JP6203532B2 - Semiconductor memory device and data processing system - Google Patents

Description

  The present invention relates to a semiconductor memory device and a data processing system.

  The random number is used for generating a key in an encryption algorithm. As one of the methods for obtaining a random number close to a true random number, a method of generating a random number using noise generated in a resistor or a diode has been put into practical use. However, in this method, since it is necessary to amplify low-level noise by the analog amplifier circuit, the circuit scale of the analog amplifier circuit increases, and as a result, the circuit scale of the random number generation circuit increases as a whole. Further, when the random number generation circuit is configured using an analog circuit, the difficulty of circuit design increases. Therefore, in order to avoid an increase in circuit scale and complexity in circuit design, it is desirable to use digital random numbers that can be generated by calculation.

  Pseudorandom numbers are widely used as digital random numbers. The pseudo-random number is generated by a predetermined algorithm using a seed in a random number generation circuit.

  The following Patent Document 1 discloses a random number including an indeterminate logic circuit and a uniformizing circuit for equalizing the appearance frequencies of “0” and “1” in digital values output from the indeterminate logic circuit. A generation circuit is disclosed.

Japanese Patent No. 3604673

  Since the pseudo random number is generated by calculation, if the seed and the algorithm are the same, the value of the generated pseudo random number is also the same. Therefore, when using pseudorandom numbers generated using the same seed and algorithm as an authentication code for mutual authentication or the like, there is a possibility that the security may be broken by seeing the seed and algorithm by a third party. Therefore, in order to improve the robustness of security, it is desired to easily generate a random number having non-reproducibility.

  In encrypted communication using a common key cryptosystem or the like, a session key updated for each communication is used as a common key (or a part thereof) in order to make it difficult for a third party to decrypt the key. In general, a pseudo-random number generated by a pseudo-random number generator is used as the session key. When the pseudo random number is generated using the same seed and algorithm in the pseudo random number generator, the generated pseudo random number has periodicity. Therefore, in order to avoid that the session key is decrypted by a third party using the periodicity, it is desirable to easily generate a session key using a random number that cannot be reproduced.

  The present invention has been made in view of such circumstances, and an object thereof is to obtain a semiconductor memory device capable of easily generating a random number having non-reproducibility. In addition, in a security method in which a key is exchanged between a host device and a semiconductor storage device, it is possible to easily generate a session key using a random number having non-reproducibility and data with improved security strength An object is to obtain a processing system and a semiconductor memory device.

A semiconductor memory device according to a first aspect of the present invention uses a memory array in which random number generation data used for generating random numbers is stored, and random number generation data read from the memory array as a seed. a random number generator for generating random numbers by generating algorithm, a data updating unit for updating the random number generation data, and a control unit, a semiconductor memory device Ru wherein the data updating unit, read from the memory array A second random number used after the first random number generated based on the first random number generation data by updating the first random number generation data with an algorithm different from the random number generation algorithm Generating second random number generation data for generating the second random number generation data, and writing the second random number generation data to the memory array A generation process of a random number by the random number generating unit, and the data updating unit updating process and the control unit random write processing for generating data by the random number generation data by is performed in parallel, the semiconductor memory device When power-off is requested, update processing of random number generation data by the data update unit and write processing of random number generation data by the control unit are automatically executed .

According to the semiconductor memory device of the first aspect, the data update unit updates the first random number generation data read from the memory array, thereby obtaining the second random number used after the first random number. The second random number generation data to be generated is generated, and the control unit writes the second random number generation data to the memory array. Accordingly, since the random number generation data stored in the memory array is updated to new random number generation data, a random number can be generated based on the updated random number generation data. As a result, it becomes possible to easily generate a random number having non-reproducibility.
Further, according to the semiconductor memory device of the first aspect, the random number generation unit generates a random number by a predetermined random number generation algorithm using the random number generation data read from the memory array as a seed. As described above, by generating a random number by a random number generation algorithm using the updated random number generation data as a seed, the authenticity of the random number can be ensured. Moreover, since the random number generation data read from the memory array is not used as a random number as it is, the random number generation data stored in the memory array is generated by a random number generation algorithm using the random number generation data. Even if a part of the random number is damaged or missing, it is possible to ensure the authenticity of the generated random number.
According to the semiconductor memory device of the first aspect, the random number generation process by the random number generation unit, the random number generation data update process by the data update unit, and the random number generation data write process by the control unit are: Run in parallel. Therefore, compared with the case where update processing of random number generation data is started after completion of random number generation processing or the case where random number generation processing is started after completion of writing processing of random number generation data, Time can be shortened.
In addition, according to the semiconductor memory device of the first aspect, when power-off of the semiconductor memory device is requested, update processing of random number generation data by the data update unit and write processing of random number generation data by the control unit Is automatically executed. Therefore, in the first random number generation after the power of the semiconductor memory device is turned on again, it is possible to generate a random number based on the new random number generation data written by the automatic update before power-off.

  The semiconductor memory device according to the second aspect of the present invention is the semiconductor memory device according to the first aspect, in which the data update unit is different from the first random number generation data. It is characterized by generating data.

  According to the semiconductor memory device of the second aspect, the data update unit generates second random number generation data different from the first random number generation data. Therefore, since the first random number generated based on the first random number generation data and the second random number generated based on the second random number generation data can be made different from each other, the reproduction is performed. It becomes possible to generate a random number having the impossibility.

In the semiconductor memory device according to the third aspect of the present invention, in particular, in the semiconductor memory device according to the first or second aspect, the control unit correctly writes the second random number generation data into the memory array. Up to this point, the random number generation data writing process is repeatedly executed.

According to the semiconductor memory device of the third aspect, the control unit repeatedly executes the random number generation data writing process until the second random number generation data is correctly written in the memory array. Accordingly, even if the random number generation data writing process is interrupted without being completed due to an unintended power cut, the second random number generation data writing process is resumed after the power is turned on again. The generation data can be correctly written in the memory array. As a result, when generating a random number next time, the random number generation unit can generate a random number based on the second random number generation data, and thus it is possible to ensure the non-reproducibility of the random number.

The semiconductor memory device according to the fourth aspect of the present invention is the semiconductor memory device according to any one of the first to third aspects, and in particular, the memory array includes a semiconductor memory as an initial value of random number generation data. A characteristic value that is different for each device is stored.

According to the semiconductor memory device of the fourth aspect, the memory array stores different eigenvalues for each semiconductor memory device as the initial value of the random number generation data. Therefore, even in the initial random number generation, a random number different for each semiconductor memory device can be generated by the random number generation unit.

