JP6069120B2 - Information processing system - Google Patents

Description

  The present invention relates to an information processing system including a communication device and a storage device.

  In an information processing system including a communication device and a semiconductor storage device connected thereto, in order to prevent content data stored in the semiconductor storage device from being read illegally, before permitting access to the content data, A technology (mutual authentication technology) in which a communication device and a semiconductor storage device mutually authenticate each other has been put into practical use.

  In general challenge-and-response mutual authentication, the communication device issues an authentication command for instructing execution of mutual authentication. The communication device generates a first authentication code based on the authentication command, encrypts the first authentication code, and transmits the encrypted first authentication code to the semiconductor memory device. After decrypting the received first authentication code, the semiconductor storage device encrypts the first authentication code again and transmits it to the communication device. The communication device decrypts the received first authentication code and then determines whether the first authentication code transmitted to the semiconductor memory device matches the first authentication code received from the semiconductor memory device. Authenticate the validity of the storage device. Further, after the communication device authenticates the validity of the semiconductor storage device, the semiconductor storage device generates a second authentication code, encrypts the second authentication code, and transmits it to the communication device. After decrypting the received second authentication code, the communication device encrypts the second authentication code again and transmits it to the semiconductor memory device. The semiconductor memory device determines whether the second authentication code transmitted to the communication device after decrypting the received second authentication code matches the second authentication code received from the communication device. Authenticate the validity of When the validity of the communication device and the semiconductor storage device is mutually authenticated by the above processing, the communication device issues an access command for accessing the content data.

  In Patent Document 1 below, a plurality of mutual authentication procedures are prepared, and the CPU selects one mutual authentication procedure from among the plurality of mutual authentication procedures. An information processing apparatus to be executed is disclosed.

JP 2000-349751

  According to the general challenge-and-response mutual authentication described above, an authentication command is issued before the access command is issued, and the first authentication code is transmitted from the communication device to the semiconductor memory device based on the authentication command. And the reception of the response value, the transmission of the second authentication code from the semiconductor memory device to the communication device, and the reception of the response value are sequentially performed. An access command is issued when the authenticity of the communication device and the semiconductor memory device is mutually authenticated. Accordingly, since the overhead associated with the mutual authentication process is large, the time required to access the content data becomes long.

  The present invention has been made in view of such circumstances, and an information processing system capable of shortening the time required to access content data by reducing the overhead associated with authentication processing is obtained. It is intended.

  An information processing system according to a first aspect of the present invention is an information processing system comprising: a communication device; and a storage device connected to the communication device and having a storage unit in which content data is stored. An apparatus generates an access command with an authentication code by adding a first authentication code for causing the storage device to authenticate the communication device to an access command for accessing the storage unit, and the authentication code To the storage device, the storage device receives the access command with the authentication code from the communication device, and based on the first authentication code included in the access command with the authentication code, If the communication device is authenticated and the communication device is determined to be valid, it is included in the access command with the authentication code. Based on said access command, and is characterized in that access to the storage unit.

  According to the information processing system according to the first aspect, the communication device generates an access command with an authentication code by adding the first authentication code to the access command, and transmits the access command with the authentication code to the storage device. To do. Further, the storage device receives the access command with an authentication code from the communication device, and authenticates the communication device based on the first authentication code included in the access command with the authentication code. When it is determined that the communication device is valid, the storage unit is accessed based on the access command included in the access command with the authentication code. As described above, by using the access command with an authentication code in which the first authentication code is added to the access command, the authentication of the communication device by the storage device and the access to the storage unit can be executed as a common process. it can. As a result, it is not necessary for the storage device to separately authenticate the communication device before the communication device transmits an access command to the storage device, and the overhead associated with the authentication processing can be reduced, so that content data can be accessed. It is possible to shorten the time required to do.

  In the information processing system according to the second aspect of the present invention, in particular in the information processing system according to the first aspect, the storage device further responds to the access command when the communication device determines that the communication device is valid. Generating a content data with an authentication code by adding a second authentication code for causing the communication device to authenticate the storage device to the content data to be transmitted to the communication device. Transmitting to the communication device, the communication device receives the content data with the authentication code from the storage device, and authenticates the storage device based on the second authentication code included in the content data with the authentication code It is characterized by doing.

  According to the information processing system according to the second aspect, the storage device generates content data with an authentication code by adding the second authentication code to the content data, and transmits the content data with the authentication code to the communication device. To do. Then, the communication device receives the content data with the authentication code from the storage device, and authenticates the storage device based on the second authentication code included in the content data with the authentication code. Thus, by using content data with an authentication code in which a second authentication code is added to content data, transmission of content data from the storage device to the communication device and authentication of the storage device by the communication device are common. It can be executed as a process. As a result, it is not necessary for the communication device to separately authenticate the storage device before the storage device transmits the content data to the communication device, and the overhead associated with the authentication process can be reduced, thereby accessing the content data. It is possible to shorten the time required to do.

  In addition, the communication device and the storage device can communicate with each other by one-way communication between the transmission of the access command with the authentication code from the communication device to the storage device and the transmission of the content data with the authentication code from the storage device to the communication device in response. Mutual authentication can be performed. As a result, compared to general challenge and response mutual authentication that requires two-way communication (two-way communication in total) from each of the communication device and the storage device, the processing speed and efficiency can be improved. It becomes possible.

