JP5315422B2 - Data authentication method and data authentication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform collation processing and also reduce memory capacity required for authentication. <P>SOLUTION: Storage means which is accessible by an authentication device stores: content data; a first digest table 2 including first digest values concerning each of a plurality of pieces of partial data composing the content data; a second digest table 3 including second digest values concerning each of the plurality of partial data in the first digest table; and an electronic signature 4 generated from the second digest table. In a first read-out step, a memory of the authentication device reads out the second digest table and the electronic signature from the storage means. In a first authentication step, the authentication device authenticates validity of the content data by using the electronic signature read out by the memory and the second digest table read out by the memory. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a data authentication method, and more particularly to a data authentication method for authenticating that data is provided from a legitimate provider.

  Patent Document 1 describes a technique for authenticating the validity of program data stored in an information storage medium. In this technique, the information storage medium stores content data and a content hash table. The content hash table is data including a hash value (digest value) corresponding to each of data obtained by subdividing content data (subdivided content data). The information processing apparatus that reads the content data reads the fragmented content data and the digest value, and collates the hash value calculated from the fragmented content data with the read hash value. As a result, the information processing apparatus can execute the hash value calculation process and the collation process for each segmented content data. Therefore, when the information processing apparatus reads out a part of the content data, it is only necessary to perform the collation process for only the part that is actually read out.

  The information storage medium stores a content certificate obtained by applying a digital signature to the content hash value calculated from the content hash table and encrypting the content certificate. By performing the collation process using the content certificate, it is possible to accurately authenticate the validity of the content data even when the content data and the corresponding hash value are falsified. Specifically, the validity of the content data is verified by comparing the content hash value obtained by decrypting the content certificate with the content hash value obtained from the content hash table read from the information storage medium. Is possible.

JP 2006-74421 A

  In Patent Document 1, when an information processing apparatus authenticates the validity of data in an information storage medium using a content certificate, the information processing apparatus performs processing for calculating a content hash value from a content hash table. For this reason, the information processing apparatus needs to read the entire content hash table into the memory. That is, as the data size of the content hash table increases, the memory capacity to be prepared in the information processing apparatus also increases. Therefore, when it is difficult to mount a sufficient amount of memory as in the case where the information processing apparatus is a mobile device or the like, the memory capacity required for authentication may be insufficient. In order to reduce the data size of the content hash table, a method of reducing the number of hash values by increasing the data unit for subdividing the content data can be considered. However, with this method, the efficiency of the collation process performed when reading a part of the content data is deteriorated.

  Therefore, an object of the present invention is to provide a data authentication method capable of efficiently performing a matching process and reducing the memory capacity required for authentication.

The aspect of the present invention employs the following configuration in order to solve the above problems. Note that the reference numerals in parentheses and supplementary explanations in this section show the correspondence with the embodiments described later in order to help understanding of the aspects of the present invention , and limit the aspects of the present invention in any way. It is not a thing.

The first aspect is an authentication method used in an authentication device (game device 10) that authenticates content data (1). Content data, a first digest table (2), a second digest table (3), and an electronic signature (4) are stored in storage means (memory card 17) accessible by the authentication apparatus. The first digest table includes a primary digest value that is a digest value corresponding to partial content data constituting the content data. The second digest table includes a secondary digest value that is a digest value corresponding to a portion constituting the first digest table. The electronic signature is generated from the secondary digest value included in the second digest table. The authentication method includes a first reading step (S11) and a first authentication step (S12 to S14). In the first reading step, the second digest table and the electronic signature are read from the storage means to the memory (RAM 24) of the authentication device. In the first authentication step, the validity of the content data is authenticated using the electronic signature read into the memory and the secondary digest value included in the second digest table read into the memory.

In the first aspect , the content data is constituted by a plurality of partial content data. The primary digest value is calculated for each partial content data. The first digest table may include primary digest values corresponding to all partial content data. When generating an electronic signature, for example, a predetermined operation (such as an operation applying a hash function) is performed on data included in the second digest table (for example, all data included in the second digest table). Done. For example, the electronic signature may be data obtained by encrypting a digest value obtained by applying a predetermined hash function to data in the second digest table with a predetermined secret key. At this time, in the first authentication step, data generated by performing the predetermined calculation on the data included in the second digest table and data obtained by combining the electronic signature with the public key corresponding to the secret key It may be determined whether or not.

In the second aspect , the secondary digest value may be calculated for each group including a plurality of primary digest values. At this time, the authentication method includes a designation step (S21), a first calculation step (S24), a second authentication step (S25), a second calculation step (S27), and a third authentication step (S28). Is further included. In the designation step, partial content data to be read out from the partial content data is designated. In the first calculation step, a secondary digest value corresponding to the group is calculated from the group including the primary digest value corresponding to the designated partial content data. In the second authentication step, by comparing the secondary digest value calculated in the first calculation step with the secondary digest value corresponding to the group including the primary digest value corresponding to the designated partial content data Authenticate the validity of the content data. In the second calculation step, when the authentication in the second authentication step is successful, the digest value of the partial data is calculated from the specified partial data. In the third authentication step, the validity of the content data is authenticated by comparing the digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial data.

In the second aspect , in the specifying step, the authentication device includes the data to be read out according to the determination of the data to be read out (by a method such as random access) among the data included in the content data. The partial content data to be specified may be designated.

In the third aspect , the first authentication step may be executed after the authentication device and the storage unit are accessible and before the second authentication step is executed.

In the fourth aspect , the hash function for calculating the primary digest value from the partial content data and the hash function for calculating the secondary digest value from the partial first digest table may be the same.

In the fifth aspect , the electronic signature may be generated based on digest values corresponding to a plurality of secondary digest values included in the second digest table. At this time, the hash function for calculating the digest value has a higher security level than the hash function for calculating the primary digest value from the partial content data.

In the fifth aspect , when the security level of the hash function is high, the following cases are included.
(A) The number of processing bits in the process of calculating a hash value with a hash function is relatively large. (B) The number of bits of the hash value, which is the result calculated by the hash function, is relatively large.
(C) A function with encryption (as opposed to a function without encryption).

In the sixth aspect , the hash function for calculating the secondary digest value from the partial data of the first digest table is a digest value rather than the hash function for calculating the primary digest value from the partial data of the content data. The processing amount for calculating the value may be small.

In the sixth aspect , when the amount of processing for calculating the digest value is small, the following cases are included.
(A) The number of processing bits in the process of calculating a hash value with a hash function is relatively small.
(B) The number of bits of the hash value, which is the result calculated by the hash function, is relatively small.
(C) A function without encryption (as opposed to a function with encryption).

In the seventh aspect , the hash function used in the first authentication step is a hash function for calculating a secondary digest value from the partial first digest table, and a primary digest value from the partial content data. The security level may be higher than the hash function.

The eighth aspect is an authentication device (game device 10) that authenticates content data. The storage means (memory card 17) accessible by the authentication device includes content data, a first digest table including a primary digest value that is a digest value corresponding to partial content data constituting the content data, and the first digest table. A second digest table that includes a secondary digest value that is a digest value corresponding to a partial first digest table that constitutes one digest table, and an electronic signature that is generated from the secondary digest value included in the second digest table. It is remembered. The authentication device includes a reading unit (CPU core 21 or the like that executes step S11. Hereinafter, only the step number is described in the same case in this column) and an authentication unit (S12 to S14). The reading unit reads the second digest table and the electronic signature from the storage unit to the memory (RAM 24) of the authentication device. The authenticating unit authenticates the validity of the content data using the electronic signature read into the memory and the secondary digest value included in the second digest table read into the memory.