The semiconductor memory device according to the fifth aspect of the present invention is the semiconductor memory device according to any one of the first to fourth aspects, in particular, the random number generation data is a host device in the memory area of the memory array. It is stored in an area where access from is prohibited.

According to the semiconductor memory device of the fifth aspect, the random number generation data is stored in an area where access from the host device is prohibited in the memory area of the memory array. Therefore, an attacker cannot read random number generation data from the memory array via the host device or overwrite the random number generation data stored in the memory array with invalid data, thus improving security. It becomes possible.

The semiconductor memory device according to the sixth aspect of the present invention is the semiconductor memory device according to any one of the first to fifth aspects, particularly when the power of the semiconductor memory device is turned on. Random number generation data update processing and random number generation data write processing by the control unit are automatically executed.

According to the semiconductor memory device of the sixth aspect, when the power of the semiconductor memory device is turned on, the update process of the random number generation data by the data update unit and the write process of the random number generation data by the control unit are automatically performed. To be executed. Therefore, in the first random number generation after the power is turned on, it is possible to generate a random number based on the new random number generation data written by the automatic update.

According to a seventh aspect of the present invention, there is provided a data processing system, comprising: exchanging a key between a host device and the host device, decrypting a command received from the host device using the key; A semiconductor storage device that encrypts data to be transmitted to the device using the key, the semiconductor storage device transmitting / receiving data to / from the host device, key generation data used for key generation, Is transmitted to the host device in response to the current key request by generating a random number by a predetermined random number generation algorithm using the memory array in which is stored and the key generation data read from the memory array as a seed. A key generation unit that generates a key to be generated, a data update unit that updates data for key generation, and a control unit. The key generation unit generates a key to be transmitted to the host device in response to the current key request based on the first key generation data stored in the memory array at that time The control unit encrypts the key generated by the key generation unit and transmits the encrypted key to the host device, and the data update unit differs from the random number generation algorithm in the first key generation data. Updating by the algorithm generates second key generation data for generating a key to be transmitted to the host device in response to a key request after this time, and the control unit generates the second key The generation data is written into the memory array, the key generation process by the key generation unit and the key transmission process by the control unit, the key generation data update process by the data update unit, and the control unit. The writing process of the key generation data, is characterized in that are executed in parallel.

According to the data processing system of the seventh aspect, when the semiconductor storage device receives a key request from the host device, the data update unit updates the first key generation data to thereby update the key after this time. The controller generates second key generation data for generating a key to be transmitted to the host device in response to the request, and the control unit writes the second key generation data generated by the data update unit to the memory array. . Therefore, each time the semiconductor memory device receives a key request from the host device, the key generation data stored in the memory array is updated to new key generation data, and the key generation unit is updated each time. Generate a key based on the data. As a result, in a security method in which a common key is exchanged between a host device and a semiconductor storage device, a common key using a non-reproducible random number can be easily generated, and security strength can be improved. Become.
According to the data processing system of the eighth aspect, the random number generator generates a random number by a predetermined random number generation algorithm using the key generation data read from the memory array as a seed. A key to be transmitted to the host device is generated in response to the key request. As described above, by using the random number generated by the random number generation algorithm using the key generation data updated every time as a seed, it is possible to ensure the authenticity of the common key. Moreover, since the key generation data read from the memory array is not used as it is as a common key, but a random number generated by a random number generation algorithm using the key generation data is used as a common key, it is stored in the memory array. Even if a part of the generated key generation data is damaged or missing, it is possible to ensure the authenticity of the generated common key.
According to the data processing system of the seventh aspect, the key generation process by the key generation unit and the key transmission process by the control unit, the key generation data update process by the data update unit, and the key generation by the control unit The data writing process is executed in parallel. Therefore, when the key generation data update process is started after the key transmission process is completed, or when the key generation process is started after the key generation data write process is completed, the entire process is required. Time can be shortened.

The data processing system according to an eighth aspect of the present invention is the data processing system according to the seventh aspect, in particular, wherein the data update unit is different from the first key generation data. It is characterized by generating data.

According to the data processing system of the eighth aspect, the data update unit generates second key generation data different from the first key generation data. Accordingly, the first key generated based on the first key generation data and the second key generated based on the second key generation data can be made different from each other, and thus reproduced. It becomes possible to generate a common key using a random number having impossibility.

In the data processing system according to the ninth aspect of the present invention, in particular, in the data processing system according to the seventh or eighth aspect, the control unit correctly writes the second key generation data to the memory array. Up to this point, the key generation data writing process is repeatedly executed.

According to the data processing system of the ninth aspect, the control unit repeatedly executes the key generation data writing process until the second key generation data is correctly written to the memory array. Accordingly, even if the key generation data writing process is interrupted without being completed due to an unintended power interruption, the second key can be recovered by restarting the key generation data writing process after the power is turned on again. The generation data can be correctly written in the memory array. As a result, the key generation unit can generate a key based on the second key generation data in response to the next key request from the host device, so that it is possible to ensure the non-reproducibility of the key. Become.

A data processing system according to a tenth aspect of the present invention is the data processing system according to any one of the seventh to ninth aspects, in particular, the semiconductor array includes a semiconductor memory as an initial value of key generation data. A characteristic value that is different for each device is stored.

According to the data processing system of the tenth aspect, the memory array stores different eigenvalues for each semiconductor memory device as the initial value of the key generation data. Therefore, even for the first key request from the host device, a key different for each semiconductor memory device can be generated by the key generation unit.

The data processing system according to an eleventh aspect of the present invention is the data processing system according to any one of the seventh to tenth aspects, in particular, the key generation data is the host in the storage area of the memory array. It is stored in an area where access from the apparatus is prohibited.

According to the data processing system of the eleventh aspect, the key generation data is stored in an area where access from the host device is prohibited in the storage area of the memory array. Therefore, the attacker cannot read out the key generation data from the memory array via the host device or overwrite the key generation data stored in the memory array with invalid data, thus improving security. It becomes possible.

A data processing system according to a twelfth aspect of the present invention is the data processing system according to any one of the seventh to eleventh aspects, particularly when the power of the semiconductor memory device is turned on. The key generation data update process and the key generation data write process by the control unit are automatically executed.

According to the data processing system of the twelfth aspect, when the power of the semiconductor memory device is turned on, the key generation data update process by the data update unit and the key generation data write process by the control unit are automatically performed. To be executed. Therefore, for the first key request after the power is turned on, a key generated based on the new key generation data written by the automatic update can be transmitted to the host device.

