful (1407). If either the completion notification reception 1404 or the completion notification reception 1406 fails, the host 101 determines that the migration of the user data from the storage device 102a to the storage device 102b has failed (1408).

  Next, the operation of the storage device 102 when an operation mode update request is input from the host 101 will be described with reference to FIG. FIG. 15 is a schematic flowchart at the time of the operation mode update operation of the storage device 102 according to the present embodiment. The storage device 102 examines whether or not the command input from the host 101 is an operation mode update request (1501).

When the command input from the host 101 is the operation mode update, the storage device 102 reads the operation mode 114 stored in the nonvolatile memory 103 and determines whether the operation mode is 00 to 03 (1502 to 1504). ). It is determined whether the requested operation mode value after update is a valid numerical value (operation mode 00 to 003) and larger than the current operation mode (1505, 1508, 1509). When the operation mode value is updated to a valid and large value, the operation mode is updated (1506), and an update completion notification is transmitted to the host 101 (1507). If the updated operation mode value is invalid or is updated to a value smaller than or equal to the current operation mode, an update rejection notification is transmitted to the host 101 (1510).

  According to the procedure 1403, the operation mode of the storage device 102a having a short lifetime is updated from mode 02 to mode 03, and the storage device 102a transitions to a state in which normal operation cannot be performed. After confirming the normal completion of the procedure 1403 by the procedure 1404, the mode of the storage device 102b waiting for the initial setting is updated from the mode 00 to the mode 01 by the procedure 1405, and the storage device 102b is operated normally. Transition to a possible state.

  The above procedure guarantees the migration of user data from the storage device 102a that is guaranteed to have no functional deterioration to the storage device 102b that has not yet been used, and the user data in the storage device 102b Prior to being validated, invalidation of the storage device 102a is guaranteed. As a result, it is possible to guarantee that the user data stored in the storage device 102 with enhanced security functions by device authentication, data encryption, etc. is the only valid data. When greeted, user data can definitely be transferred to another storage device. Further, when the operation mode of the storage device 102a is 03, the host 101 can exclude the storage device having a deteriorated security function from the system by refusing data transfer from the storage device 102a.

  It should be noted that two numerical values may be stored: the number of lifetimes that can be guaranteed in the storage area 113 of the non-volatile memory 103, and the number of times that is less than the number of times determined by the number of times (hereinafter referred to as the marginal lifetime). . For example, in the case of device authentication of the host 101, the comparison is made by referring to the number of remaining lifetimes in the comparison 306, and the comparison is made by referring to the number of lifetimes rather than the successful update of the random value in the comparison 310. Thereby, it becomes possible to add the remaining number that can be authenticated up to the actual number of lifetimes to the warning notification. FIG. 8 is an example of a command / response combination in the authentication communication protocol between the host 101 and the storage device 102 to which the present method is applied. In the response communication frame, in addition to the challenge transmission notification code with warning, the remaining authenticable number is also transmitted. The same control is possible in the data read operation and data write operation.

  This makes it possible to notify the host 101 of the number of accesses until the storage device 102 becomes invalid, and the effect of increasing the choices of methods to be handled as a system can be obtained.

  For example, assuming application to a so-called immobilizer system in which the host 101 is an automobile and the storage device 102 is a key of the automobile, there is an effect of reducing the risk of illegally starting the automobile due to a security error due to deterioration of the storage device 102. As a result, warning of the life of the key in advance makes it possible to avoid operational problems such that the key suddenly becomes invalid and the vehicle cannot be started.

  Also, assuming application to a payment system in which the host 101 is a payment device, the storage device 202 is user data, and some payment information, value information, etc. are stored in the nonvolatile memory 103, or an electronic wallet. Similarly, it reduces the risk of fraudulent manipulation of monetary information due to a security error, and can also avoid operational problems such as suddenly becoming unable to use an electronic wallet by warning the key lifetime in advance. It becomes.

  As described above, according to the second embodiment of the present invention, an information processing system capable of reliably transferring data stored in an information storage device to another information storage device when the information storage device according to this embodiment is at the end of its life. Can be provided.

1 is a schematic configuration diagram of an information processing system according to a first embodiment of the present invention. FIG. 3 is an operation conceptual diagram of commands and responses of the information communication system according to the first embodiment of the present invention. 4 is a schematic flowchart at the time of authentication operation of the storage device according to the first embodiment of the invention. FIG. 3 is an operation conceptual diagram of commands and responses of the information communication system according to the first embodiment of the present invention. 4 is a schematic flowchart at the time of data read operation of the storage device according to the first embodiment of the present invention. FIG. 3 is an operation conceptual diagram of commands and responses of the information communication system according to the first embodiment of the present invention. 3 is a schematic flowchart at the time of data write operation of the storage device according to the first embodiment of the present invention. An example of the command and response set of the information communication system which concerns on the 2nd Embodiment of this invention. 1 is a schematic configuration diagram of an information processing system according to a first embodiment of the present invention. 4 is a schematic flowchart at the time of authentication operation of the storage device according to the first embodiment of the invention. 1 is a schematic configuration diagram of an information processing system according to a first embodiment of the present invention. 4 is a schematic flowchart at the time of authentication operation of the storage device according to the first embodiment of the invention. The schematic block diagram of the information processing system which concerns on the 2nd Embodiment of this invention. The outline | summary flowchart of the information processing apparatus which concerns on the 2nd Embodiment of this invention. 6 is a schematic flowchart of a storage device according to a second embodiment of the invention.