The ninth aspect is an authentication processing program executed in a computer (CPU core 21 or the like) of an authentication device (game device 10) that authenticates content data. The storage means (memory card 17) accessible by the authentication device includes content data, a first digest table including a primary digest value that is a digest value corresponding to partial content data constituting the content data, and the first digest table. A second digest table that includes a secondary digest value that is a digest value corresponding to a partial first digest table that constitutes one digest table, and an electronic signature that is generated from the secondary digest value included in the second digest table. It is remembered. The authentication processing program causes the computer to execute a reading step (S11) and an authentication step (S12 to S14). In the reading step, the computer reads the second digest table and the electronic signature from the storage unit to the memory of the authentication device. In the authentication step, the computer authenticates the validity of the content data using the electronic signature read into the memory and the secondary digest value included in the second digest table read into the memory.

The tenth aspect is a data processing method for generating data to be stored in the storage means. The data processing method includes a first calculation step (S1), a second calculation step (S2), an electronic signature generation step (S3), and a setting step (S4). In the first calculation step, a primary digest value that is a digest value corresponding to partial content data constituting the content data is calculated. In the second calculation step, a second digest value that is a digest value corresponding to the partial first digest table that constitutes the first digest table including the first digest value calculated in the first calculation step is calculated. In the electronic signature generation step, an electronic signature is generated from the second digest table including the second digest value calculated in the second calculation step. In the setting step, the content data, the first digest table, the second digest table, and the electronic signature are set as data to be stored in the storage means.

The eleventh aspect relates to a data structure. The data structure corresponds to content data, a first digest table that includes a first digest value that is a digest value corresponding to partial content that constitutes the content data, and a partial first digest table that constitutes the first digest table. A second digest table including a second digest value that is a digest value and an electronic signature generated from the second digest table are included.

According to the first, eighth to eleventh aspects , the authentication using the electronic signature is not performed by using the first digest table including the digest value of the content data, but the second digest table including the digest value of the first digest table. Done with. That is, the data to be read in the authentication process using the electronic signature is the second digest table having a data size smaller than that of the first digest table. Therefore, the memory capacity required for authentication can be reduced compared to the conventional case. According to the tenth and eleventh aspects , the data structure used in the above aspect can be provided.

According to the second aspect , the authentication device checks whether not only the second digest table but also the first digest table and the content data have been tampered with. Therefore, it is possible to authenticate the correctness of the content more accurately.

According to the third aspect , after the validity of the second digest table is authenticated in the first authentication step, the second and third authentication steps are executed. Since the second and third authentication steps are authentication processes based on the premise that the second digest table is valid, the second and third authentication steps are executed by executing the second and third authentication steps after the first authentication step. And the authentication in a 3rd authentication step can be performed correctly.

According to the fourth aspect , by making the hash function for calculating the primary digest value the same as the hash function for calculating the secondary digest value, compared to the sixth aspect described later, As a result of the hash function being broken, it is possible to reduce the possibility that the content data is freely falsified.

According to the fifth and seventh aspects , by increasing the security level of the hash function used for the electronic signature, it is possible to reduce the possibility of content data being freely altered as a result of the hash function being broken.

According to the sixth aspect , the processing amount of the second authentication step can be reduced as compared with the fourth aspect .

The figure which shows the data structure containing the content data used as the object of the authentication method in this embodiment The block diagram which shows the structure of the writing apparatus for writing each data shown in FIG. 1 to a memory card The flowchart which shows the flow of the process for writing each data shown in FIG. 1 in a memory card. External view of a game device which is an example of an authentication device according to the present embodiment Functional block diagram of game device The figure which shows the main data memorize | stored in RAM24 of the game device 10 The flowchart which shows the flow of the 1st authentication process performed in the game device 10. The flowchart which shows the flow of the 2nd and 3rd authentication process performed in the game device 10.

(1) Outline of the Present Invention First, an outline of an authentication method according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating a data structure including content data that is a target of an authentication method according to the present embodiment. The data structure shown in FIG. 1 includes content 1, a first digest table 2, a second digest table 3, and an electronic signature 4. Each data 1 to 4 shown in FIG. 1 is provided to the user of the content 1 in a form stored in a storage medium, or is provided from a storage unit on the server side to a playback device via a network such as the Internet.

  The content 1 is data to be provided to the user, such as a game program, video and / or audio data, text data, and the like. In the example described later, the content 1 is data used in a game program and game processing by the game program. In the present embodiment, the content 1 is divided for each predetermined data size, and data is read out in units of divided partial data (blocks).

  The first digest table 2 is data including a digest value (hash value) for each of a plurality of partial data constituting the content 1. In the present embodiment, the digest value included in the first digest table 2 may be referred to as a “primary digest value” for the purpose of distinguishing it from the digest value included in the second digest table 3. The primary digest value is calculated for each block of content 1. That is, the primary digest value is obtained by applying a hash function to partial data for one block of the content 1. In addition, the plurality of primary digest values included in the first digest table 2 are divided into a plurality of groups. In FIG. 1, four primary digest values surrounded by a solid line constitute one group. The number of primary digest values included in one group may be any number as long as it is plural.

  The second digest table 3 is data including a digest value for each of a plurality of partial data constituting the first digest table 2. In the present embodiment, the digest value included in the second digest table 3 may be referred to as a “secondary digest value” for the purpose of distinguishing it from the digest value included in the first digest table 2. The secondary digest value is calculated for each group of the first digest table 2. That is, the secondary digest value is obtained by applying a hash function to the data of the primary digest value for one group. In FIG. 1, a secondary digest value a is obtained by applying a hash function to a group consisting of data of primary digest values A to D, and a group consisting of data of primary digest values E to H is obtained. A secondary digest value b is obtained by applying a hash function.

  The electronic signature 4 is electronic signature data generated from the second digest table 3. Specifically, the electronic signature 4 encrypts a digest value obtained by applying a predetermined hash function to a secondary digest value included in the second digest table 3 by encryption using a public key encryption method. Data.

  Next, an outline of the content authentication method when the data structure shown in FIG. 1 is adopted will be described. Note that the authentication of the content 1 is authentication that the content 1 is data provided from a valid provider, that is, that the content 1 has not been tampered with by a person other than the valid provider. The authentication process for the content 1 includes three stages of processes of a first authentication process to a third authentication process. The first authentication process is a process for authenticating the validity of the second digest table 3 using the second digest table 3 and the electronic signature 4. That is, in the first authentication process, authentication is performed by comparing the digest value calculated from the second digest table with the digest value obtained by decrypting the electronic signature 4. The second authentication process is a process for authenticating the validity of one group included in the first digest table 2. That is, in the second authentication process, authentication is performed by comparing the digest value calculated from the first digest table 2 with the secondary digest value included in the second digest table 3. The third authentication process is a process for authenticating the validity of one block included in the content 1. In the third authentication process, authentication is performed by comparing the digest value calculated from one block of the content 1 with the primary digest value included in the first digest table 2.

  In the first to third authentication processes, it is not necessary to read the entire data of the first digest table 2 into the memory at a time. This is because in the second authentication process, only one group included in the first digest table 2 is authenticated. Therefore, in the present embodiment, the memory area required for the authentication process can be reduced as compared with the conventional case where the entire data of the first digest table 2 is read into the memory at a time.

