JP3882460B2 - MEMORY DEVICE, DATA PROCESSING DEVICE, DATA PROCESSING SYSTEM, AND DATA PROCESSING METHOD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a memory device and a data processing device in which a memory card which is detachable from a device is used as a medium for recording audio data, for example., Data processing systemandData processingRegarding the method.
[0002]
[Prior art]
An electrically rewritable non-volatile memory called EEPROM (Electrically Erasable Programmable ROM) is composed of two transistors, so it occupies a large area per bit and is limited in increasing the degree of integration. was there. In order to solve this problem, a flash memory capable of realizing one bit with one transistor by the all-bit batch erasing method has been developed. A flash memory is expected to replace a recording medium such as a magnetic disk or an optical disk.
[0003]
There is also known a memory card in which a flash memory is configured to be detachable from a device. By using this memory card, it is possible to realize a digital audio recording / reproducing apparatus that uses a memory card in place of a conventional disc-shaped medium such as a CD (compact disc) or an MD (mini disc).
[0004]
Audio recorders that use memory cards as recording media perform digital recording / playback, so if you are using a compression method that can restore relatively high-quality data, you should be able to protect the copyright of the music that is recorded / played back. It needs to be protected. As one of the methods, there is a method of making a memory card other than a genuine memory card unusable by an encryption technique. That is, encryption can be decrypted by a combination of a genuine recorder and a genuine memory card. Further, not only copyright protection but also encryption technology may be employed because the confidentiality of information stored in a memory card is required.
[0005]
A conventional memory card does not have an encryption function in itself. Therefore, when data that requires confidentiality is to be recorded on the memory card, it is necessary to encrypt the data on the set side and record the encrypted data on the memory card. However, when the decryption key is stored on the memory card, confidentiality cannot be maintained. On the other hand, when the decryption key is kept in the set, the encrypted data cannot be decrypted to other than the set, and there is a problem that the compatibility of the memory card cannot be maintained. For example, a memory card recorded with your own set cannot be decrypted with another person's set. In order to solve this problem, it has been proposed that both the set and the memory card have an encryption function and perform mutual authentication to ensure confidentiality and card compatibility.
[0006]
In practice, data that does not require copyright protection may be recorded / reproduced on a memory card. For example, when recording a conversation, an audio compression method having a high compression rate is used even if the quality of the restored sound is relatively poor. In this case, copyright protection is unnecessary. Also, when a memory card is used as a medium for recording an image taken with an electronic still camera, a video camera, or the like, copyright protection is unnecessary. In general, a security-compatible memory card having an encryption function is more expensive and expensive than a memory card without the security card, that is, a conventional memory card. Therefore, it is expected that a memory card that supports security and a memory card that does not support security will be used depending on the necessity of copyright protection and confidentiality maintenance.
[0007]
When there are two types of sets and memory cards that are both security-compatible and non-compliant, first, the security function is activated, and security compliance and non-security compliance are determined depending on whether normal operation or error occurs. There was a need. In another method, the shape of the memory card is made different depending on the difference in function. For example, a memory card having a security function is discriminated based on the presence or absence of a notch so that it cannot be attached to a lower-level device using a non-security compatible memory card.
[0008]
[Problems to be solved by the invention]
When deciding whether or not to have a security function, the method of actually operating the security function is an operation that is wasted if an error occurs, and a delay occurs due to the useless operation, and a comfortable operation for the user. There is a problem that cannot be called the environment. Also, the method of distinguishing by shape unambiguously determines the correspondence between the device and the memory card. For example, a memory card having a security function does not exhibit the security function, but eliminates the possibility of being used by lower-level devices. There is a problem. That is, when a security non-compliant set already exists, it is desirable that a security compatible memory card can be used with the existing set. For example, it is desirable that an image taken by a handy movie that is not compatible with security (camera-integrated recording / reproducing device) can be recorded on a security-compatible memory card and reproduced from the memory card. In this case, the encryption function is not used.
[0009]
Accordingly, an object of the present invention is to provide a memory device, a data processing device, and a method capable of determining whether or not the memory device has a new function different from the existing one without causing the above-described problems. is there.