Explanation of symbols

101 ... Host,
102 ... Storage device,
103 ... non-volatile memory,
104 ... communication path,
105 ... I / F,
106 ... addition function,
107 ... comparison function,
108 ... cryptographic function,
109 ... Password,
110 ... random number value,
111 ... Encryption key,
112 ... count value,
113 ... life count value,
114 ... operation mode,
201 ... Authentication request command,
202 ... Challenge value,
203 ... Challenge value and warning notification,
204 ... Authentication rejection notification,
205 ... Response value,
206 ... Authentication success notification,
207 ... Authentication failure notification,
401 ... read request command, read password,
402: Read data, next password,
403 ... Read data, next password, warning notification,
404 ... Read rejection notice,
601: Write request command, write data, write password,
602: Write completion notification, next password,
603: Write completion notification, next password, warning notification,
604 ... write rejection notice,
901 ... operation mode register,
902: Memory I / F,
903 ... Power-on reset operation sequencer,
904 ... Data mask function,
905 ... Processing function,
1101 ... Reset generation function,
1301 User data.

Claims (11)

In an information storage device comprising a means for inputting / outputting information from an external device having a data processing function and a nonvolatile memory element having a service life,
The lifetime of the non-volatile memory element is determined by comparing the count result obtained by counting the number of updates stored in the non-volatile memory element and updated according to the processing operation of the information storage device, and a preset life prediction value. And when the result of the determination reaches the predicted life value, the processing operation of the information storage device itself is not performed by returning a rejection notification in response to the processing request from the external device. Storage device. In an information storage device comprising a means for inputting / outputting information from an external device having a data processing function and a nonvolatile memory element having a service life,
The lifetime of the non-volatile memory element is determined by comparing the count result obtained by counting the number of updates stored in the non-volatile memory element and updated according to the processing operation of the information storage device, and a preset life prediction value. An information storage device that makes a determination and does not respond to a processing request from the external device when a result of the determination reaches the estimated life value. In an information storage device comprising a means for inputting / outputting information from an external device having a data processing function and a nonvolatile memory element having a service life,
The lifetime of the non-volatile memory element is determined by comparing the count result obtained by counting the number of updates stored in the non-volatile memory element and updated according to the processing operation of the information storage device, and a preset life prediction value. Determining, and when the result of the determination reaches a predetermined remaining number of updates until reaching the estimated life value, the remaining number of accessible times until reaching the estimated life value is notified to the external device. An information storage device.   4. The information storage device according to claim 3, wherein the information storage device performs processing in response to a request from the external device, and notifies the external device of the remaining accessible number of times until the estimated life value is reached. In an information storage device comprising a means for inputting / outputting information from an external device having a data processing function and a nonvolatile memory element having a service life,
When updating the data storage area provided in the information storage device, it is determined whether there is an update failure, and if an update failure is detected, an update failure notification is transmitted to the external device, and a processing request from the external device is received. The information storage device does not perform its own processing operation. In an information storage device comprising a means for inputting / outputting information from an external device having a data processing function and a nonvolatile memory element having a service life,
An information storage device characterized by determining whether or not there is an update failure when updating an area of a data storage area provided in the information storage device, and not responding to a processing request from the external device when an update failure is detected .   In the memory area of the non-volatile memory element, an area that greatly affects the security performance of the entire system of the information storage device by fixing the memory contents is set as a life detection target of the information storage device. The information storage device according to claim 1, wherein the information storage device is an information storage device.   A random value storage area that is provided in the nonvolatile memory element and stores a random value used for device authentication between the external device and the information storage device is a detection target of the lifetime of the information storage device. The information storage device according to any one of claims 1 to 6. In response to a processing request from the external device, the state until the end of the life of the information storage device is determined, and the operation mode determined based on the determination result and stored in the nonvolatile memory is set to the number of the states. Have a number corresponding to
Whether the operation mode is detected when the information storage device is turned on, and processing request data from the external device is input to a processing function unit provided in the information storage device according to the operation mode. The information storage device according to claim 1, further comprising a data mask unit that selects the data mask unit. In response to a processing request from the external device, the state until the end of the life of the information storage device is determined, and the operation mode determined based on the result of the determination and stored in the nonvolatile memory is the number of the states Have a number corresponding to
When the operation mode is detected when the information storage device is turned on, and the operation mode is determined to be an operation mode in which a processing request from the external device cannot be accepted, a processing function unit provided in the information storage device 7. The information according to claim 1, wherein processing request data from the external device is not processed by transmitting a reset state signal to the processing function unit and maintaining the processing function unit in a reset state. Storage device. An information processing system comprising a plurality of information storage devices according to any one of claims 1 to 6,
The data stored in the memory area of one information storage device is copied to the memory area of the other information storage device, and after the one information storage device is invalidated, the other information storage device is validated. An information processing system characterized by guaranteeing data movement between a plurality of information storage devices.

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