For example, consider a case where the data size of content 1 is 256 MB (bytes), the digest unit (data size to which the hash function is applied) is 2 KB, and the data size of the digest value is 16 B. In this case, from the following equation (1), the data size of the first digest table is 2 MB.
(256 [MB] / 2 [KB]) × 16 [B] = 2 [MB] (1)
Also, when calculating the secondary digest value from the group of the first digest table, assuming that the digest unit is 2 KB and the data size of the digest value is 16 B, the data of the second digest table 3 is obtained from the following equation (2). The size will be 16KB.
2 [MB] / 2 [KB] * 16 [B] = 16 [KB] (2)
The data size of the digest unit or digest value can be arbitrarily determined in each of the case where the primary digest value is calculated from the content 1 and the case where the secondary digest is calculated from the first digest table 2. . Therefore, the data size of the second digest table can be changed as appropriate by appropriately changing the data size of the digest unit or digest value. Here, although details of the first to third authentication processes will be described later, in the present embodiment, the authentication apparatus needs to read the entire second digest table 3 into the memory, while the first digest table 2. Only one group needs to be read into the memory. That is, the data size of the second digest table 3, that is, a 16 KB memory area may be prepared for authentication processing. On the other hand, in the conventional method, since the entire first digest table 2 needs to be read, a 2 MB memory area must be prepared for authentication processing. As described above, according to the present embodiment, the memory area required for the authentication process can be significantly reduced as compared with the conventional case. In addition, by adjusting the data size of the second digest table, it is possible to adjust the size of the memory area required for the authentication process in consideration of random accessibility and memory capacity.

  Details of the processing in this embodiment will be described below. In the following, the content to be provided to the content user is a game program, the data 1 to 4 shown in FIG. 1 are stored in the memory card and provided to the content user, and the game program in the memory card is portable. A case will be described as an example in which it is read and executed by a game device of a type.

(2) Data Generation Process on Content Providing Side First, details of the process for generating the data structure shown in FIG. 1 will be described with reference to FIGS. FIG. 2 is a block diagram showing a configuration of a writing device for writing each data shown in FIG. 1 into a memory card. In FIG. 2, the writing device 6 includes a storage unit 7, a control unit 8, and a writing unit 9. The writing device 6 is provided on the provider side of the content 1.

  The storage unit 7 illustrated in FIG. 2 stores the content 1, a hash function for calculating a digest value, and an encryption key used for generating an electronic signature. The control unit 8 uses the data stored in the storage unit 7 to generate the first and second digest tables 2 and 3 and the electronic signature 4. The writing unit 9 can access a memory card 17 that is an example of a storage medium, and writes data to the memory card 17 in accordance with an instruction from the control unit 8.

  FIG. 3 is a flowchart showing a flow of processing for writing each data shown in FIG. 1 into the memory card. The process shown in FIG. 3 is executed by the control unit 8 of the writing device 6. Typically, the process shown in FIG. 3 is executed when the control unit 8 executes a predetermined data generation program.

  In step S <b> 1 shown in FIG. 3, the control unit 8 generates the first digest table 2 from the content 1 stored in the storage unit 7. That is, a plurality of primary digest values included in the first digest table 2 are calculated. As described above, the primary digest value is calculated for each block included in the content 1. That is, the control unit 8 calculates a plurality of primary digest values corresponding to each block by applying a hash function to each block of the content 1. Note that the hash function used for calculating the primary digest value is referred to as a first hash function. The first hash function is stored in the storage unit 7. The plurality of primary digest values calculated in step S1 are stored in the storage unit 7 as the first digest table 2.

  In step S2, the control unit 8 generates a second digest table 3 from the first digest table 2 calculated in step S1. That is, a plurality of secondary digest values included in the second digest table 3 are calculated. As described above, the secondary digest value is calculated for each group included in the first digest table 2. That is, the control unit 8 calculates a plurality of secondary digest values corresponding to each group by applying a hash function to each group of the first digest table 2. Note that the hash function used to calculate the secondary digest value is referred to as a second hash function. The second hash function is stored in the storage unit 7. In the present embodiment, the first hash function and the second hash function are the same. More specifically, in the present embodiment, MD-5 (Message Digest 5) is used as the first hash function and the second hash function. The plurality of secondary digest values calculated in step S <b> 2 are stored in the storage unit 7 as the second digest table 3.

  In step S <b> 3, the control unit 8 generates the electronic signature 4 from the second digest table 3. Specifically, the control unit 8 first calculates a digest value of the second digest table 3 by applying a predetermined electronic signature generation hash function to the second digest table 3. In the present embodiment, a hash function for generating an electronic signature is different from the first and second hash functions. Specifically, SHA-1 (Secure Hash Algorithm 1) is used as a hash function for generating an electronic signature. Further, the control unit 8 generates the electronic signature 4 by encrypting the calculated digest value with the secret key. The secret key is an encryption key that is paired with a public key used on the game device side that uses the content 1 (game program), and is stored in the storage unit 7. The electronic signature 4 generated as described above is stored in the storage unit 7.

  In step S 4, the first digest table 2, the second digest table 3, and the electronic signature 4 generated in steps S 1 to S 3 are written to the memory card 17 together with the content 1. That is, the control unit 8 gives an instruction to write these data 1 to 4 to the memory card 17 to the writing unit 9. The writing unit 9 writes each data 1 to 4 in the memory card 17 in accordance with this instruction. The memory card 17 includes a ROM 17a and a RAM 17b (see FIG. 5), and the data 1 to 4 are written in the ROM 17a. After step S4, the control unit 8 ends the process shown in FIG.

  In the present embodiment, the memory card 17 in which the data 1 to 4 is written in the steps S1 to S4 is provided from the content provider to the content user. The content user uses the content (game program) 1 in the memory card 17 by attaching the acquired memory card 17 to the game apparatus 10 shown in FIG.

(3) Authentication Process on Content Use Side Details of the content 1 authentication process performed on the content use side will be described with reference to FIGS. FIG. 4 is an external view of a game device that is an example of the authentication device according to the present embodiment. In FIG. 1, the game apparatus 10 includes a first LCD (Liquid Crystal Display) 11 and a second LCD 12 that are display means, a housing 13, an operation switch unit 14, and a touch panel 15. Further, the memory card 17 is detachably attached to the game apparatus 10.

  The housing 13 includes an upper housing 13a and a lower housing 13b. The first LCD 11 is accommodated in the upper housing 13a, and the second LCD 12 is accommodated in the lower housing 13b. The resolutions of the first LCD 11 and the second LCD 12 are both 256 dots × 192 dots. In this embodiment, an LCD is used as the display device. However, any other display device such as a display device using EL (Electro Luminescence) can be used. An arbitrary resolution can be used.

  The upper housing 13a is formed with sound release holes 18a and 18b for emitting sound from the pair of speakers 30a and 30b to the outside.

  The lower housing 13b is provided with an insertion slot for mounting the memory card 17. Also, the lower housing 13b has an operation switch section 14, that is, a cross switch 14a, a start switch 14b, a select switch 14c, an A button 14d, a B button 14e, an X button 14f, a Y button 14g, and an L button as an input device. 14L and an R button 14R are provided. As a further input device, a touch panel 15 is mounted on the screen of the second LCD 12. The lower housing 13 b is provided with a sound hole 33 a around the second LCD 12. The microphone 33 is provided inside the housing 13b in the vicinity of the sound hole, and inputs a sound outside the housing that enters from the sound hole 33a and converts the sound into an electric signal (audio signal). The lower housing 13b is provided with an insertion slot for storing the power switch 19, the memory card 17 and the stick 16.

  As the touch panel 15, an arbitrary system such as a resistive film system, an optical system (infrared system), and a capacitive coupling system can be used. The touch panel 15 has a function of outputting coordinate data corresponding to the contact position when the surface of the touch panel 15 is touched with the stick 16. In the following description, it is assumed that the player operates the touch panel 15 with the stick 16, but it is of course possible to operate the touch panel 15 with a pen (stylus pen) or a finger instead of the stick 16. In the present embodiment, the touch panel 15 having a resolution (detection accuracy) of 256 dots × 192 dots is used as in the resolution of the second LCD 12. However, the resolution of the touch panel 15 and the resolution of the second LCD 12 do not necessarily match.