  An information processing system according to a third aspect of the present invention is the information processing system according to the second aspect, in particular, the communication device includes a main control unit that controls the information processing system by software processing, and the main control unit And a first control circuit that controls the storage device by hardware processing, and the storage device further includes a second control circuit that controls the storage unit, and the access Issuing a command is executed by the main control unit, and generation and transmission of the access command with the authentication code, reception of the content data with the authentication code, and authentication of the storage device based on the second authentication code Executed by the first control circuit, receiving the access command with the authentication code, authenticating the communication device based on the first authentication code, and the authentication. The generation and transmission of coded content data, is characterized in that said second control circuit is performed.

  According to the information processing system according to the third aspect, the generation and transmission of the access command with the authentication code, the reception of the content data with the authentication code, and the authentication of the storage device based on the second authentication code are the first The control circuit executes. The second control circuit executes reception of an access command with an authentication code, authentication of a communication device based on the first authentication code, and generation and transmission of content data with an authentication code. As described above, in the mutual authentication between the communication device and the storage device, the processing executed by the main control unit is only the issuance of the access command. Based on the generation of the access command with the authentication code and the content data with the authentication code, Essential processing such as authentication is executed between the first control circuit and the second control circuit. Therefore, even when an attack that modifies the control of the main control unit by program analysis or the like is performed, unless the contents of the hardware processing by the first control circuit and the second control circuit are analyzed and modified, The attacker cannot avoid the mutual authentication process. As a result, it is possible to prevent content data from being illegally read from the storage device even in the case of an attack that alters the control of the main control unit.

  In the information processing system according to the fourth aspect of the present invention, in particular in the information processing system according to the third aspect, when the second control circuit determines that the communication device is illegal, Access to the storage unit based on is not performed.

  According to the information processing system according to the fourth aspect, when the second control circuit determines that the communication device is illegal, the second control circuit does not access the storage unit based on the access command. Accordingly, even when a read command is transmitted from the unauthorized communication device to the storage device, the second control circuit does not read the content data from the storage unit. As a result, it is possible to prevent content data from being illegally read from the storage device.

  The information processing system according to the fifth aspect of the present invention is the information processing system according to the fourth aspect, particularly when the second control circuit further determines that the communication device is illegal. The access command transmitted from the first control circuit is not received.

  According to the information processing system according to the fifth aspect, when the second control circuit determines that the communication device is illegal, the second control circuit does not receive an access command transmitted from the first control circuit thereafter. Therefore, even when a read command is transmitted from an unauthorized communication device to the storage device, the second control circuit does not receive the read command. As a result, it is possible to prevent content data from being illegally read from the storage device.

  An information processing system according to a sixth aspect of the present invention is the information processing system according to any one of the third to fifth aspects, and in particular, the first control circuit is included in the content data with an authentication code. When content data is input to the main control unit and it is determined that the storage device is illegal, a notification that the storage device is illegal is input to the main control unit.

  According to the information processing system of the sixth aspect, the first control circuit uses the content data included in the content data with the authentication code as the main control unit regardless of whether the storage device is valid or illegal. input. Accordingly, it is possible to input the received content data to the main control unit at an early stage without waiting for the completion of the process for authenticating the storage device. Further, when the first control circuit determines that the storage device is illegal, the first control circuit inputs a notification that the storage device is illegal to the main control unit. Therefore, the main control unit can execute processing such as discarding or invalidating the content data input from the first control circuit.

  An information processing system according to a seventh aspect of the present invention is the information processing system according to any one of the third to fifth aspects, particularly when the first control circuit determines that the storage device is illegal. Is characterized in that the content data included in the content data with the authentication code is not input to the main control unit.

  According to the information processing system according to the seventh aspect, when the first control circuit determines that the storage device is illegal, the first control circuit does not input the content data included in the content data with the authentication code to the main control unit. Accordingly, it is possible to prevent content data read from an unauthorized storage device from being input to the main control unit.

  In the information processing system according to the eighth aspect of the present invention, particularly in the information processing system according to the sixth or seventh aspect, when the first control circuit further determines that the storage device is illegal, The subsequent communication between the first control circuit and the second control circuit is cut off.

  According to the information processing system according to the eighth aspect, when the first control circuit determines that the storage device is illegal, subsequent communication between the first control circuit and the second control circuit is performed. Shut off. Therefore, it is possible to avoid the access command being transmitted from the communication device to the unauthorized storage device, the content data being transmitted from the unauthorized storage device to the communication device, and the like. As a result, it is possible to prevent content data from being illegally read from the storage device.

  An information processing system according to a ninth aspect of the present invention is the information processing system according to any one of the third to eighth aspects, in which the first control circuit generates a first number sequence. And a first authentication control unit that generates the first authentication code based on the first number sequence, wherein the second control circuit is the same as the first number sequence. A second number sequence generation unit that generates a second number sequence; and a second authentication control unit that generates the second authentication code based on the second number sequence, the second authentication control unit Authenticates the communication device depending on whether the first authentication code included in the access command with the authentication code matches the second authentication code generated based on the second number sequence. The first authentication control unit is included in the data with the authentication code. Said second authentication code to be, depending on whether said first of said first authentication code generated based on the sequence match, it is characterized in authenticating the storage device.

  According to the information processing system according to the ninth aspect, the second authentication control unit includes the first authentication code included in the access command with the authentication code and the second authentication code generated based on the second number sequence. The communication device is authenticated depending on whether or not matches. If the communication device is illegal, the first authentication code included in the access command with the authentication code does not match the second authentication code generated based on the second number sequence. Therefore, it is possible to reliably detect that the communication device is illegal. Further, the first authentication control unit determines whether the second authentication code included in the content data with the authentication code matches the first authentication code generated based on the first number sequence. Authenticate. If the storage device is illegal, the second authentication code included in the content data with the authentication code does not match the first authentication code generated based on the first number sequence. Therefore, it is possible to reliably detect that the storage device is illegal.