A data processing system according to a thirteenth aspect of the present invention is the data processing system according to any one of the seventh to twelfth aspects, particularly when the power to the semiconductor memory device is requested to be cut off. The key generation data update process by the control unit and the key generation data write process by the control unit are automatically executed.

According to the data processing system of the thirteenth aspect, when the semiconductor memory device is requested to be turned off, the key generation data update process by the data update unit and the key generation data write process by the control unit are automatically performed. Is executed automatically. Therefore, for the first key request after the power of the semiconductor memory device is turned on again, a key generated based on the new key generation data written by the automatic update before the power is turned off is stored in the host device. Can be sent to.

A semiconductor memory device according to a fourteenth aspect of the present invention uses a memory array storing key generation data used for key generation, and a predetermined random number using the key generation data read from the memory array as a seed. A key generation unit that generates a key by generating a random number using a generation algorithm, a data update unit that updates key generation data, and a control unit, wherein the key generation unit is stored in the memory array. A first key is generated based on the first key generation data, and the data update unit updates the first key generation data by an algorithm different from the random number generation algorithm. Generating second key generation data for generating a second key to be used after the first key, and the control unit stores the second key generation data in the memory array The key generation processing by the key generation unit, the key generation data update processing by the data update unit, and the key generation data write processing by the control unit are executed in parallel. To do.

According to the semiconductor memory device in the fourteenth aspect, the data updating unit updates the first key generation data, thereby generating the second key used after the first key. The second key generation data is generated, and the control unit writes the second key generation data generated by the data update unit to the memory array. Therefore, the key generation data stored in the memory array is updated to new key generation data, and in the next key generation, the key generation unit generates a key based on the updated key generation data. As a result, it is possible to easily generate a key using a random number that cannot be reproduced, and to improve the security strength.
According to the semiconductor memory device of the fourteenth aspect, the random number generator generates a random number by using a predetermined random number generation algorithm using the key generation data read from the memory array as a seed. Generate. In this way, it is possible to ensure the authenticity of the key by using the random number generated by the random number generation algorithm using the updated key generation data as a seed. Moreover, since the key generation data read from the memory array is not used as a key as it is, but a random number generated by a random number generation algorithm using the key generation data is used as a key, it is stored in the memory array. Even when a part of the key generation data is damaged or missing, it is possible to ensure the authenticity of the generated key.
According to the semiconductor storage device of the fourteenth aspect, the key generation process by the key generation unit, the key generation data update process by the data update unit, and the key generation data write process by the control unit are: Run in parallel. Therefore, when the key generation data update process is started after the key transmission process is completed, or when the key generation process is started after the key generation data write process is completed, the entire process is required. Time can be shortened.

The semiconductor memory device according to a fifteenth aspect of the present invention is the semiconductor memory device according to the fourteenth aspect, in which the data updating unit is different from the first key generation data. It is characterized by generating data.

According to the semiconductor memory device in the fifteenth aspect, the data update unit generates second key generation data different from the first key generation data. Accordingly, the first key generated based on the first key generation data and the second key generated based on the second key generation data can be made different from each other, and thus reproduced. It becomes possible to generate a key using a random number having an impossibility.

  According to the present invention, it is possible to obtain a semiconductor memory device that can easily generate a random number having non-reproducibility. Further, in a security method in which a key is exchanged between a host device and a semiconductor storage device, it is possible to easily generate a key using a non-reproducible random number and to improve data security A system and a semiconductor memory device can be obtained.

It is a figure showing roughly the composition of the data processing system concerning an embodiment of the invention. 1 is a diagram showing a configuration of a semiconductor memory device according to a first embodiment of the present invention. It is a figure which shows the structure of a random number generation part. It is a figure which shows the structure of a data update part. It is a figure which shows the structure of the semiconductor memory device based on Embodiment 2 of this invention. It is a figure which shows the structure of a data update part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

  FIG. 1 is a diagram schematically showing a configuration of a data processing system 100 according to an embodiment of the present invention. The data processing system 100 includes a host device 1 and a semiconductor storage device 2. The semiconductor memory device 2 is, for example, a memory card that can be detachably connected to the host device 1. The data processing system 100 exchanges a common key as a session key between the host device 1 and the semiconductor storage device 2, thereby encrypting and decrypting commands and data transmitted and received between the two (a common method) Adopt key encryption method).

<Embodiment 1>
FIG. 2 is a diagram showing a configuration of the semiconductor memory device 2A according to the first embodiment of the present invention. As shown in the connection relationship of FIG. 2, the semiconductor memory device 2A includes a host interface 11, an encryption / decryption unit 12, a control unit 13, a random number generation unit 14A, a data update unit 15A, a memory interface 16, and a memory array 17. It is prepared for. In the first embodiment, the random number generation unit 14A functions as a key generation unit. The memory array 17 is configured using, for example, a NAND flash memory. However, the present invention is not limited to this example, and the memory array 17 may be configured using a NOR flash memory or the like.

  The memory array 17 includes a prohibited area 20 in which access from the host device 1 is prohibited in a part of the entire storage area. That is, the host device 1 cannot specify the address of the prohibited area 20 as the data read destination and write destination when reading and writing data to the memory array 17. The prohibited area 20 stores random number generation data X (seed in the first embodiment). Of the entire storage area of the memory array 17, in the area other than the prohibited area 20, arbitrary data (image, sound, text, code, management information, etc.) transmitted and received between the host device 1 and the semiconductor storage device 2A Is remembered.

  FIG. 3 is a diagram illustrating a configuration of the random number generation unit 14A. As shown in FIG. 3, the random number generation unit 14 </ b> A has a random number generator 21. The random number generator 21 uses the random number generation data read from the prohibited area 20 as a seed, and uses a pseudo-random number generation algorithm, a hash function, a common key encryption algorithm, a public key encryption algorithm, etc. A session key (common key) that is a digital random number is generated by an arbitrary random number generation algorithm (or a combination thereof).

  FIG. 4 is a diagram illustrating a configuration of the data update unit 15A. As shown in FIG. 4, the data update unit 15 </ b> A has a counter 22. The counter 22 generates updated random number generation data by incrementing or decrementing the random number generation data read from the prohibited area 20. According to the configuration shown in FIG. 4, it is possible to realize update processing of random number generation data with a simple configuration using the counter 22. Note that the data update unit 15A may be configured using a random number generator similar to the random number generation unit 14A. In this case, the same random number generator may be shared by the random number generation unit 14A and the data update unit 15A.