  Next, the internal configuration of the game apparatus 10 will be described with reference to FIG. In FIG. 5, a CPU core 21 is mounted on the electronic circuit board 20 accommodated in the housing 13. A connector 23 is connected to the CPU core 21 via a bus 22, an input / output interface circuit (referred to as I / F circuit in the drawing) 25, a first GPU (Graphics Processing Unit) 26, a second GPU 27, a RAM 24, And the LCD controller 31 is connected. The memory card 17 is detachably connected to the connector 23. The memory card 17 includes a ROM 17a that stores data 1 to 4 shown in FIG. 1 and a RAM 17b that stores backup data in a rewritable manner. The game program (content 1) stored in the ROM 17a of the memory card 17 is loaded into the RAM 24 which is a storage means of the game apparatus 10, and the game program loaded into the RAM 24 is executed by the CPU core 21. In addition to the game program, the RAM 24 stores temporary data obtained by the CPU core 21 executing the game program and data for generating a game image.

  The operation switch unit 14, the touch panel 15, the right speaker 30 a, the left speaker 30 b, and the microphone 33 are connected to the I / F circuit 25. The right speaker 30a and the left speaker 30b are respectively arranged inside the sound release holes 18a and 18b. When outputting game sound effects or the like, the CPU core 21 sends audio data (sound source) stored in the RAM 24 or the like from the I / F circuit 25 to each speaker 30a via an A / D conversion circuit, amplifier, or the like (not shown). To 30b. Thereby, each speaker 30a and 30b outputs the audio | voice represented by audio | voice data. Also, audio data indicating audio input to the microphone 33 is stored in the RAM 24 via the I / F circuit 25.

  A first VRAM (Video RAM) 28 is connected to the first GPU 26, and a second VRAM 29 is connected to the second GPU 27. In response to an instruction from the CPU core 21, the first GPU 26 generates a first game image based on data for generating a game image stored in the RAM 24, and draws the first game image in the first VRAM 28. Similarly, the second GPU 27 generates a second game image in accordance with an instruction from the CPU core 21 and draws it in the second VRAM 29. The first VRAM 28 and the second VRAM 29 are connected to the LCD controller 31.

  The LCD controller 31 includes a register 32. The register 32 stores a value of 0 or 1 according to an instruction from the CPU core 21. When the value of the register 32 is 0, the LCD controller 31 outputs the first game image drawn in the first VRAM 28 to the first LCD 11 and outputs the second game image drawn in the second VRAM 29 to the second LCD 12. . When the value of the register 32 is 1, the first game image drawn in the first VRAM 28 is output to the second LCD 12, and the second game image drawn in the second VRAM 29 is output to the first LCD 11.

  Note that the configuration of the game apparatus 10 as described above is merely an example, and the authentication apparatus according to the present invention can be realized by any computer system that reproduces and / or executes the content 1.

  Hereinafter, details of the authentication process performed in the game apparatus 10 will be described. FIG. 6 is a diagram showing main data stored in the RAM 24 of the game apparatus 10. 6, the RAM 24 is provided with an authentication program storage area 41, a content storage area 42, a first hash function storage area 43, a second hash function storage area 44, and a digital signature data storage area 45.

  The authentication program storage area 41 stores an authentication program for executing an authentication process for the content 1. The authentication program is not a program acquired from the memory card 17 but is stored in advance.

  In the content storage area 42, a part of data of the content 1 stored in the memory card 17 is stored. The game apparatus 10 appropriately reads out the partial data required in the content 1 to the content storage area 42 and executes the game process using the read partial data.

  The first hash function storage area 43 stores the first hash function. The second hash function storage area 44 stores the second hash function. The data of the first and second hash functions is stored in advance as in the authentication program. If the first hash function and the second hash function are the same hash function, only one of the first and second hash function storage areas 43 and 44 may be provided.

  The electronic signature data storage area 45 stores data necessary for authentication using the electronic signature 4, that is, the electronic signature generation hash function and public key data. This public key is a key that is paired with the encryption key stored in the writing device 6. Note that data necessary for authentication using the electronic signature 4 is stored in advance as in the authentication program.

  In addition to the data stored in the storage areas 41 to 45, the RAM 24 stores various data used in an authentication process described later.

  Next, details of the authentication process will be described. In the present embodiment, the authentication process includes an authentication process (first authentication process) executed when the memory card 17 is attached to the game apparatus 10, and the game apparatus 10 reads the data of the content 1 from the memory card 17. It is divided into processes (second and third authentication processes) executed at the time. Specifically, the first authentication process is executed in response to the memory card 17 being attached to the game apparatus 10, and the second and third authentication processes are performed by the game apparatus 10 from the memory card 17 to the content 1 data. It is executed when reading.

  FIG. 7 is a flowchart showing the flow of the first authentication process executed in the game apparatus 10. The first authentication process shown in FIG. 7 is executed in response to the memory card being inserted into the game apparatus 10. The first authentication process is executed regardless of whether the content stored in the memory card is from a valid provider. Note that the game apparatus 10 does not read the content 1 until the reading of the content 1 is permitted in the first authentication process.

  In step S <b> 11 shown in FIG. 7, the CPU core 21 reads the second digest table 3 and the electronic signature 4 from the memory card 17 attached to the game apparatus 10 into the RAM 24. In steps S12 to S16 executed after step S11, the first authentication process, that is, the authentication process of the content 1 using the second digest table 3 and the electronic signature 4 is performed.

  In subsequent step S <b> 12, the CPU core 21 generates a digest value by decrypting the read electronic signature 4. The decryption process of the electronic signature 4 is performed using the public key data stored in the electronic signature data storage area 45. In step S13, a digest value is calculated from the read second digest table 3. The digest value is calculated by applying a digital signature generation hash function to the second digest table 3. The electronic signature generation hash function is stored in the electronic signature data storage area 45. In other embodiments, the process of step S12 and the process of step S13 may be executed first or may be executed in parallel.

  In step S14, the CPU core 21 determines whether or not the digest value generated in step S12 matches the digest value calculated in step S13. If these two digest values match, it is determined that the authentication in the first authentication process has succeeded, and the process of step S15 is executed. On the other hand, if these two digest values do not match, it is determined that the authentication in the first authentication process has failed, and the process of step S16 is executed.

  In step S15, reading of the content 1 (execution of the game process) is permitted, and the CPU core 21 ends the first authentication process shown in FIG. Thereby, the game process using the content 1 is executed after step S15. In step S15, the authenticity of the content 1 is authenticated in the authentication by the first authentication process. In the present embodiment, even if the validity of the content 1 is authenticated in the authentication by the first authentication process, the validity of the content 1 in the second authentication process and the third authentication process executed after the first authentication process. May not be authenticated.

  On the other hand, in step S16, reading of the content 1 (execution of game processing) is prohibited. At this time, since it is impossible to execute the game program included in the content 1, the CPU core 21 ends the process shown in FIG. In step S16, the CPU core 21 displays a message (for example, “This memory card cannot be used”) indicating that the content 1 in the memory card 17 is illegal on the screen of the first LCD 11 or the second LCD 12. You may make it make it.

  After the first authentication process shown in FIG. 7 is completed, the CPU core 21 deletes the digest value calculated from the second digest table stored in the RAM 24 and the data of the electronic signature 4 from the RAM 24. It doesn't matter. In the present embodiment, the second digest table is stored in the RAM 24 because it is used in the second authentication process described later.