  The information processing system according to a tenth aspect of the present invention is the information processing system according to the ninth aspect, in particular, the first authentication control unit compresses the first number sequence to compress the first number sequence. An authentication code is generated, and the second authentication control unit generates the second authentication code by compressing the second number sequence.

  According to the information processing system according to the tenth aspect, the first authentication control unit generates the first authentication code by compressing the first number sequence, and the second authentication control unit A second authentication code is generated by compressing the sequence. Therefore, even when the bit lengths of the first number sequence and the second number sequence exceed the allowable authentication code length, the first number sequence and the second number sequence are compressed into the allowable authentication code length by compressing the first number sequence and the second number sequence. One authentication code and second authentication code can be generated.

  An information processing system according to an eleventh aspect of the present invention is the information processing system according to the ninth or tenth aspect, in which the first number sequence generation unit and the second number sequence generation unit are each authenticated. The first number sequence and the second number sequence different from each other are generated respectively.

  According to the information processing system according to the eleventh aspect, the first number sequence generation unit and the second number sequence generation unit generate a first number sequence and a second number sequence that are different for each authentication process. As a result, since the first authentication code and the second authentication code are changed for each authentication process, the security strength can be improved.

  An information processing system according to a twelfth aspect of the present invention is transmitted from the first control circuit to the second control circuit, particularly in the information processing system according to any one of the ninth to eleventh aspects. The first authentication code included in the access command with the authentication code and the content data with the authentication code transmitted from the second control circuit to the first control circuit in response to the access command The second authentication code is different from each other.

  According to the information processing system of the twelfth aspect, in response to the first authentication code included in the access command with the authentication code transmitted from the first control circuit to the second control circuit, and the access command. The second authentication code is different from the second authentication code included in the content data with the authentication code transmitted from the second control circuit to the first control circuit. That is, the first authentication code that the communication device transmits to the storage device and the second authentication code that the communication device receives from the storage device are different from each other. In this way, it is possible to improve the security strength by making the authentication code different between transmission and reception.

  The information processing system according to a thirteenth aspect of the present invention is the information processing system according to the twelfth aspect, in particular, the second number sequence used when the second authentication control unit authenticates the communication device. The second authentication code is generated based on the updated second number sequence generated next, and the first authentication control unit generates the second authentication code and the first authentication code. Depending on whether or not the updated first authentication code generated based on the updated first number sequence generated next to the first number sequence used at the time of generation matches the storage device, It is characterized by authenticating.

  According to the information processing system according to the thirteenth aspect, the second authentication control unit is based on the updated second number sequence generated next to the second number sequence used when authenticating the communication device. A second authentication code is generated. Accordingly, the second authentication code transmitted from the storage device to the communication device can be easily and reliably changed from the first authentication code transmitted from the communication device to the storage device. In addition, the first authentication control unit includes the updated second authentication code generated based on the updated second number sequence and the updated first number generated based on the updated first number sequence. The storage device is authenticated depending on whether the authentication code matches. If the storage device is valid, the updated second authentication code matches the updated first authentication code, while if the storage device is incorrect, the updated second authentication code. This authentication code does not match the updated first authentication code. Therefore, it is possible to easily and reliably determine whether the storage device is valid or not by checking whether the updated second authentication code matches the updated first authentication code. Is possible.

  According to the present invention, it is possible to reduce the time required to access content data by reducing the overhead associated with the authentication process.

1 is a diagram schematically showing an overall configuration of an information processing system according to an embodiment of the present invention. It is a figure which shows the structure of a microprocessor. It is a figure which shows the structure of a memory controller. It is a figure which shows the structure of a memory controller. It is a figure which shows a read command. It is a figure which shows the read command with an authentication code. It is a figure which shows the 1st example of content data with an authentication code. It is a figure which shows the 2nd example of content data with an authentication code.

  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 an overall configuration of an information processing system 1 according to an embodiment of the present invention. The information processing system 1 includes a communication device 2 and a semiconductor storage device 3. The communication device 2 is a personal computer, for example. The semiconductor memory device 3 is, for example, a memory card that can be detachably connected to the communication device 2. Alternatively, an arbitrary storage device such as an optical disk or a magnetic disk can be used in place of the semiconductor storage device 3.

  The communication device 2 includes a microprocessor 11 (main control unit) as a main system that controls the information processing system 1 by software processing, and a memory controller 12 (first control circuit) mounted separately from the microprocessor 11. It is prepared for. The memory controller 12 controls the semiconductor memory device 3 by hardware processing.

  The semiconductor storage device 3 includes a memory array 22 (storage unit) that stores arbitrary content data such as images, sounds, texts, codes, management information, and the like, and a memory controller 21 (second control circuit) that controls the memory array 22 ). The memory array 22 is configured using, for example, a NAND flash memory. However, the present invention is not limited to this example, and the memory array 22 may be configured using a NOR flash memory or the like.

  FIG. 2 is a diagram showing the configuration of the microprocessor 11. The microprocessor 11 includes a CPU 41, a computing unit 42, a RAM 43, a ROM 44, a bridge 45, and a register 46 that are connected to each other via a bus 47.