  The operation of the semiconductor memory device 2A according to the first embodiment will be described below with reference to FIGS.

  When the system is turned on, the control unit 13 first sets (initializes) the pre-installed key K0 in the encryption / decryption unit 12. Also in the host device 1, a key K0 common to the semiconductor memory device 2A is set. The forbidden area 20 stores the latest random number generation data X1 stored in the forbidden area 20 when the system was previously shut down. At the time of shipment of the semiconductor memory device 2A from the factory, a unique value that differs for each semiconductor memory device 2A is stored in the prohibited area 20 as an initial value of the random number generation data X.

  For example, before the host device 1 reads data stored in the memory array 17, the host device 1 transmits a key request to the semiconductor memory device 2A in order to update the common key. Specifically, after generating the random number generation command C0A for requesting the key update, the host device 1 generates the encrypted random number generation command C0A by encrypting the random number generation command C0A using the key K0. To do. Then, the encrypted random number generation command C0A is transmitted to the semiconductor memory device 2A.

  The encrypted random number generation command C0A is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encrypted random number generation command C0A using the key K0, and inputs the decrypted random number generation command C0A to the control unit 13.

  Next, the control unit 13 generates a read request R1 for reading the random number generation data X1 from the prohibited area 20 based on the random number generation command C0A.

  The read request R1 is input to the memory array 17 via the memory interface 16, and the random number generation data X1 stored in the prohibited area 20 at that time is read from the memory array 17.

  The random number generation data X1 is input to the random number generation unit 14A and the data update unit 15A via the memory interface 16.

  Next, the random number generation unit 14A generates a session key K1 to be transmitted to the host device 1 in response to the current key request based on the random number generation data X1. Specifically, the random number generator 21 generates a session key K1 by generating a random number using a random number generation algorithm such as the pseudo-random number generation algorithm using the random number generation data X1 as a seed. The random number generation unit 14A inputs the session key K1 generated based on the random number generation data X1 to the control unit 13. Next, the control unit 13 inputs the session key K1 to the encryption / decryption unit 12. Next, the encryption / decryption unit 12 encrypts the session key K1 using the key K0. Next, the control unit 13 transmits the encrypted session key K1 generated by the encryption / decryption unit 12 to the host device 1 via the host interface 11.

  Further, the data updating unit 15A updates the random number generation data X1, thereby generating a random number for generating a session key K2 to be transmitted to the host device 1 in response to the next (or later, the same applies hereinafter) key request. Generation data X2 is generated. Specifically, the counter 22 generates random number generation data X2 different from the random number generation data X1 by incrementing or decrementing the random number generation data X1. The data updating unit 15A inputs the updated random number generation data X2 to the control unit 13. Next, the control unit 13 generates a write request W2 for writing the random number generation data X2 to the prohibited area 20. The write request W2 is input to the memory array 17 via the memory interface 16, and the random number generation data X1 stored in the prohibited area 20 is overwritten by the updated random number generation data X2. Here, the control unit 13 repeatedly executes the overwrite processing of the random number generation data X2 until the random number generation data X1 stored in the prohibited area 20 is correctly overwritten by the random number generation data X2. Specifically, the control unit 13 reads the random number generation data X2 from the prohibited area 20 after the overwrite process is completed, and the content of the random number generation data X2 is the content of the random number generation data X2 input from the data update unit 15A. It is determined (verify) whether or not the same. Then, the random number generation data X2 is overwritten repeatedly until the contents of both data are the same. As the value of the random number generation data updated by the data updating unit 15A, it is desirable to avoid the value used in the past and always adopt an unused value. However, when the counter value has an upper limit, etc. A value used in the past may be used for. Further, a plurality of areas for writing updated random number generation data may be provided in the prohibited area 20 in order to avoid occurrence of defects due to concentration of accesses to the same area of the memory array 17.

  Note that the generation process of the session key K1 by the random number generation unit 14A, the transmission process of the session key K1 to the host device 1 by the control unit 13, the update process of the random number generation data X2 by the data update unit 15A, and the random number by the control unit 13 The generation data X2 overwriting process is executed in parallel. That is, the execution of the session key K1 generation process and the random number generation data X2 update process starts simultaneously. Therefore, for example, when the write latency period accompanying the overwriting process of the random number generation data X2 is long, the session key K1 generation process and the session key K1 transmission process are executed within the write latency period.

  Next, the host apparatus 1 acquires the updated session key K1 by decrypting the encrypted session key K1 using the key K0.

  Next, the host device 1 generates an initialization command C0B for requesting setting (initialization) of the session key K1, and then encrypts the initialization command C0B using the key K0, thereby Command is generated. Then, the encryption initialization command C0B is transmitted to the semiconductor memory device 2A.

  The encryption initialization command C0B is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encryption initialization command C0B using the key K0, and inputs the decrypted initialization command C0B to the control unit 13.

  Next, the control unit 13 sets the session key K1 in the encryption / decryption unit 12 by the setting signal D1 based on the initialization command C0B. Also in the host device 1, a session key K1 common to the semiconductor memory device 2A is set. Through the above processing, the common key of the host device 1 and the semiconductor memory device 2A is updated from the key K0 to the session key K1. Thereafter, encrypted communication of commands and data is executed between the host device 1 and the semiconductor storage device 2A using the session key K1.

  Thereafter, when performing encrypted communication by re-updating the session key, the host device 1 transmits a key request to the semiconductor memory device 2A in order to update the common key. Specifically, the host device 1 transmits an encrypted random number generation command C1A to the semiconductor memory device 2A.

  The encrypted random number generation command C1A is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encrypted random number generation command C1A using the session key K1, and inputs the decrypted random number generation command C1A to the control unit 13.

  Next, the control unit 13 generates a read request R2 for reading the random number generation data X2 from the prohibited area 20 based on the random number generation command C1A.

  The read request R2 is input to the memory array 17 via the memory interface 16, and the random number generation data X2 stored in the prohibited area 20 at that time is read from the memory array 17.

  The random number generation data X2 is input to the random number generation unit 14A and the data update unit 15A via the memory interface 16.

  Next, the random number generation unit 14A generates a session key K2 to be transmitted to the host device 1 in response to the current key request based on the random number generation data X2. The random number generation unit 14A inputs the session key K2 generated based on the random number generation data X2 to the control unit 13. Next, the control unit 13 inputs the session key K2 to the encryption / decryption unit 12. Next, the encryption / decryption unit 12 encrypts the session key K2 using the session key K1. Next, the control unit 13 transmits the encrypted session key K <b> 2 generated by the encryption / decryption unit 12 to the host device 1 via the host interface 11.