[0010]
[Means for Solving the Problems]
  In order to solve the above-mentioned problems,ThisThe invention of this invention has a data processing device having an encryption function and an encryption function.ShiIn a detachable memory device that can be recorded or reproduced in any of the data processing devices that are not,
  Non-volatile memory;
  A circuit having an encryption function;
  An interface means arranged for data communication between the data processing device and the nonvolatile memory,
  Does the storage area of the non-volatile memory have an encryption function in the predetermined storage area that is first read by the data processing device when used?or notRecord identification informationAnd
  When connected to a data processing device having an encryption function, after the identification information is read, an authentication operation is performed, and after the authentication is established, a write operation or a read operation to the nonvolatile memory is performed,
  When connected to a data processing device that does not have an encryption function, after the identification information is read, a write operation or a read operation to the nonvolatile memory is performed without performing an authentication operation.This is a memory device.
[0011]
  ThisThe present invention relates to a data processing device that is detachable and uses a memory device including a nonvolatile memory as a recording medium.
  A circuit having an encryption function;
  An interface means for communicating with the memory device mounted in the mounting unit;
  On the mounting partWhether a memory device having an encryption function and a memory device having no encryption function have the encryption function of the memory device in the storage area of the nonvolatile memory when the memory device is mounted First, a predetermined storage area in which identification information indicating whether or not is stored is read,Whether the memory device mounted in the mounting unit has an encryption function based on the identification information in the predetermined storage area that is read first when using the mounted memory deviceor notDecide
  When connected to a memory device having an encryption function, an authentication operation is performed after the identification information is read out, and a nonvolatile memory is used by using a circuit having an encryption function of the data processing device after the authentication is established A write or read operation is performed on
  When connected to a memory device that does not have an encryption function, a notice is given that the memory device cannot be used.This is a data processing apparatus characterized by the above.
[0012]
  ThisThe invention is detachable from the data processing device by the data processing device.With non-volatile memoryIn a data processing method for writing or reading information to or from a memory device,
  In the mounting part of the data processorWhether a memory device having an encryption function and a memory device having no encryption function have the encryption function of the memory device in the storage area of the nonvolatile memory when the memory device is mounted A memory device attached to the attachment unit according to the identification information in the predetermined storage area that is read first when a predetermined storage area in which identification information indicating whether or not is stored is first read and used. Decide whether or not has encryption function,
  When connected to a memory device having an encryption function, an authentication operation is performed after the identification information is read out, and a nonvolatile memory is used by using a circuit having an encryption function of the data processing device after the authentication is established A write or read operation is performed on
  When connected to a memory device that does not have an encryption function, a notice is given that the memory device cannot be used.This is a data processing method characterized by the above.
[0013]
In the present invention, when the memory device is used, identification information as to whether or not it has a new function is recorded in the area of the nonvolatile memory that is read first. The data processing device can immediately set whether or not the memory device has a new function from this identification information.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows the overall configuration of an embodiment of the present invention. This embodiment is a digital audio signal recorder (recording and reproducing device) that uses a removable memory card as a recording medium. In FIG. 1, reference numeral 1 surrounded by a broken line indicates a recorder as a set, and reference numeral 40 indicates a memory card which can be attached to and detached from the recorder. The present invention can also be applied to recording / reproduction of moving image data, still image data, etc. in addition to digital audio signals.
[0015]
The recorder 1 includes a CPU 2, a security block connected to the CPU 2 via a bus, operation buttons 4, and a display device 5. The security block 3 includes a DES (Data Encryption Standard) encryption circuit. Data such as a recording command and a playback command generated in response to a user operation from the operation button 4 is given to the CPU 2 via the bus. Various information, the operating state of the recorder 1 and the like are displayed on the display device 5. Reference numeral 6 denotes an audio interface provided between the external input / output and the internal audio encoder / decoder 7.
[0016]
As will be described later, the memory card 40 includes a flash memory (nonvolatile memory) 42, a security block 52 including a DES encryption circuit, a communication interface, a register, and the like on a single chip. The memory card 40 is detachable from the recorder 1. In this embodiment, the recorder 1 can use a memory card that does not have an encryption function, that is, a memory card that does not have a security block.