  FIG. 3 is a diagram illustrating a configuration of the memory controller 12. As shown in the connection relationship in FIG. 3, the memory controller 12 includes a key generation unit 51 (first number sequence generation unit), an encryption / decryption unit 52, an authentication control unit 53 (first authentication control unit), and a mask. Circuits 54 and 55 are provided. The key generation unit 51 generates a random number sequence (session key K in the following example) by using a predetermined random number generation algorithm using a fixed secret key P with high confidentiality. The key generation unit 51 generates a different session key K (nonce) every time the memory controller 12 receives an access command from the microprocessor 11.

  FIG. 4 is a diagram illustrating the configuration of the memory controller 21. As shown in the connection relationship of FIG. 4, the memory controller 21 includes a key generation unit 61 (second number sequence generation unit), an encryption / decryption unit 62, and an authentication control unit 63 (second authentication control unit). Configured. The key generation unit 61 uses the same shared key P as the shared key P held by the key generation unit 51, and uses the same random number generation algorithm as the key generation unit 51 to generate the session key K generated by the key generation unit 51. The same session key K is generated. The key generation unit 61 generates a different session key K every time the memory controller 21 receives an access command with an encrypted authentication code from the memory controller 12.

  Hereinafter, the operation of the information processing system 1 according to the present embodiment will be described with reference to FIGS. As a premise, it is assumed that the encryption / decryption units 52 and 62 are initialized with the session key K (N−1) generated last time by the key generation units 51 and 61. In the following example, a case where a read command is used as an access command for the communication device 2 to access the memory array 22 will be described.

  First, the microprocessor 11 issues a read command C0 having a predetermined byte length for reading desired content data from the memory array 22. FIG. 5 is a diagram showing the read command C0. The read command C0 has a specific command ID for identifying that it is a read command, an address indicating the storage location of content data in the memory array 22, and an undefined area filled with meaningless data. including.

  Referring to FIG. 3, the memory controller 12 receives a read command C0 from the microprocessor 11 and inputs the received read command C0 to the authentication control unit 53.

  Next, the key generation unit 51 generates a session key K (N) according to a request from the authentication control unit 53. The session key K (N) is input to the encryption / decryption unit 52 and the authentication control unit 53.

  Next, the authentication control unit 53 generates an authentication code S (N) for the semiconductor storage device 3 to authenticate the validity of the communication device 2 based on the session key K (N). For example, when the bit length of the session key K (N) is less than or equal to a predetermined allowable authentication code length, the session key K (N) is used as it is as the authentication code S (N). On the other hand, when the bit length of the session key K (N) exceeds the allowable authentication code length, an authentication code S (N) that fits within the allowable authentication code length is generated by compressing the session key K (N). As an example, when the allowable authentication code length is set to the bit length (for example, 32 bits) of the undefined area of the read command C0, and the bit length of the session key K (N) is 128 bits, the session key K (N) is divided into four bit groups of 127-96 bits, 95-64 bits, 63-32 bits, and 31-0 bits, and the next bit group in order from the first bit group. Exclusive OR operation between them ([127: 96] ExOR [95:64] ExOR [63:32] ExOR [31: 0]). As a result, a 32-bit authentication code S (N) is generated from the 128-bit session key K (N).

  Next, the authentication control unit 53 generates the read command C1 (N) with an authentication code by adding the authentication code S (N) to the read command C0. FIG. 6 shows the read command C1 (N) with an authentication code. The authentication control unit 53 replaces meaningless data included in the undefined area of the read command C0 with the authentication code S (N), thereby adding an authentication code including a command ID, an address, and an authentication code S (N). A read command C1 (N) is generated. The authentication control unit 53 inputs the generated read command with authentication code C1 (N) to the encryption / decryption unit 52.

  Next, the encryption / decryption unit 52 encrypts the read command with authentication code C1 (N) using the currently set session key K (N-1), thereby reading the read command with encrypted authentication code. X (N) is generated. Then, the generated read command with encrypted authentication code X (N) is transmitted to the memory controller 21.

  Next, the authentication control unit 53 initializes the encryption / decryption unit 52 with the session key K (N) generated by the key generation unit 51 this time.

  The memory controller 21 inputs the encrypted read command with authentication code X (N) received from the memory controller 12 to the encryption / decryption unit 62.

  Next, the encryption / decryption unit 62 decrypts the encrypted read command with authentication code X (N) using the currently set session key K (N-1), thereby reading the read command with authentication code C1. Play (N). Then, the reproduced read command with authentication code C1 (N) is input to the authentication control unit 63.

  Next, the authentication control unit 63 extracts the read command C0 and the authentication code S (N) from the read command with authentication code C1 (N).

  Next, the key generation unit 61 generates a session key K (N) according to a request from the authentication control unit 63. The session key K (N) is input to the encryption / decryption unit 62 and the authentication control unit 63. Next, the authentication control unit 63 generates an authentication code S (N) based on the session key K (N) by the same process as the authentication control unit 53 described above.

  Next, the authentication control unit 63 generates an authentication code S (N) extracted from the read command with authentication code C1 (N) and an authentication code S generated based on the session key K (N) input from the key generation unit 61. By comparing (N), the authenticity of the communication device 2 is authenticated. Specifically, when both authentication codes S (N) match, the communication device 2 is determined to be valid, and when both authentication codes S (N) do not match, the communication device 2 is determined to be illegal.

  If the authentication control unit 63 determines that the communication device 2 is illegal, the authentication control unit 63 does not access the memory array 22 based on the read command C0 extracted from the read command C1 (N) with the authentication code. That is, reading of content data from the memory array 22 is not executed.

  If the authentication control unit 63 determines that the communication device 2 is illegal, the authentication control unit 63 prohibits the encryption / decryption unit 62 from receiving transmission data from the communication device 2. Thereby, the memory controller 21 does not receive an access command transmitted from the communication device 2 to the semiconductor memory device 3 thereafter.