  In addition, the data updating unit 15A updates the random number generation data X2, thereby generating random number generation data X3 for generating a session key K3 to be transmitted to the host device 1 in response to the next key request. The data updating unit 15A inputs the updated random number generation data X3 to the control unit 13. Next, the control unit 13 generates a write request W3 for writing the random number generation data X3 in the prohibited area 20. The write request W3 is input to the memory array 17 via the memory interface 16, and the random number generation data X2 stored in the prohibited area 20 is overwritten by the updated random number generation data X3. Here, the control unit 13 repeatedly executes the overwriting process of the random number generation data X3 until the random number generation data X2 stored in the prohibited area 20 is correctly overwritten by the random number generation data X3.

  Next, the host apparatus 1 acquires the updated session key K2 by decrypting the encrypted session key K2 using the session key K1.

  Next, the host device 1 generates an initialization command C1B for requesting the setting (initialization) of the session key K2, and then encrypts the initialization command C1B by using the session key K1. An initialization command C1B is generated. Then, the encryption initialization command C1B is transmitted to the semiconductor memory device 2A.

  The encryption initialization command C1B is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encryption initialization command C1B using the session key K1, and inputs the decrypted initialization command C1B to the control unit 13.

  Next, the control unit 13 sets the session key K2 in the encryption / decryption unit 12 by the setting signal D2 based on the initialization command C1B. Also in the host device 1, a session key K2 common to the semiconductor memory device 2A is set. Through the above processing, the common key of the host device 1 and the semiconductor memory device 2A is updated from the session key K1 to the session key K2. Thereafter, encrypted communication of commands and data is executed between the host device 1 and the semiconductor memory device 2A using the session key K2.

  Thereafter, similarly, each time a key request is transmitted from the host device 1 to the semiconductor memory device 2A, the common key is updated in the host device 1 and the semiconductor memory device 2A.

<Embodiment 2>
FIG. 5 is a diagram showing a configuration of the semiconductor memory device 2B according to the second embodiment of the present invention. As shown in the connection relationship of FIG. 5, the semiconductor memory device 2B includes a host interface 11, an encryption / decryption unit 12, a control unit 13, a data update unit 15B, a memory interface 16, and a memory array 17. Yes. In the second embodiment, the data update unit 15B functions as a key generation unit. In the prohibited area 20 of the memory array 17, random number generation data Y (random numbers in the second embodiment) is stored.

  FIG. 6 is a diagram illustrating a configuration of the data update unit 15B. As shown in FIG. 6, the data update unit 15B has a random number generator 23. The random number generator 23 uses the random number generation data read from the prohibited area 20 as a seed, such as a pseudo random number generation algorithm, a hash function, a common key encryption algorithm, or a public key encryption algorithm. New random number generation data that is a digital random number is generated by an arbitrary random number generation algorithm (or a combination thereof). Further, the data updating unit 15B outputs the random number generation data read from the prohibited area 20 as it is as a session key.

  Hereinafter, the operation of the semiconductor memory device 2B according to the second embodiment will be described with reference to FIGS.

  When the system is turned on, the control unit 13 first sets (initializes) the pre-installed key K0 in the encryption / decryption unit 12. Also in the host device 1, a key K0 common to the semiconductor memory device 2B is set. The forbidden area 20 stores the latest random number generation data Y1 stored in the forbidden area 20 when the system was previously shut down. At the time of shipment of the semiconductor memory device 2B from the factory, a unique value that is different for each semiconductor memory device 2B is stored in the prohibited area 20 as an initial value of the random number generation data Y.

  For example, before the host device 1 reads data stored in the memory array 17, the host device 1 transmits a key request to the semiconductor memory device 2B in order to update the common key. Specifically, after generating the random number generation command C0A for requesting the key update, the host device 1 generates the encrypted random number generation command C0A by encrypting the random number generation command C0A using the key K0. To do. Then, the encrypted random number generation command C0A is transmitted to the semiconductor memory device 2B.

  The encrypted random number generation command C0A is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encrypted random number generation command C0A using the key K0, and inputs the decrypted random number generation command C0A to the control unit 13.

  Next, the control unit 13 generates a read request R1 for reading the random number generation data Y1 from the prohibited area 20 based on the random number generation command C0A.

  The read request R1 is input to the memory array 17 via the memory interface 16, and the random number generation data Y1 stored in the prohibited area 20 at that time is read from the memory array 17.

  The random number generation data Y1 is input to the data update unit 15B via the memory interface 16.

  Next, the data updating unit 15B generates a session key K1 to be transmitted to the host device 1 in response to the current key request based on the random number generation data Y1. In the second embodiment, since the random number generation data Y1 itself is a random number, the data update unit 15B sends the random number generation data Y1 read from the memory array 17 as it is to the host device 1 in response to the current key request. Output as the session key K1 to be transmitted. The data updating unit 15B inputs the random number generation data Y1 to the control unit 13 as the session key K1. Next, the control unit 13 inputs the session key K1 to the encryption / decryption unit 12. Next, the encryption / decryption unit 12 encrypts the session key K1 using the key K0. Next, the control unit 13 transmits the encrypted session key K1 generated by the encryption / decryption unit 12 to the host device 1 via the host interface 11.

  In addition, the data update unit 15B generates random number generation data Y2 for generating a session key K2 to be transmitted to the host apparatus 1 in response to the next key request by updating the random number generation data Y1. Specifically, the random number generator 23 uses the random number generation data Y1 as a seed to generate new random number generation data Y2 by a random number generation algorithm such as the pseudo random number generation algorithm. The data updating unit 15B inputs the updated random number generation data Y2 to the control unit 13. Next, the control unit 13 generates a write request W2 for writing the random number generation data Y2 to the prohibited area 20. The write request W2 is input to the memory array 17 via the memory interface 16, and the random number generation data Y1 stored in the prohibited area 20 is overwritten with the updated random number generation data Y2. Here, the control unit 13 repeatedly executes the overwriting process of the random number generation data Y2 until the random number generation data Y1 stored in the prohibited area 20 is correctly overwritten by the random number generation data Y2.

  Next, the host apparatus 1 acquires the updated session key K1 by decrypting the encrypted session key K1 using the key K0.

  Next, the host device 1 generates an initialization command C0B for requesting setting (initialization) of the session key K1, and then encrypts the initialization command C0B using the key K0, thereby Command is generated. Then, the encryption initialization command C0B is transmitted to the semiconductor memory device 2B.