  When the validity of the content 1 is authenticated in the first authentication process, the CPU core 21 reads and executes the game program included in the content 1 and the game data (image data and sound) included in the content 1. The game process is advanced by performing a process of reading out data and the like. Here, the data of the content 1 is read into the game apparatus 10 in units of blocks. Further, when partial data for one block of the content 1 is read, the second authentication process and the third authentication process are executed. Details of the second authentication process and the third authentication process will be described below.

  FIG. 8 is a flowchart showing the flow of the second and third authentication processes executed in the game apparatus 10. The second and third authentication processes shown in FIG. 8 are executed in response to the game device 10 reading the content 1 for one block. Note that the game apparatus 10 does not use the content 1, that is, does not execute the game process based on the content 1, until the use of the content 1 read in the second and third authentication processes is permitted.

  In step S <b> 21 shown in FIG. 8, the CPU core 21 specifies a block of partial content data to be read out of the partial data (partial content data) of the content 1. Note that the content partial data to be read is determined by the game processing executed so far. In addition, among the blocks included in the content 1, the block including the partial content data to be read first is determined in advance, and when the game apparatus 10 reads the content for the first time, the CPU core 21 reads the block in advance. Specify a given block.

  A second authentication process is executed in steps S22 to S25 after step S21. In the second authentication process, the validity of the primary digest value included in the group corresponding to the block designated in step S21 among the groups included in the first digest table 2 is authenticated.

  In step S22, the CPU core 21 designates a group corresponding to the block designated in step S21. That is, a group including the primary digest value corresponding to the partial content data included in the block is designated. For example, when the block A shown in FIG. 1 is designated, a group composed of the primary digest values A to D is designated as a group corresponding to the block A.

  In subsequent step S <b> 23, the CPU core 21 reads the primary digest value of the designated group from the memory card 17. The read data is stored in the RAM 24. In step S23, the new group data is stored in the RAM 24 by overwriting the group data stored in the RAM 24 in the previous step S23. That is, since only the latest one group of data is stored in the RAM 24, a storage area for one group may be prepared in the RAM 24 as a storage area for the first digest table.

  Further, in step S24, a second digest value corresponding to the group is calculated from the primary digest value of the designated group. The digest value is calculated by applying the second hash function to a plurality of first digest values included in the designated group. The second hash function is stored in the second hash function storage area 44.

  In step S25, the CPU core 21 determines whether or not the secondary digest value calculated in step S24 matches the secondary digest value corresponding to the designated group. The secondary digest value is obtained from the second digest table 3 already read into the RAM 24 in step S11 shown in FIG. For example, when a group composed of the primary digest values A to D shown in FIG. 1 is designated, the secondary digest value corresponding to the group becomes the secondary digest value a shown in FIG. If the two digest values match in the determination in step S25, it is determined that the authentication in the second authentication process is successful, and the process in step S26 is executed. On the other hand, if these two digest values do not match, it is determined that the authentication in the second authentication process has failed, and the process of step S30 is executed.

  When the authentication in the second authentication process is successful, the third authentication process is executed in steps S26 to S29. In the third authentication process, the validity of the block designated in step S21 among the blocks included in the content 1 is authenticated.

  In step S <b> 26, the CPU core 21 reads the designated block (partial content data included in the block) from the memory card 17. The read data is stored in the content storage area 42 of the RAM 24. The content storage area 42 only needs to store at least one block of content 1, but a plurality of blocks (for example, two blocks) of content may be stored in the content storage area 42.

  In subsequent step S27, a primary digest value corresponding to the designated block is calculated. This digest value is calculated by applying the first hash function to the partial content data included in the designated block. The first hash function is stored in the first hash function storage area 43.

  In step S28, the CPU core 21 determines whether or not the primary digest value corresponding to the designated block matches the first digest value calculated in step S27. The primary digest value is obtained from the first digest table 2 already read into the RAM 24 in step S23. If these two digest values match, it is determined that the authentication in the third authentication process is successful, and the process of step S29 is executed. On the other hand, if these two digest values do not match, it is determined that the authentication in the third authentication process has failed, and the process of step S30 is executed.

  In step S29, the CPU core 21 permits use of the read block and executes processing based on the block. For example, if the read block is a game program, the CPU core 21 executes the game program to execute the game process. In the present embodiment, the content 1 may be encrypted in units of blocks, for example. If the content 1 is encrypted, the encrypted content 1 data is stored in step S29 (or step S26). Good). After step S29, the CPU core 21 ends the process shown in FIG. Thereafter, if it is necessary to read the content 1 in the game process, the process shown in FIG. 8 is performed again. The process shown in FIG. 8 is performed every time the block of content 1 is read.

  In other embodiments, the first and second digest tables 2 and 3 stored in the memory card 17 may be encrypted in the same manner as the content 1. At this time, the CPU core 21 decrypts the first digest table 2 in step S23. Further, the second digest table 3 is decoded in step S11. Further, the method and key for encrypting the data 1 to 3 do not need to match.

  On the other hand, in step S30, the use of the content 1 is prohibited, and the CPU core 21 ends the process shown in FIG. In step S30, as in step S16, a message indicating that the content 1 in the memory card 17 is illegal may be displayed on the screen of the first LCD 11 or the second LCD 12. Further, after step S30, the CPU core 21 stops the game process even if the game process is being executed.

  As described above, according to the present embodiment, in the first to third authentication processes, it is not necessary to read the entire first digest table 2 to the RAM 24, and the second digest table 3 and the first digest table 2 Authentication can be performed simply by reading one group. Therefore, the memory area required for the authentication process can be reduced as compared with the conventional method of reading the entire first digest table 2.

  When the content storage area 42 can store data of content 1 for a plurality of blocks, the second and third authentication processes are omitted for the content 1 data already stored in the content storage area 42. You may do it. Specifically, in the process shown in FIG. 8, the CPU core 21 determines whether or not the block specified in step S21 is already stored in the content storage area 42 before the process in step S22. It may be. And when the block is already memorize | stored, the process of step S22-S28 may be skipped and the process of step S29 may be performed.

  In the above-described embodiment, it is preferable to use a hash function stronger than the first and second hash functions (i.e., hard to break, that is, has a high security level) as the hash function for generating an electronic signature. This is because the hash function for generating an electronic signature is used only once when the memory card 17 is inserted, and therefore it is preferable to use a function that places importance on security. The security level of the hash function is determined by the number of bits in the digest value calculation process, the number of bits in the digest value, whether encryption is performed, and the like. That is, it can be said that a hash function having a relatively large number of bits in a digest value calculation process or a digest value is stronger than a hash function having a relatively small number of bits. Further, it can be said that the hash function with encryption (the hash function with key) is relatively stronger than the hash function without encryption.

  In the above embodiment, the first hash function and the second hash function are the same. Here, in another embodiment, the first hash function and the second hash function may be different for the purpose of reducing the processing amounts of the second authentication process and the third authentication process. At this time, it is preferable to use a hash function having a smaller processing amount for calculating the digest value than the first hash function as the second hash function. In other words, it is preferable to use a hash function stronger than the second hash function as the first hash function. For example, in another embodiment, it is conceivable to use SHA-1 as the first hash function and MD-5 as the second hash function. At this time, since the electronic signature generation hash function is preferably stronger than the first and second hash functions, SHA-256, for example, is used as the electronic signature generation hash function.