  On the other hand, when it is determined that the communication device 2 is valid, the authentication control unit 63 next accesses the memory array 22 based on the read command C0 extracted from the read command with authentication code C1 (N). That is, the content data T0 is read from the memory array 22 by the control signal U indicating the read address.

  If the authentication control unit 63 determines that the communication device 2 is valid, the authentication control unit 63 initializes the encryption / decryption unit 62 with the session key K (N) generated by the key generation unit 61 this time.

  Next, the key generation unit 61 generates the next session key K (N + 1) according to the request from the authentication control unit 63. Session key K (N + 1) is input to authentication control unit 63.

  Next, the authentication control unit 63 generates an authentication code S (N + 1) based on the session key K (N + 1) input from the key generation unit 61. Similar to the authentication control unit 53 described above, the authentication control unit 63 uses the session key K (N + 1) as it is when the bit length of the session key K (N + 1) is equal to or less than a predetermined allowable authentication code length. Used as (N + 1). On the other hand, when the bit length of the session key K (N + 1) exceeds the allowable authentication code length, the session key K (N + 1) is compressed to generate an authentication code S (N + 1) that fits within the allowable authentication code length.

  Next, the authentication control unit 63 generates content data T1 (N + 1) with an authentication code by adding an authentication code S (N + 1) to the content data T0. FIG. 7 is a diagram showing a first example of content data T1 (N + 1) with an authentication code. The authentication control unit 63 generates content data T1 (N + 1) with an authentication code by adding an authentication code S (N + 1) to the end of the content data T0. FIG. 8 is a diagram illustrating a second example of content data T1 (N + 1) with an authentication code. The authentication control unit 63 generates content data T1 (N + 1) with an authentication code by adding an authentication code S (N + 1) to the head of the content data T0. The authentication control unit 63 inputs the generated content data T1 (N + 1) with an authentication code to the encryption / decryption unit 62.

  Next, the encryption / decryption unit 62 encrypts the content data T1 (N + 1) with the authentication code by using the session key K (N) that is currently set, so that the encrypted content data Y (with the authentication code Y ( N + 1). Then, the generated content data Y (N + 1) with an encrypted authentication code is transmitted to the memory controller 12.

  The memory controller 12 inputs the encrypted authentication code-added content data Y (N + 1) received from the memory controller 21 to the encryption / decryption unit 52.

  Next, the encryption / decryption unit 52 decrypts the encrypted authentication code-added content data Y (N + 1) using the currently set session key K (N), thereby providing the authentication code-added content data T1 (N + 1). ). Then, the reproduced content data T 1 (N + 1) with an authentication code is input to the authentication control unit 53.

  Next, the authentication control unit 53 extracts the content data T0 and the authentication code S (N + 1) from the content data T1 (N + 1) with an authentication code.

  Next, the key generation unit 51 generates a session key K (N + 1) according to the request from the authentication control unit 53. Session key K (N + 1) is input to authentication control unit 53. Next, the authentication control unit 53 generates an authentication code S (N + 1) based on the session key K (N + 1) by the same processing as the authentication control unit 63 described above.

  Next, the authentication control unit 53 generates the authentication code S (N + 1) extracted from the content data T1 (N + 1) with the authentication code and the authentication code S generated based on the session key K (N + 1) input from the key generation unit 61. The validity of the semiconductor memory device 3 is authenticated by comparing (N + 1). Specifically, when both authentication codes S (N + 1) match, the semiconductor memory device 3 is determined to be valid, and when both authentication codes S (N + 1) do not match, the semiconductor memory device 3 is determined to be illegal. .

  According to the first example shown in FIG. 7, the authentication code S (N + 1) is added to the end of the content data T0. Accordingly, the authentication control unit 53 processes the content data T0 before the authentication code S (N + 1). In this case, the authentication control unit 53 inputs the content data T0 extracted from the content data T1 (N + 1) with the authentication code to the microprocessor 11 without waiting for the completion of the process of authenticating the validity of the semiconductor memory device 3. Thereafter, when it is determined by authentication that the semiconductor memory device 3 is illegal, the authentication control unit 53 inputs a notification to the microprocessor 11 that the semiconductor memory device 3 is illegal. On the other hand, when it is determined that the semiconductor memory device 3 is valid, the authentication control unit 53 does not input a notification to the microprocessor 11 that the semiconductor memory device 3 is illegal.

  According to the second example shown in FIG. 8, the authentication code S (N + 1) is added to the head of the content data T0. Accordingly, the authentication control unit 53 processes the authentication code S (N + 1) before the content data T0. In this case, the authentication control unit 53 first performs the process of authenticating the validity of the semiconductor storage device 3. If the authentication determines that the semiconductor storage device 3 is unauthorized, the content data T1 (N + 1) with an authentication code is used. The extracted content data T0 is not input to the microprocessor 11. On the other hand, when it is determined that the semiconductor memory device 3 is valid, the authentication control unit 53 inputs the content data T0 extracted from the content data T1 (N + 1) with authentication code to the microprocessor 11.

  Further, when the authentication control unit 53 determines that the semiconductor memory device 3 is illegal, the authentication control unit 53 sends a control signal D for enabling a mask process such as replacing data to all “0” or all “1” to the mask circuit. 54 and 55. Thereby, subsequent communication between the communication device 2 and the semiconductor memory device 3 is blocked.