  The encryption initialization command C0B is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encryption initialization command C0B using the key K0, and inputs the decrypted initialization command C0B to the control unit 13.

  Next, the control unit 13 sets the session key K1 in the encryption / decryption unit 12 by the setting signal D1 based on the initialization command C0B. Also in the host device 1, a session key K1 common to the semiconductor memory device 2B is set. Through the above processing, the common key of the host device 1 and the semiconductor memory device 2B is updated from the key K0 to the session key K1. Thereafter, encrypted communication of commands and data is executed between the host device 1 and the semiconductor memory device 2B using the session key K1.

  Thereafter, when performing encrypted communication by re-updating the session key, the host device 1 transmits a key request to the semiconductor memory device 2B in order to update the common key. Specifically, the host device 1 transmits an encrypted random number generation command C1A to the semiconductor memory device 2B.

  The encrypted random number generation command C1A is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encrypted random number generation command C1A using the session key K1, and inputs the decrypted random number generation command C1A to the control unit 13.

  Next, the control unit 13 generates a read request R2 for reading the random number generation data Y2 from the prohibited area 20 based on the random number generation command C1A.

  The read request R2 is input to the memory array 17 via the memory interface 16, and the random number generation data Y2 stored in the prohibited area 20 at that time is read from the memory array 17.

  The random number generation data Y2 is input to the data update unit 15B via the memory interface 16.

  Next, the data updating unit 15B generates a session key K2 to be transmitted to the host device 1 in response to the current key request based on the random number generation data Y2. The data update unit 15B inputs the session key K2 generated based on the random number generation data Y2 to the control unit 13. Next, the control unit 13 inputs the session key K2 to the encryption / decryption unit 12. Next, the encryption / decryption unit 12 encrypts the session key K2 using the session key K1. Next, the control unit 13 transmits the encrypted session key K <b> 2 generated by the encryption / decryption unit 12 to the host device 1 via the host interface 11.

  Further, the data updating unit 15B updates the random number generation data Y2, thereby generating random number generation data Y3 for generating a session key K3 to be transmitted to the host device 1 in response to the next key request. The data updating unit 15B inputs the updated random number generation data Y3 to the control unit 13. Next, the control unit 13 generates a write request W3 for writing the random number generation data Y3 in the prohibited area 20. The write request W3 is input to the memory array 17 via the memory interface 16, and the random number generation data Y2 stored in the prohibited area 20 is overwritten by the updated random number generation data Y3. Here, the control unit 13 repeatedly executes the overwriting process of the random number generation data Y3 until the random number generation data Y2 stored in the prohibited area 20 is correctly overwritten by the random number generation data Y3.

  Next, the host apparatus 1 acquires the updated session key K2 by decrypting the encrypted session key K2 using the session key K1.

  Next, the host device 1 generates an initialization command C1B for requesting the setting (initialization) of the session key K2, and then encrypts the initialization command C1B by using the session key K1. An initialization command C1B is generated. Then, the encryption initialization command C1B is transmitted to the semiconductor memory device 2B.

  The encryption initialization command C1B is input to the encryption / decryption unit 12 via the host interface 11. Next, the encryption / decryption unit 12 decrypts the encryption initialization command C1B using the session key K1, and inputs the decrypted initialization command C1B to the control unit 13.

  Next, the control unit 13 sets the session key K2 in the encryption / decryption unit 12 by the setting signal D2 based on the initialization command C1B. Also in the host device 1, a session key K2 common to the semiconductor memory device 2B is set. Through the above processing, the common key of the host device 1 and the semiconductor storage device 2B is updated from the session key K1 to the session key K2. Thereafter, encrypted communication of commands and data is executed between the host device 1 and the semiconductor memory device 2B using the session key K2.

  Thereafter, similarly, every time a key request is transmitted from the host device 1 to the semiconductor memory device 2B, the common key is updated in the host device 1 and the semiconductor memory device 2B.

<Modification>
In the first and second embodiments, when the semiconductor storage devices 2A and 2B receive a key request from the host device 1, the update processing of the random number generation data by the data update units 15A and 15B and the random number generation by the control unit 13 are performed. The data was overwritten.

  In addition, when the system is turned on, immediately after the power is turned on, the random number generation data is updated and overwritten automatically (that is, without waiting for reception of a random number generation command from the host device 1). May be executed.

  In addition to this, when the power-off of the system is requested, the random number generation data update process and the overwrite process may be automatically executed immediately before the power-off.

<Summary>
According to the semiconductor memory devices 2A and 2B according to the first and second embodiments, the data updating units 15A and 15B update the first random number generation data X1 and Y1 read from the memory array 17 to Second random number generation data X2 and Y2 for generating a second random number (session key K2) used after the first random number (session key K1) are generated. Further, the control unit 13 overwrites the first random number generation data X1 and Y1 stored in the memory array 17 with the second random number generation data X2 and Y2. Accordingly, since the random number generation data X1 and Y1 stored in the memory array 17 are updated to new random number generation data X2 and Y2, random numbers can be generated based on the updated random number generation data. . As a result, it becomes possible to easily generate a random number having non-reproducibility.

  Similarly, according to the data processing system 100 according to the first and second embodiments, when the semiconductor storage devices 2A and 2B receive a key request from the host device 1, the data updating units 15A and 15B generate the first random number. The second random number generation data X2, for generating the session key K2 to be transmitted to the host device 1 in response to the key request after this time by updating the data (key generation data) X1, Y1 Y2 is generated. Further, the control unit 13 overwrites the first random number generation data X1 and Y1 stored in the memory array 17 with the second random number generation data X2 and Y2 generated by the data update units 15A and 15B. . Therefore, each time the semiconductor memory devices 2A and 2B receive a key request from the host device 1, the random number generation data stored in the memory array 17 is updated to new random number generation data, and the random number generation unit (key generation unit) ) 14A and 14B generate a session key based on random number generation data updated every time. As a result, in a security method in which a common key is exchanged between the host device 1 and the semiconductor storage devices 2A and 2B, a common key using a random number having non-reproducibility can be easily generated, and the security strength is improved. It becomes possible.

  In addition, according to the semiconductor memory devices 2A and 2B and the data processing system 100 according to the first and second embodiments, the data update units 15A and 15B are different from the first random number generation data X1 and Y1. Random number generation data X2 and Y2 are generated. Therefore, the first random number generated based on the first random number generation data X1, Y1 and the second random number generated based on the second random number generation data X2, Y2 are made different from each other. Therefore, it becomes possible to generate a random number having non-reproducibility.