  The reason why a hash function stronger than the second hash function is used as the first hash function is that it is easier to tamper the content 1 when the first hash function is broken than when the second hash function is broken. Since the first hash function indicates the relationship between the content 1 and the primary digest value, the content 1 can be directly tampered with when the first hash function is broken, while the second hash function is broken. Content 1 cannot be altered directly. Therefore, if the security level of any hash function is lowered for the purpose of reducing the processing amount of the second authentication process and the third authentication process, it is preferable to lower the security level of the second hash function.

  Moreover, in the said embodiment, the data structure shown in FIG. 1 was memorize | stored in storage media, such as a memory card, and the form provided to a content user was demonstrated as an example. Here, in another embodiment, the data structure shown in FIG. 1 may be provided to a content user by communication via a network. For example, the present invention can also be applied to a system in which an authentication device (for example, the game device 10) and a server device storing the data structure can communicate via a network. Note that the operation of the authentication device in this system is the same processing as in the above embodiment, except that processing for receiving data from the server device is performed instead of processing for reading data from the memory card.

  The present invention is applied to, for example, a system that provides a user with a game program, a game device used in the system, and the like for the purpose of efficiently performing verification processing and reducing the memory capacity required for authentication Is possible.

DESCRIPTION OF SYMBOLS 1 Content 2 1st digest table 3 2nd digest table 4 Electronic signature 6 Writing device 7 Storage part 8 Control part 9 Writing part 10 Game device 17 Memory card 21 CPU core 24 RAM
41 Authentication program storage area 42 Content storage area 43 First hash function storage area 44 Second hash function storage area 45 Data storage area for electronic signature

Claims (61)