  Each time the read command is issued from the microprocessor 11, the authentication control units 53 and 63 perform the mutual authentication process similar to the above. In the next mutual authentication process, the authentication control unit 63 is based on the authentication code S (N + 1) extracted from the read command with authentication code C1 (N + 1) and the session key K (N + 1) input from the key generation unit 61. The authenticity of the communication device 2 is authenticated depending on whether or not the generated authentication code S (N + 1) matches. The authentication control unit 53 also generates an authentication code S generated based on the authentication code S (N + 2) extracted from the content data T1 (N + 2) with the authentication code and the session key K (N + 2) input from the key generation unit 51. The validity of the semiconductor memory device 3 is authenticated depending on whether (N + 2) matches.

<First Modification>
In the above description, the process in which the communication device 2 authenticates the validity of the semiconductor storage device 3 is executed by the hardware process of the memory controller 12, but may be executed by the software process of the microprocessor 11.

<Second Modification>
In the above description, the authentication code S is added to the read command C0 and the content data T0 as its response value. However, the authentication code S may be added to other access commands such as a write command and an erase command.

  When the authentication code S is added to the write command, the semiconductor memory device 3 uses the authentication code S added to the write command received from the communication device 2 and the authentication code S generated by itself to the communication device. 2 can be authenticated. Further, by adding the authentication code S to the status notification as the response value of the status command transmitted following the write command, the communication device 2 can authenticate the status code received from the semiconductor memory device 3. The validity of the semiconductor memory device 3 can be authenticated based on S and the authentication code S generated by itself.

  When the authentication code S is added to the erase command, the semiconductor memory device 3 determines the communication device based on the authentication code S added to the erase command received from the communication device 2 and the authentication code S generated by itself. 2 can be authenticated. Further, by adding the authentication code S to the status notification as the response value of the status command transmitted following the erase command, the communication device 2 can add the authentication code added to the status notification received from the semiconductor memory device 3. The validity of the semiconductor memory device 3 can be authenticated based on S and the authentication code S generated by itself.

<Summary>
According to the information processing system 1 according to the present embodiment, the communication device 2 generates the read command C1 (N) with the authentication code by adding the first authentication code S (N) to the read command C0, The read command with authentication code C1 (N) is transmitted to the semiconductor memory device 3. Further, the semiconductor memory device 3 receives the read command C1 (N) with an authentication code from the communication device 2, and based on the authentication code S (N) included in the read command with authentication code C1 (N), the communication device 2 is authenticated. When it is determined that the communication device 2 is valid, the memory array 22 is accessed based on the read command C0 included in the read command with authentication code C1 (N). Thus, by using the read command C1 (N) with an authentication code in which the authentication code S (N) is added to the read command C0, the authentication of the communication device 2 by the semiconductor memory device 3 and the access to the memory array 22 Can be executed as a common process. As a result, before the communication device 2 transmits a read command to the semiconductor storage device 3, the semiconductor storage device 3 does not need to separately execute a process for authenticating the communication device 2, and overhead associated with the authentication process can be reduced. Therefore, the time required to access the content data T0 can be shortened.

  Further, according to the information processing system 1 according to the present embodiment, the semiconductor storage device 3 adds the content data T1 (N + 1) with the authentication code by adding the second authentication code S (N + 1) to the content data T0. The authentication code-added content data T1 (N + 1) is generated and transmitted to the communication device 2. Then, the communication device 2 receives the content data T1 (N + 1) with the authentication code from the semiconductor storage device 3, and based on the authentication code S (N + 1) included in the content data T1 (N + 1) with the authentication code The device 3 is authenticated. As described above, by using the content data T1 (N + 1) with the authentication code obtained by adding the authentication code S (N + 1) to the content data T0, the transmission of the content data T0 from the semiconductor storage device 3 to the communication device 2, and the communication device 2 can be executed as a common process. As a result, it is not necessary for the communication device 2 to separately authenticate the semiconductor memory device 3 before the semiconductor memory device 3 transmits the content data to the communication device 2, and overhead associated with the authentication processing can be reduced. Therefore, the time required to access the content data T0 can be shortened.

  In addition, transmission of the read command C1 (N) with an authentication code from the communication device 2 to the semiconductor storage device 3, and transmission of content data T1 (N + 1) with an authentication code from the semiconductor storage device 3 to the communication device 2 in response thereto Thus, mutual authentication between the communication device 2 and the semiconductor memory device 3 can be performed by one-way communication. As a result, compared to general challenge and response mutual authentication that requires two-way communication (two-way communication in total) from each of the communication device and the semiconductor memory device, the processing speed and efficiency are improved. Is possible.

  Further, according to the information processing system 1 according to the present embodiment, the generation and transmission of the read command C1 (N) with the authentication code, the reception of the content data T1 (N + 1) with the authentication code, and the authentication code S (N + 1) The memory controller 12 executes authentication of the semiconductor memory device 3 based on the above. The memory controller 21 receives the read command C1 (N) with the authentication code, authenticates the communication device 2 based on the authentication code S (N), and generates and transmits the content data T1 (N + 1) with the authentication code. Run. Thus, in the mutual authentication between the communication device 2 and the semiconductor memory device 3, the processing executed by the microprocessor 11 is only the issue of the read command C0, and the read command C1 (N) with the authentication code and the content data with the authentication code. Essential processing such as generation of T1 (N + 1) and authentication based on the authentication codes S (N) and S (N + 1) is executed between the memory controller 12 and the memory controller 21. Accordingly, even when an attack that alters the control of the microprocessor 11 by program analysis or the like is performed, the attacker can interact with each other as long as the contents of the hardware processing by the memory controller 12 and the memory controller 21 are not analyzed and altered. Authentication processing is not avoided. As a result, it is possible to prevent unauthorized reading of the content data T0 from the semiconductor storage device 3 even when an attack that alters the control of the microprocessor 11 is received.