  Further, according to the semiconductor memory device 2A according to the first embodiment, the random number generator 21 uses the random number generation data X1 and X2 read from the memory array 17 as a seed, and generates a random number by a predetermined random number generation algorithm. Generate. As described above, by generating a random number by a random number generation algorithm using the updated random number generation data X1 and X2 as a seed, it is possible to ensure the authenticity of the random number. In addition, since the random number generation data X1 and X2 read from the memory array 17 are not used as random numbers as they are, random numbers are generated by a random number generation algorithm using the random number generation data X1 and X2. Even when a part of the stored random number generation data X1, X2 is damaged or missing, it is possible to ensure the authenticity of the generated random number.

  Similarly, according to the data processing system 100 according to the first embodiment, the random number generator 21 uses the random number generation data X1 and X2 read from the memory array 17 as a seed, and generates a random number by a predetermined random number generation algorithm. By generating, session keys K1 and K2 to be transmitted to the host device 1 in response to the current key request are generated. As described above, by using the random number generated by the random number generation algorithm using the random number generation data X1 and X2 updated every time as a seed, the authenticity of the common key can be ensured. In addition, the random number generation data X1 and X2 read from the memory array 17 are not used as they are as the common key, but the random numbers generated by the random number generation algorithm using the random number generation data X1 and X2 are used as the common key. Therefore, even if a part of the random number generation data X1 and X2 stored in the memory array 17 is damaged or missing, it is possible to ensure the authenticity of the generated common key. .

  Also, according to the semiconductor memory devices 2A and 2B according to the first and second embodiments, random number generation processing by the random number generation units 14A and 14B, and random number generation data update processing and control by the data update units 15A and 15B. The random number generation data overwrite process by the unit 13 is executed in parallel. Therefore, compared with the case where the update process of the random number generation data is started after the random number generation process is completed or the case where the random number generation process is started after the overwriting process of the random number generation data is completed, the entire process is required. Time can be shortened.

  Similarly, according to the data processing system 100 according to the first and second embodiments, the session key generation process by the random number generation units 14A and 14B, the session key transmission process by the control unit 13, and the data update units 15A and 15B. The update process of the random number generation data and the overwrite process of the random number generation data by the control unit 13 are executed in parallel. Therefore, when the update process of random number generation data is started after the session key transmission process is completed, or when the session key generation process is started after the overwrite process of the random number generation data is completed, the entire process It is possible to shorten the required time.

  Further, according to the semiconductor memory device 2B according to the second embodiment, the memory array 17 stores random numbers as the random number generation data Y1 and Y2. Therefore, by using the updated random number generation data Y1 and Y2 as random numbers, it is possible to ensure the authenticity of the random numbers. In addition, the random number generation data Y1 and Y2 read from the memory array 17 can be used as random numbers as they are, and the random number generation processing using the random number generation data Y1 and Y2 as a seed is unnecessary. It is possible to shorten the time required to do this.

  Similarly, according to the data processing system 100 according to the second embodiment, the data update unit 15B (key generation unit) corresponds the key generation data Y1 and Y2 read from the memory array 17 to the current key request. And generated as session keys K1 and K2 to be transmitted to the host device 1. As described above, by using the random number generation data Y1 and Y2 updated every time as the common key, it is possible to ensure the authenticity of the common key. Moreover, since the random number generation data Y1 and Y2 read from the memory array 17 can be used as they are as a common key, and random number generation processing using the random number generation data Y1 and Y2 as a seed is unnecessary, the host device It is possible to reduce the time required from receiving the key request from 1 to transmitting the common key to the host device 1.

  Further, according to the semiconductor memory device 2B and the data processing system 100 according to the second embodiment, the random number generator 23 uses the first random number generation data Y1 and Y2 read from the memory array 17 as a seed, Second random number generation data Y2 and Y3 are generated by generating random numbers using a predetermined random number generation algorithm. As described above, by generating the second random number generation data Y2 and Y3 by the random number generation algorithm using the first random number generation data Y1 and Y2 as a seed, the random number generation data used as the random number and the common key is used. It becomes possible to guarantee the authenticity of the data.

  Also, according to the semiconductor memory devices 2A and 2B according to the first and second embodiments, the control unit 13 uses the first random number generation data X1 and Y1 stored in the memory array 17 as the second random number generator. The random number generation data is overwritten repeatedly until it is overwritten correctly by the data X2 and Y2. Therefore, even if the random number generation data overwriting process is interrupted without being completed due to an unintended power interruption, the random number generation data overwriting process is resumed after the power is turned on again. The stored first random number generation data X1 and Y1 can be correctly overwritten by the second random number generation data X2 and Y2. As a result, when generating a random number next time, the random number generation units 14A and 14B can generate a random number based on the second random number generation data X2 and Y2, thus ensuring the non-reproducibility of the random number. It becomes possible.

  Similarly, according to the data processing system 100 according to the first and second embodiments, the control unit 13 uses the first random number generation data X1 and Y1 stored in the memory array 17 as the second random number generation data. The random number generation data is overwritten repeatedly until it is correctly overwritten by X2 and Y2. Therefore, even if the random number generation data overwriting process is interrupted without being completed due to an unintended power interruption, the random number generation data overwriting process is resumed after the power is turned on again. The stored first random number generation data X1 and Y1 can be correctly overwritten by the second random number generation data X2 and Y2. As a result, the random number generators 14A and 14B can generate the session key K2 based on the second random number generation data X2 and Y2 in response to the next key request from the host device 1, and thus the key cannot be reproduced. It is possible to ensure the possibility.

  Further, according to the semiconductor memory devices 2A and 2B according to the first and second embodiments, the memory array 17 stores different eigenvalues for the semiconductor memory devices 2A and 2B as the initial values of the random number generation data. Yes. Therefore, even in the initial random number generation, it is possible to generate different random numbers for the semiconductor memory devices 2A and 2B by the random number generation units 14A and 14B.

  Similarly, according to the data processing system 100 according to the first and second embodiments, the memory array 17 stores different eigenvalues for the semiconductor memory devices 2A and 2B as initial values of random number generation data. Accordingly, even for the first key request from the host device 1, it is possible to generate different session keys for the semiconductor memory devices 2A and 2B by the random number generation units 14A and 14B.