[0017]
The audio encoder / decoder 7 encodes the digital audio signal with high efficiency and decodes the highly efficient encoded data. As a high-efficiency encoding method, an improved ATRAC (Adaptive Transform Acoustic Coding) adopted in a mini-disc (denoted as ATRAC3) can be used. In ATRAC3, 1-sample 16-bit audio data sampled at 44.1 kHz is processed. The minimum data unit when processing audio data with ATRAC3 is a sound unit SU. One SU is 1024 samples (1024 × 16 bits × 2 channels) compressed to several hundred bytes, and is about 2.3 milliseconds in time. Audio data is compressed to about 1/10 by ATRAC3. As is the case with the mini-disc, the sound quality deterioration due to compression / decompression processing is small due to the signal processing of ATRAC3.
[0018]
Analog audio signals 8 such as MD (mini disc) playback output, tuner output, tape playback output, etc. are converted into digital audio signals by an A / D converter 9, and the digital audio signals are supplied to the audio interface 6. The digital input 10 is MD or CD (compact disc) playback output, digital broadcasting, audio data distributed over a network, and the like. A digital input 10 is supplied to the audio interface 6. The digital input 10 is transmitted via an optical cable, for example. In the audio interface 6, input selection processing is performed, and the selected input digital audio signal is supplied to the audio encoder / decoder 7.
[0019]
The encoded data from the audio encoder / decoder 7 is encrypted in the security block 3. The security block 3 is provided for protecting the copyright of the content (here, digital audio signal). The security block 3 of the recorder 1 has a plurality of master keys and a unique storage key for each device. Further, when a memory card 40 having a random number generation circuit and incorporating the security block 52 is attached, authentication is performed to confirm whether the attached one is authentic, and if it can be correctly authenticated, the session key is shared. be able to.
[0020]
The encrypted audio data from the security block 3 is supplied to the CPU 2. The CPU 2 performs communication via the memory interface 11 with the memory card 40 mounted on the attaching / detaching mechanism (not shown), and writes the encrypted data in the flash memory 42 of the memory card 40. Serial communication is performed between the CPU 2 and the memory card 40 by the memory interface 11.
[0021]
The encrypted audio data read from the memory card 40 by the CPU 2 and the memory interface 11 is decrypted by the security block 3 and decrypted by the audio encoder / decoder 7. The output of the audio encoder / decoder 7 is supplied to the D / A converter 12 via the audio interface 6 and converted into the analog audio output 13. Audio data from the audio encoder / decoder 7 and decoded data from the security block 3 are output as digital outputs 14 and 15 through the interface 6.
[0022]
FIG. 2 shows the configuration of the memory card 40. The memory card 40 has a control block 41 and a flash memory 42 configured as a one-chip IC. The bidirectional serial interface (memory interface 11) between the CPU 2 of the recorder 1 and the memory card 40 is composed of 10 lines. The four main lines are a clock line SCK for transmitting a clock during data transmission, a status line SBS for transmitting status, a data line DIO for transmitting data, and an interrupt line INT. In addition, two GND lines and two VCC lines are provided as power supply lines. Two lines Reserv are undefined lines.
[0023]
The clock line SCK is a line for transmitting a clock synchronized with data. The status line SBS is a line for transmitting a signal representing the status of the memory card 40. The data line DIO is a line for inputting and outputting commands and encrypted audio data. The interrupt line INT is a line for transmitting an interrupt signal for requesting an interrupt from the memory card 40 to the CPU 2 of the recorder 1. An interrupt signal is generated when the memory card 40 is inserted. However, in this embodiment, since the interrupt signal is transmitted through the data line DIO, the interrupt line INT is grounded and not used.
[0024]
The serial / parallel conversion / parallel / serial conversion / interface block (abbreviated as S / P, P / S, IF block) 43 of the control block 41 is a memory interface 11 of the recorder 1 connected via the plurality of lines described above. And the control block 41. The S / P, P / S, and IF block 43 converts the serial data received from the recorder 1 into parallel data, fetches it into the control block 41, converts the parallel data from the control block 41 into serial data, and sends it to the recorder 1. send. The S / P, P / S, and IF block 43, when receiving a command and data transmitted via the data line DIO, encrypts the command and data for normal access to the flash memory 42, and encryption. Separate necessary commands and data.
[0025]
That is, in the format transmitted via the data line DIO, the command is transmitted first, and then the data is transmitted. The S / P, P / S, and IF block 43 determines whether the command and data necessary for normal access or the command and data necessary for encryption are viewed from the command code. In accordance with the determination result, a command necessary for normal access is stored in the command register 44 and data is stored in the page buffer 45 and the write register 46. An error correction encoding circuit 47 is provided in association with the write register 46. For the data temporarily stored in the page buffer 45, the error correction encoding circuit 47 generates a redundant code of the error correction code.