  Also, according to the information processing system 1 according to the present embodiment, the memory controller 21 does not access the memory array 22 based on the read command C0 when the communication device 2 is determined to be illegal. Accordingly, even when a read command is transmitted from the unauthorized communication device 2 to the semiconductor memory device 3, the memory controller 21 does not read the content data T0 from the memory array 22. As a result, it is possible to prevent content data T0 from being read from the semiconductor memory device 3 illegally.

  Further, according to the information processing system 1 according to the present embodiment, the memory controller 21 does not receive an access command transmitted from the memory controller 12 after that when the communication device 2 is determined to be illegal. Accordingly, even when a read command is transmitted from the unauthorized communication device 2 to the semiconductor memory device 3, the memory controller 21 does not receive the read command. As a result, it is possible to prevent content data T0 from being read from the semiconductor memory device 3 illegally.

  In the information processing system 1 according to the present embodiment, according to the first example shown in FIG. 7, the memory controller 12 authenticates the semiconductor memory device 3 regardless of whether the semiconductor memory device 3 is valid or illegal. The content data T0 included in the content data with code T1 (N + 1) is input to the microprocessor 11. Accordingly, the received content data T0 can be input to the microprocessor 11 at an early stage without waiting for the completion of the process for authenticating the semiconductor memory device 3. When the microprocessor 11 determines that the semiconductor memory device 3 is illegal, the microprocessor 11 inputs a notification that the semiconductor memory device 3 is illegal to the microprocessor 11. Therefore, the microprocessor 11 can execute processing such as discarding or invalidating the content data T0 input from the memory controller 12.

  In the information processing system 1 according to the present embodiment, according to the second example shown in FIG. 8, when the memory controller 12 determines that the semiconductor storage device 3 is illegal, the content data with the authentication code The content data T0 included in T1 (N + 1) is not input to the microprocessor 11. Therefore, it is possible to prevent the content data T0 read from the unauthorized semiconductor storage device 3 from being input to the microprocessor 11 or the like.

  Further, according to the information processing system 1 according to the present embodiment, when the memory controller 12 determines that the semiconductor storage device 3 is illegal, the memory controller 12 performs subsequent communication between the memory controller 12 and the memory controller 21. Cut off. Accordingly, it is possible to prevent an access command from being transmitted from the communication device 2 to the unauthorized semiconductor storage device 3, content data being transmitted from the unauthorized semiconductor storage device 3 to the communication device 2, and the like. As a result, it is possible to prevent content data T0 from being read from the semiconductor memory device 3 illegally.

  Further, according to the information processing system 1 according to the present embodiment, the authentication control unit 63 includes the authentication code S (N) included in the read command with authentication code C1 (N) and the session generated by the key generation unit 61. The communication device 2 is authenticated depending on whether or not the authentication code S (N) generated based on the key K (N) matches. If the communication device 2 is illegal, the authentication code S (N) included in the access command with authentication code C1 (N) and the authentication code S (N) generated based on the session key K (N) are It does not match. Therefore, it is possible to reliably detect that the communication device 2 is illegal. The authentication control unit 53 also generates an authentication code S (N) generated based on the authentication code S (N + 1) included in the content data T1 (N + 1) with the authentication code and the session key K (N + 1) generated by the key generation unit 51. The semiconductor memory device 3 is authenticated depending on whether or not (N + 1) matches. If the semiconductor storage device 3 is illegal, the authentication code S (N + 1) included in the content data T1 (N + 1) with the authentication code and the authentication code S (N + 1) generated based on the session key K (N + 1) Does not match. Therefore, it is possible to reliably detect that the semiconductor memory device 3 is illegal.

  Further, according to the information processing system 1 according to the present embodiment, the authentication control unit 53 determines that the session length is longer when the bit length of the session key K (N) generated by the key generation unit 51 exceeds the allowable authentication code length. An authentication code S (N) is generated by compressing the key K (N). If the bit length of the session key K (N + 1) generated by the key generation unit 61 exceeds the allowable authentication code length, the authentication control unit 63 compresses the session key K (N + 1) to compress the authentication code S ( N + 1). Therefore, even if each bit length of the session keys K (N) and K (N + 1) exceeds the allowable authentication code length, the allowable authentication code can be obtained by compressing the session keys K (N) and K (N + 1). It is possible to generate authentication codes S (N) and S (N + 1) that fit within a long length.

  Further, according to the information processing system 1 according to the present embodiment, the key generation units 51 and 61 generate different session keys K for each authentication process. As a result, since the authentication code S generated by the authentication control units 53 and 63 is changed for each authentication process, the security strength can be improved.

  Further, according to the information processing system 1 according to the present embodiment, the authentication code S (N) included in the read command with authentication code C1 (N) transmitted from the memory controller 12 to the memory controller 21, and the read command The authentication code S (N + 1) included in the content data T1 (N + 1) with the authentication code transmitted from the memory controller 21 to the memory controller 12 in response to is different from each other. That is, the authentication code S (N) transmitted from the communication device 2 to the semiconductor storage device 3 and the authentication code S (N + 1) received from the semiconductor storage device 3 by the communication device 2 are different from each other. In this way, it is possible to improve the security strength by making the authentication code S different between transmission and reception.