A method used in an authentication device for authenticating content data,
The authentication device has accessible storage means, the content data, a first digest table including primary digest values that correspond to a plurality of partial content data constituting the content data, the plurality of partial content data A second digest table including a secondary digest value calculated for each group of primary digest values corresponding to, and an electronic signature generated using the secondary digest value are stored ,
A first authentication step for performing authentication by the electronic signature ;
A designation step of designating partial content data to be read out of the plurality of partial content data by random access;
A first calculation step of calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authentication step for authenticating the validity of the content data,
A second calculation step of calculating a primary digest value of the partial content data from the specified partial content data;
The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. A third authentication step for authenticating the authentication method. 2. The authentication according to claim 1, further comprising a reading step of reading a group including a primary digest value corresponding to the designated partial content data from the storage unit to the memory of the authentication device before the first calculation step. Method. The authentication according to claim 1 or 2, wherein a process based on the partial content data designated by the designation step is executed on the condition that the validity is authenticated by the second authentication step and the third authentication step. Method. The authentication method according to any one of claims 1 to 3, wherein in the designation step, partial content data to be used next is designated as needed in accordance with execution of processing based on the content data. 5. The authentication method according to claim 1, wherein the process based on the content data is executed on condition that the validity is authenticated in the first authentication step. The first authentication step is executed after the authentication device and the storage unit are accessible, and before the second authentication step and the third authentication step are executed . An authentication method according to any one of the above. Characterized in that the hash function for calculating a primary digest value from said partial content data, the hash function for calculating a second digest value before Symbol first digest table is the same, according to claim 1 The authentication method in any one of -6 . The electronic signature is generated based on a digest value corresponding to a plurality of secondary digest values included in a second digest table, and a hash function for calculating the digest value is obtained from the partial content data using a primary digest value. wherein the higher security level than the hash function to calculate the authentication method according to any of claims 1 to 7. The hash function for calculating a second digest value before Symbol first digest table, than the hash function for calculating a primary digest value from said partial content data, a small amount of processing for calculating the digest value The authentication method according to claim 1, wherein: The digital signature is generated based on the digest values corresponding to the plurality of secondary digest value included in the second digest table, the secondary from the hash function, before Symbol first digest table for calculating the digest value hash function for calculating the digest value, and wherein the security level is higher than the hash function for calculating a primary digest value from said partial content data, according to any of claims 1 to 6 Authentication method. An authentication device for authenticating content data,
The authentication device has accessible storage means, the content data, a first digest table including primary digest values that correspond to a plurality of partial content data constituting the content data, the plurality of partial content data A second digest table including a secondary digest value calculated for each group of primary digest values corresponding to, and an electronic signature generated using the secondary digest value are stored ,
A first authentication means for performing authentication with the electronic signature,
Designating means for designating partial content data to be read out of the plurality of partial content data by random access;
First calculation means for calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authenticating means for authenticating the validity of the content data;
Second calculating means for calculating a primary digest value of the partial content data from the specified partial content data;
The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. And a third authentication means for authenticating the authentication device. An authentication processing program executed in a computer of an authentication device for authenticating content data,
The authentication device has accessible storage means, the content data, a first digest table including primary digest values that correspond to a plurality of partial content data constituting the content data, the plurality of partial content data A second digest table including a secondary digest value calculated for each group of primary digest values corresponding to, and an electronic signature generated using the secondary digest value are stored ,
A first authentication step for performing authentication by the electronic signature ;
A designation step of designating partial content data to be read out of the plurality of partial content data by random access;
A first calculation step of calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authentication step for authenticating the validity of the content data,
A second calculation step of calculating a primary digest value of the partial content data from the specified partial content data;
The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. and a third authentication step for authenticating the causes the computer to perform the authentication processing program.   A computer-readable storage medium storing a data structure used in an authentication device for authenticating content data,
  The data structure is
    The content data;
    A first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data;
    A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the plurality of partial content data;
    An electronic signature generated using the secondary digest value,
  The first digest table, the second digest table, and the electronic signature are data supplied to a memory of the authentication device,
  In the authentication device, first authentication by the electronic signature is performed,
  The plurality of partial content data is data in which partial content data to be read out of the plurality of partial content data is supplied to the memory of the authentication device by random access,
  In the authentication apparatus, a secondary digest value corresponding to the group is calculated from a group including a primary digest value corresponding to the supplied partial content data included in the primary digest table, and the calculated secondary By comparing the digest value with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the supplied partial content data, the validity of the content data is verified. Second authenticated,
  In the authentication apparatus, a primary digest value of the partial content data is calculated from the supplied partial content data, and the primary digest value corresponding to the calculated primary digest value and the supplied partial content data is calculated. A storage medium in which the validity of the content data is third-authenticated by collating with a primary digest value included in a table.   An authentication system for authenticating content data,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature generated using the secondary digest value are stored;
  First authentication means for performing authentication by the electronic signature;
  Designating means for designating partial content data to be read out of the plurality of partial content data by random access;
  First calculation means for calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
  The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authenticating means for authenticating the validity of the content data;
  Second calculating means for calculating a primary digest value of the partial content data from the specified partial content data;
  The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. An authentication system comprising: third authentication means for authenticating   A method used in an authentication device for authenticating content data,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature generated using the secondary digest value are stored;
  A first authentication step for performing authentication by the electronic signature;
  A designation step for sequentially designating partial content data to be read out of the plurality of partial content data during execution of the content data;
  A first calculation step of calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
  The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authentication step for authenticating the validity of the content data,
  A second calculation step of calculating a primary digest value of the partial content data from the specified partial content data;
  The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. A third authentication step for authenticating the authentication method.   16. The authentication according to claim 15, further comprising a read step of reading a group including a primary digest value corresponding to the designated partial content data from the storage unit to the memory of the authentication device before the first calculation step. Method.   The authentication according to claim 15 or 16, wherein a process based on the partial content data designated by the designation step is executed on the condition that the legitimacy is authenticated by the second authentication step and the third authentication step. Method.   The authentication method according to any one of claims 15 to 17, wherein in the designation step, partial content data to be used next is designated as needed in accordance with execution of processing based on the content data.   The authentication method according to claim 15, wherein the process based on the content data is executed on the condition that the validity is authenticated by the first authentication step.   The first authentication step is executed after the authentication device and the storage unit are accessible, and before the second authentication step and the third authentication step are executed. An authentication method according to any one of the above.   16. The hash function for calculating a primary digest value from the partial content data and the hash function for calculating a secondary digest value from the first digest table are the same. The authentication method according to any one of 20.   The electronic signature is generated based on a digest value corresponding to a plurality of secondary digest values included in a second digest table, and a hash function for calculating the digest value is obtained from the partial content data using a primary digest value. The authentication method according to any one of claims 15 to 21, wherein the security level is higher than a hash function for calculating the value.   The hash function for calculating the secondary digest value from the first digest table has a smaller processing amount for calculating the digest value than the hash function for calculating the primary digest value from the partial content data. The authentication method according to any one of claims 15 to 21, characterized in that:   The electronic signature is generated based on digest values corresponding to a plurality of secondary digest values included in the second digest table, and a hash function for calculating the digest value is obtained from the first digest table. The security level is higher than a hash function for calculating a value and a hash function for calculating a primary digest value from the partial content data, according to any one of claims 15 to 21, Authentication method.   An authentication device for authenticating content data,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature generated using the secondary digest value are stored;
  First authentication means for performing authentication by the electronic signature;
  Designation means for sequentially designating partial content data to be read from among the plurality of partial content data during execution of the content data;
  First calculation means for calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
  The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authenticating means for authenticating the validity of the content data;
  Second calculating means for calculating a primary digest value of the partial content data from the specified partial content data;
  The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. And a third authentication means for authenticating the authentication device.   An authentication processing program executed in a computer of an authentication device for authenticating content data,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature generated using the secondary digest value are stored;
  A first authentication step for performing authentication by the electronic signature;
  A designation step for sequentially designating partial content data to be read out of the plurality of partial content data during execution of the content data;
  A first calculation step of calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
  The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authentication step for authenticating the validity of the content data,
  A second calculation step of calculating a primary digest value of the partial content data from the specified partial content data;
  The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. An authentication processing program for causing the computer to execute a third authentication step for authenticating.   A computer-readable storage medium storing a data structure used in an authentication device for authenticating content data,
  The data structure is
    The content data;
    A first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data;
    A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the plurality of partial content data;
    An electronic signature generated using the secondary digest value,
  The first digest table, the second digest table, and the electronic signature are data supplied to a memory of the authentication device,
  In the authentication device, first authentication by the electronic signature is performed,
  The plurality of partial content data is data in which partial content data to be read from among the plurality of partial content data is sequentially supplied to the memory of the authentication device during execution of the content data,
  In the authentication apparatus, a secondary digest value corresponding to the group is calculated from a group including a primary digest value corresponding to the supplied partial content data included in the primary digest table, and the calculated secondary By comparing the digest value with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the supplied partial content data, the validity of the content data is verified. Second authenticated,
  In the authentication apparatus, a primary digest value of the partial content data is calculated from the supplied partial content data, and the primary digest value corresponding to the calculated primary digest value and the supplied partial content data is calculated. A storage medium in which the validity of the content data is third-authenticated by collating with a primary digest value included in a table.   An authentication system for authenticating content data,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature generated using the secondary digest value are stored;
  First authentication means for performing authentication by the electronic signature;
  Designation means for sequentially designating partial content data to be read from among the plurality of partial content data during execution of the content data;
  First calculation means for calculating a secondary digest value corresponding to the group from a group including a primary digest value corresponding to the designated partial content data included in the primary digest table;
  The secondary digest value calculated in the first calculation step is collated with the secondary digest value included in the secondary digest table corresponding to the group including the primary digest value corresponding to the designated partial content data. A second authenticating means for authenticating the validity of the content data;
  Second calculating means for calculating a primary digest value of the partial content data from the specified partial content data;
  The validity of the content data is verified by comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data and included in the primary digest table. An authentication system comprising: third authentication means for authenticating   A method used in an authentication apparatus for authenticating content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature for authenticating the validity of the digest table are stored;
  A first authentication step of authenticating a digest table using the electronic signature; a designation step of designating partial content data to be read out of the plurality of partial content data by random access;
  A first calculation step of calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A second authentication step for authenticating the sex;