  Further, according to the semiconductor storage devices 2A and 2B and the data processing system 100 according to the first and second embodiments, the random number generation data is prohibited from being accessed from the host device 1 in the storage area of the memory array 17. The prohibited area 20 is stored. Accordingly, the attacker cannot read out the random number generation data from the memory array 17 via the host device 1 or overwrite the random number generation data stored in the memory array 17 with invalid data. Can be improved.

  Further, according to the semiconductor memory devices 2A and 2B according to the above-described modification, when the semiconductor memory devices 2A and 2B are powered on, the data updating unit 15A and 15B update the random number generating data and the control unit 13 The random number generation data is overwritten automatically. Therefore, in the first random number generation after the power is turned on, it is possible to generate a random number based on the new random number generation data overwritten by the automatic update.

  Similarly, according to the data processing system 100 according to the modified example, when the semiconductor memory devices 2A and 2B are powered on, the data update unit 15A and 15B update the random number generation data and the control unit 13 generates the random number. The data overwriting process is automatically executed. Therefore, for the first key request after power-on, a session key generated based on new random number generation data overwritten by automatic updating can be transmitted to the host device 1.

  In addition, according to the semiconductor memory devices 2A and 2B according to the above modification, when the semiconductor memory devices 2A and 2B are requested to be powered off, the data updating unit 15A and 15B update the random number generating data and the control unit 13 The random number generation data overwriting process is automatically executed. Therefore, in the first random number generation after the power of the semiconductor memory devices 2A and 2B is turned on again, it is possible to generate a random number based on the new random number generation data overwritten by the automatic update before power-off. It becomes.

  Similarly, according to the data processing system 100 according to the above modification, when the semiconductor memory devices 2A and 2B are requested to be turned off, the data updating unit 15A and 15B updates the random number generation data and the control unit 13 generates the random number. The generation data overwrite process is automatically executed. Therefore, for the first key request after the power of the semiconductor memory devices 2A and 2B is turned on again, the session key generated based on the new random number generation data overwritten by the automatic update before the power is turned off. Can be transmitted to the host device 1.

2, 2A, 2B Semiconductor memory device 13 Control unit 14A Random number generation unit 15A, 15B Data update unit 17 Memory array 20 Forbidden area 21, 23 Random number generator 22 Counter 100 Data processing system

Claims (15)

A memory array in which random number generation data used for random number generation is stored;
A random number generation unit that generates random numbers by a predetermined random number generation algorithm using the random number generation data read from the memory array as a seed,
A data update unit for updating the random number generation data;
A control unit;
A semiconductor memory device Ru provided with,
The data updating unit updates the first random number generation data read from the memory array with an algorithm different from the random number generation algorithm, thereby generating the first random number generation data based on the first random number generation data. Generating second random number generation data for generating a second random number used after the random number of 1,
The control unit writes the second random number generation data to the memory array,
The random number generation process by the random number generation unit, the random number generation data update process by the data update unit and the random number generation data write process by the control unit are executed in parallel ,
When the semiconductor memory device is requested to be powered off, the random number generation data update process by the data update unit and the random number generation data write process by the control unit are automatically executed .   The semiconductor memory device according to claim 1, wherein the data updating unit generates the second random number generation data different from the first random number generation data.   3. The semiconductor memory device according to claim 1, wherein the control unit repeatedly executes a random number generation data writing process until the second random number generation data is correctly written in the memory array.   The semiconductor memory device according to claim 1, wherein a unique value that differs for each semiconductor memory device is stored in the memory array as an initial value of random number generation data.   5. The semiconductor memory device according to claim 1, wherein the random number generation data is stored in an area where access from a host device is prohibited in the memory area of the memory array.   6. The random number generation data update process by the data update unit and the random number generation data write process by the control unit are automatically executed when the semiconductor memory device is powered on. The semiconductor memory device according to any one of the above.   A host device;
  A semiconductor memory device that decrypts a command received from the host device by exchanging a key with the host device, and encrypts data to be transmitted to the host device by using the key ,
With
  The semiconductor memory device
  A memory array that stores data to be transmitted to and received from the host device, and key generation data used to generate a key;
  A key generation unit that generates a key to be transmitted to the host device in response to the current key request by generating a random number by a predetermined random number generation algorithm using the key generation data read from the memory array as a seed When,
  A data update unit for updating key generation data;
  A control unit;
Have
  When the semiconductor storage device receives a key request from the host device,
  The key generation unit generates a key to be transmitted to the host device in response to the current key request based on the first key generation data stored in the memory array at that time,
  The control unit encrypts the key generated by the key generation unit and transmits the encrypted key to the host device,
  The data updating unit updates the first key generation data with an algorithm different from the random number generation algorithm, thereby generating a key to be transmitted to the host device in response to a key request after this time. Generating second key generation data for
  The control unit writes the second key generation data to the memory array,
  The key generation process by the key generation unit and the key transmission process by the control unit, the key generation data update process by the data update unit, and the key generation data write process by the control unit are performed in parallel. A data processing system to be executed.   The data processing system according to claim 7, wherein the data update unit generates the second key generation data different from the first key generation data.   9. The data processing system according to claim 7, wherein the control unit repeatedly executes a key generation data writing process until the second key generation data is correctly written in the memory array.   The data processing system according to claim 7, wherein a unique value that differs for each semiconductor memory device is stored in the memory array as an initial value of key generation data.   The data processing system according to any one of claims 7 to 10, wherein the key generation data is stored in an area where access from the host device is prohibited in the storage area of the memory array.   12. The key generation data update process by the data update unit and the key generation data write process by the control unit are automatically executed when the semiconductor memory device is powered on. A data processing system according to any one of the above.   The process for updating key generation data by the data update unit and the process for writing key generation data by the control unit are automatically executed when the semiconductor memory device is requested to be powered off. The data processing system according to any one of 12.   A memory array in which key generation data used for key generation is stored;
  A key generation unit that generates a key by generating random numbers by a predetermined random number generation algorithm using the key generation data read from the memory array as a seed; and
  A data update unit for updating key generation data;
  A control unit;
With
  The key generation unit generates a first key based on first key generation data stored in the memory array,
  The data update unit updates the first key generation data by an algorithm different from the random number generation algorithm, thereby generating a second key for generating a second key used after the first key. Generate key generation data for
  The control unit writes the second key generation data to the memory array,
  The semiconductor memory device, wherein the key generation process by the key generation unit, the key generation data update process by the data update unit, and the key generation data write process by the control unit are executed in parallel.   The semiconductor memory device according to claim 14, wherein the data update unit generates the second key generation data different from the first key generation data.

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