  Also, according to the information processing system 1 according to the present embodiment, the authentication control unit 63 updates the session key K (() updated after the session key K (N) used when authenticating the communication device 2. N + 1) generates an authentication code S (N + 1). As a result, the authentication code S (N + 1) transmitted from the semiconductor storage device 3 to the communication device 2 can be easily and reliably changed from the authentication code S (N) transmitted from the communication device 2 to the semiconductor storage device 3. Become. Further, the authentication control unit 53 is generated by the key generation unit 51 and the updated second authentication code S (N + 1) generated based on the updated session key K (N + 1) generated by the key generation unit 61. The semiconductor memory device 3 is authenticated depending on whether or not the updated first authentication code S (N + 1) generated based on the updated session key K (N + 1) matches. If the semiconductor storage device 3 is valid, the updated second authentication code S (N + 1) matches the updated first authentication code S (N + 1), while the semiconductor storage device 3 If it is illegal, the updated second authentication code S (N + 1) does not match the updated first authentication code S (N + 1). Therefore, by confirming whether or not the updated second authentication code S (N + 1) matches the updated first authentication code S (N + 1), the semiconductor memory device 3 is valid or illegal. It is possible to easily and reliably determine whether there is any.

DESCRIPTION OF SYMBOLS 1 Information processing system 2 Communication apparatus 3 Semiconductor memory device 11 Microprocessor 12 Memory controller 21 Memory controller 22 Memory array 51 Key generation part 52 Encryption / decryption part 53 Authentication control part 61 Key generation part 62 Encryption / decryption part 63 Authentication control Part

Claims (13)

A communication device;
A storage device connected to the communication device and having a storage unit storing content data;
An information processing system comprising:
The communication device
Generating an access command with an authentication code by adding a first authentication code for authenticating the communication device to the storage device to an access command for accessing the storage unit;
Sending the access command with the authentication code to the storage device;
The storage device
Receiving the access command with the authentication code from the communication device;
Based on the first authentication code included in the access command with the authentication code, the communication device is authenticated,
An information processing system that accesses the storage unit based on the access command included in the access command with an authentication code when the communication device is determined to be valid. When the storage device determines that the communication device is valid,
Generating content data with an authentication code by adding a second authentication code for causing the communication device to authenticate the storage device to content data to be transmitted to the communication device in response to the access command;
Transmitting the content data with the authentication code to the communication device;
The communication device
Receiving the content data with the authentication code from the storage device;
The information processing system according to claim 1, wherein the storage device is authenticated based on the second authentication code included in the content data with the authentication code. The communication device
A main control unit for controlling the information processing system by software processing;
A first control circuit that is mounted separately from the main control unit and controls the storage device by hardware processing;
Have
The storage device
A second control circuit for controlling the storage unit;
The issuing of the access command is executed by the main control unit,
Generation and transmission of the access command with the authentication code, reception of the content data with the authentication code, and authentication of the storage device based on the second authentication code are executed by the first control circuit,
The reception of the access command with an authentication code, authentication of the communication device based on the first authentication code, and generation and transmission of the content data with the authentication code are executed by the second control circuit. 2. The information processing system according to 2.   The information processing system according to claim 3, wherein the second control circuit does not access the storage unit based on the access command when the communication device is determined to be illegal.   5. The information processing system according to claim 4, wherein the second control circuit further does not receive an access command transmitted from the first control circuit thereafter when the communication device determines that the communication device is illegal. 6.   When the first control circuit inputs content data included in the content data with the authentication code to the main control unit and determines that the storage device is unauthorized, a notification that the storage device is unauthorized The information processing system according to claim 3, wherein the information is input to the main control unit.   The said 1st control circuit does not input the content data contained in the said content data with an authentication code into the said main control part, when it determines with the said memory | storage device being unjust, The any one of Claims 3-5 Information processing system described in 1.   The first control circuit further cuts off subsequent communication between the first control circuit and the second control circuit when it is determined that the storage device is illegal. 8. The information processing system according to 7. The first control circuit includes:
A first number sequence generator for generating a first number sequence;
A first authentication control unit that generates the first authentication code based on the first number sequence;
Including
The second control circuit includes:
A second number sequence generation unit for generating a second number sequence identical to the first number sequence;
A second authentication control unit that generates the second authentication code based on the second number sequence;
Including
The second authentication control unit determines whether or not the first authentication code included in the access command with the authentication code matches the second authentication code generated based on the second number sequence. Authenticate the communication device;
The first authentication control unit determines whether the second authentication code included in the content data with the authentication code matches the first authentication code generated based on the first number sequence. The information processing system according to claim 3, wherein the storage device is authenticated. The first authentication control unit generates the first authentication code by compressing the first number sequence,
The information processing system according to claim 9, wherein the second authentication control unit generates the second authentication code by compressing the second number sequence.   The information processing system according to claim 9 or 10, wherein the first number sequence generation unit and the second number sequence generation unit generate the first number sequence and the second number sequence, which are different for each authentication process. .   The first authentication code included in the access command with the authentication code transmitted from the first control circuit to the second control circuit, and the second control circuit in response to the access command from the second control circuit. The information processing system according to claim 9, wherein the second authentication code included in the content data with the authentication code transmitted to one control circuit is different from each other. The second authentication control unit generates the second authentication code based on the updated second number sequence generated next to the second number sequence used when authenticating the communication device,
The first authentication control unit is based on the second authentication code and the updated first number sequence generated next to the first number sequence used when generating the first authentication code. The information processing system according to claim 12, wherein the storage device is authenticated based on whether or not the updated first authentication code generated in step 1 matches.

Images