  A second calculation step of calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. A third authentication step of authenticating.   30. The authentication according to claim 29, further comprising a read step of reading a group including a primary digest value corresponding to the designated partial content data from the storage unit to the memory of the authentication device before the first calculation step. Method.   The authentication according to claim 29 or 30, wherein the process based on the partial content data designated by the designation step is executed on the condition that the validity is authenticated by the second authentication step and the third authentication step. Method.   32. The authentication method according to claim 29, wherein in the designation step, partial content data to be used next is designated as needed in accordance with execution of processing based on the content data.   The authentication method according to any one of claims 29 to 32, wherein the process based on the content data is executed on the condition that the validity is authenticated by the first authentication step.   The first authentication step is performed after the authentication device and the storage unit are accessible, and before the second authentication step and the third authentication step are performed. An authentication method according to any one of the above.   30. The hash function for calculating a primary digest value from the partial content data and the hash function for calculating a secondary digest value from the first digest table are the same. 34. The authentication method according to any one of 34.   The electronic signature is generated based on a digest value corresponding to a plurality of secondary digest values included in a second digest table, and a hash function for calculating the digest value is obtained from the partial content data using a primary digest value. 36. The authentication method according to any one of claims 29 to 35, wherein a security level is higher than that of a hash function for calculating.   The hash function for calculating the secondary digest value from the first digest table has a smaller processing amount for calculating the digest value than the hash function for calculating the primary digest value from the partial content data. The authentication method according to any one of claims 29 to 34, wherein:   An authentication device for authenticating content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature for authenticating the validity of the digest table are stored;
  First authentication means for authenticating the validity of a digest table using the electronic signature; designation means for designating partial content data to be read out of the plurality of partial content data by random access;
  First calculation means for calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A second authentication means for authenticating the sex;
  Second calculation means for calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication apparatus comprising: third authentication means for authenticating.   An authentication processing program executed in a computer of an authentication apparatus that authenticates content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature for authenticating the validity of the digest table are stored;
  A first authentication step of authenticating a digest table using the electronic signature; a designation step of designating partial content data to be read out of the plurality of partial content data by random access;
  A first calculation step of calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A second authentication step for authenticating the sex;
  A second calculation step of calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication processing program for causing the computer to execute a third authentication step for authentication.   A computer-readable storage medium storing a data structure used in an authentication device that authenticates content data using a digest table including a digest value,
  The data structure is
    The content data;
    A first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data;
    A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the plurality of partial content data;
    Including an electronic signature for authenticating the validity of the digest table,
  The first digest table, the second digest table, and the electronic signature are data supplied to a memory of the authentication device,
  In the authentication device, the validity of the digest table is first authenticated using the supplied electronic signature,
  The plurality of partial content data is data in which partial content data to be read out of the plurality of partial content data is supplied to the memory of the authentication device by random access,
  In the authentication apparatus, a secondary digest value of a group corresponding to the supplied partial content data is calculated using a digest value of the primary digest table, and the calculated secondary digest value and the secondary digest value are calculated. The validity of the content data is second-authenticated by collating with a secondary digest value of the group corresponding to the supplied partial content data in the table,
  In the authentication device, a primary digest value of the partial content data is calculated using the supplied partial content data, the calculated primary digest value, and the supplied portion in the primary digest table. A storage medium in which the validity of the content data is third-authenticated by collating with a primary digest value corresponding to the content data.   An authentication system for authenticating content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including a secondary digest value calculated for each corresponding group of primary digest values, and an electronic signature for authenticating the validity of the digest table are stored;
  First authentication means for authenticating the validity of a digest table using the electronic signature; designation means for designating partial content data to be read out of the plurality of partial content data by random access;
  First calculation means for calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A second authentication means for authenticating the sex;
  Second calculation means for calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication system comprising third authentication means for authentication.   A method used in an authentication device for authenticating content data using a digest table including a digest value, wherein the storage means accessible by the authentication device includes the content data and a plurality of parts constituting the content data A first digest table including primary digest values corresponding to content data and a second digest table including secondary digest values calculated for each group of primary digest values corresponding to the plurality of partial content data are stored. Has been
  A designation step of designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  A first calculation step of calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication step for authenticating the sex;
  A second calculation step of calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. A second authentication step of authenticating.   43. The authentication according to claim 42, further comprising a read step of reading a group including a primary digest value corresponding to the designated partial content data from the storage unit to the memory of the authentication device before the first calculation step. Method.   44. The authentication according to claim 42 or 43, wherein a process based on the partial content data designated by the designation step is executed on condition that the validity has been authenticated by the second authentication step and the third authentication step. Method.   45. The authentication method according to any one of claims 42 to 44, wherein in the designation step, partial content data to be used next is designated as needed with execution of processing based on the content data.   43. A hash function for calculating a primary digest value from the partial content data and a hash function for calculating a secondary digest value from the first digest table are the same. 45. The authentication method according to any one of 45.   The hash function for calculating the secondary digest value from the first digest table has a smaller processing amount for calculating the digest value than the hash function for calculating the primary digest value from the partial content data. 46. The authentication method according to any one of claims 42 to 45, wherein:   An authentication device for authenticating content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including secondary digest values calculated for each corresponding group of primary digest values is stored;
  Designating means for designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  First calculation means for calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated by the first calculation means with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication means for authenticating the sex;
  Second calculation means for calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated by the second calculation means with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication device comprising: a second authentication unit for authenticating.   An authentication processing program executed in a computer of an authentication apparatus that authenticates content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including secondary digest values calculated for each corresponding group of primary digest values is stored;
  A designation step of designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  A first calculation step of calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication step for authenticating the sex;
  A second calculation step of calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication processing program for causing the computer to execute a second authentication step for authentication.   A computer-readable storage medium storing a data structure used in an authentication device that authenticates content data using a digest table including a digest value,
  The data structure is
    The content data;
    A first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data;
    A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the plurality of partial content data,
  The plurality of partial content data is data supplied to the memory of the authentication device by random access during execution of the content data, from among the plurality of partial content data.
  In the authentication apparatus, a secondary digest value of a group corresponding to the supplied partial content data is calculated using a digest value of the primary digest table, and the calculated secondary digest value and the secondary digest value are calculated. The validity of the content data is first authenticated by collating with a secondary digest value of a group corresponding to the supplied partial content data in the table,
  In the authentication device, a primary digest value of the partial content data is calculated using the supplied partial content data, the calculated primary digest value, and the supplied portion in the primary digest table. A storage medium in which the validity of the content data is second-authenticated by collating with a primary digest value corresponding to the content data.   An authentication system for authenticating content data using a digest table including a digest value,
  The storage means accessible by the authentication device includes the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial content data. A second digest table including secondary digest values calculated for each corresponding group of primary digest values is stored;
  Designating means for designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  First calculation means for calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated by the first calculation means with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication means for authenticating the sex;
  Second calculation means for calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated by the second calculation means with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication system comprising: a second authentication means for authenticating.   A method used in an authentication apparatus that authenticates a digest table using an electronic signature and authenticates content data using a digest table, wherein the storage device accessible by the authentication apparatus includes at least the content data A first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and a secondary calculated for each group of primary digest values corresponding to the plurality of partial content data. A second digest table including digest values is stored,
  A designation step of designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  A first calculation step of calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication step for authenticating the sex;
  A second calculation step of calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. A second authentication step of authenticating.   53. The authentication according to claim 52, further comprising a reading step of reading a group including a primary digest value corresponding to the designated partial content data from the storage unit to the memory of the authentication device before the first calculation step. Method.   54. The authentication according to claim 52 or 53, wherein a process based on the partial content data designated by the designation step is executed on condition that the validity is authenticated by the second authentication step and the third authentication step. Method.   55. The authentication method according to any one of claims 52 to 54, wherein in the designation step, partial content data to be used next is designated as needed in accordance with execution of processing based on the content data.   53. The hash function for calculating a primary digest value from the partial content data and the hash function for calculating a secondary digest value from the first digest table are the same. 55. The authentication method according to any one of 55.   The hash function for calculating the secondary digest value from the first digest table has a smaller processing amount for calculating the digest value than the hash function for calculating the primary digest value from the partial content data. The authentication method according to any one of claims 52 to 55, wherein:   An authentication device that authenticates a digest table using an electronic signature and authenticates content data using the digest table,
  The storage means accessible by the authentication apparatus includes at least the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial contents. A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the data;
  Designating means for designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  First calculation means for calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated by the first calculation means with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication means for authenticating the sex;
  Second calculation means for calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated by the second calculation means with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication device comprising: a second authentication unit for authenticating.   An authentication processing program executed in a computer of an authentication device that authenticates a digest table using an electronic signature and authenticates content data using the digest table,
  The storage means accessible by the authentication apparatus includes at least the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial contents. A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the data;
  A designation step of designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  A first calculation step of calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated in the first calculation step with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication step for authenticating the sex;
  A second calculation step of calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated in the second calculation step with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication processing program for causing the computer to execute a second authentication step for authentication.   A computer-readable storage medium that stores a data structure used in an authentication device that authenticates a digest table using an electronic signature and authenticates content data using the digest table,
  The data structure is at least
    The content data;
    A first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data;
    A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the plurality of partial content data,
  The plurality of partial content data is data supplied to the memory of the authentication device by random access during execution of the content data, from among the plurality of partial content data.
  In the authentication apparatus, a secondary digest value of a group corresponding to the supplied partial content data is calculated using a digest value of the primary digest table, and the calculated secondary digest value and the secondary digest value are calculated. The validity of the content data is first authenticated by collating with a secondary digest value of a group corresponding to the supplied partial content data in the table,
  In the authentication device, a primary digest value of the partial content data is calculated using the supplied partial content data, the calculated primary digest value, and the supplied portion in the primary digest table. A storage medium in which the validity of the content data is second-authenticated by collating with a primary digest value corresponding to the content data.   An authentication system that authenticates a digest table using an electronic signature and authenticates content data using the digest table,
  The storage means accessible by the authentication apparatus includes at least the content data, a first digest table including primary digest values corresponding to a plurality of partial content data constituting the content data, and the plurality of partial contents. A second digest table including secondary digest values calculated for each group of primary digest values corresponding to the data;
  Designating means for designating partial content data to be read out of the plurality of partial content data by random access during execution of the content data;
  First calculation means for calculating a secondary digest value of a group corresponding to the designated partial content data using a digest value of the primary digest table;
  By verifying the secondary digest value calculated by the first calculation means with the secondary digest value of the group corresponding to the designated partial content data in the secondary digest table, the content data is validated. A first authentication means for authenticating the sex;
  Second calculation means for calculating a primary digest value of the partial content data using the designated partial content data;
  By comparing the primary digest value calculated by the second calculation means with the primary digest value corresponding to the designated partial content data in the primary digest table, the validity of the content data is verified. An authentication system comprising: a second authentication means for authenticating.

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