[0026]
Output data of the command register 44, page buffer 45, write register 46, and error correction encoding circuit 47 is supplied to a flash memory interface and a sequencer (memory I / F, abbreviated as sequencer) 51. The memory IF / sequencer 51 is an interface between the control block 41 and the flash memory 42 and controls data exchange between the two. Data is written to the flash memory 42 via the memory IF and the sequencer 51.
[0027]
Data read from the flash memory 42 is supplied to the page buffer 45, read register 48, and error correction circuit 49 via the memory IF and sequencer 51. Data stored in the page buffer 45 is error-corrected by the error correction circuit 49. The error-corrected output of the page buffer 45 and the output of the read register 48 are supplied to the S / P, P / S, and IF block 43 and supplied to the CPU 2 of the recorder 1 via the serial interface described above.
[0028]
For copyright protection, content written to the flash memory 42 by the security IC 40 of the recorder 1 and the security block 52 of the memory card 40 (audio data compressed by ATRAC3, hereinafter referred to as ATRAC3 data) is encrypted. Is done. The security block 52 includes a buffer memory 53, a DES encryption circuit 54, a nonvolatile memory 55, and the like.
[0029]
Reference numeral 50 denotes a configuration ROM that stores version information of the memory card 40, various attribute information, and the like. Further, the memory card 40 is provided with an erroneous erasure prevention switch 60 that can be operated by the user as needed. When the switch 60 is in the erase prohibition connection state, even if a command for instructing to erase the flash memory 42 is sent from the recorder 1 side, the erase of the flash memory 42 is prohibited. Further, 61 is an oscillator that generates a clock that is a timing reference for processing of the memory card 40.
[0030]
The security block 52 of the memory card 40 has a plurality of authentication keys and a unique storage key for each memory card. The non-volatile memory 55 stores a key necessary for encryption and is not visible from the outside. For example, the storage key is stored in the nonvolatile memory 55. Further, it has a random number generation circuit, can authenticate correctly with a dedicated recorder (meaning that a certain data format etc. is used in the same system), and can share a session key. The content key for encrypting the ATRAC3 data is encrypted with the session key and transmitted between the recorder 1 and the memory card 40. Similar to the security block 52 of the memory card 40, the security block 3 of the recorder 1 has a set-specific storage key. When moving the encrypted content, the content key is redone using the storage key.
[0031]
FIG. 3 shows a memory card 40 'that does not have an encryption function (ie, does not support security). Compared with the memory card 40 shown in FIG. 2 and described above, the security block 52 is not connected to the S / P, P / S, and IF block 43. Regarding other configurations, the memory cards 40 and 40 'are the same. The shape and size of the memory cards 40 and 40 'are also the same. Since the recorder 1 shown in FIG. 1 is security-compatible, it performs mutual authentication with a memory card, key communication, and the like. If the memory card 40 ′ shown in FIG. 3 that does not support security is inserted, the recorder 1 determines that the memory card 40 ′ is incompatible with security and the memory card 40 ′ cannot be used.
[0032]
Several methods can be used for the recorder 1 to determine the type of the memory card. In one method, when a key is transmitted to authenticate when a memory card is inserted, a normal response cannot be received from the memory card 40 ′, and a time-out is determined in the recorder 1, and as a result. It can be determined that the memory card is not compatible with security. In another method, when a memory card is inserted, identification information corresponding to security / non-correspondence is recorded in a memory card area (boot area) that is first read into the recorder 1, and based on this identification information. The recorder 1 can determine the type of memory card.
[0033]
In addition to the recorder 1 shown in FIG. 1, there is a device that uses a memory card 40 'that does not support security. For example, a memory card 40 'can be used for a digital handy movie having a function of recording an image taken by a CCD camera on a memory card and reproducing the taken image from the memory card. Normally, such a digital handy movie cannot use a memory card 40 that supports security. As will be described later, in one embodiment of the present invention, in order to increase the compatibility of the memory card 40, a set such as a digital handy movie that does not support security can be recorded and reproduced using the memory card 40. A memory card 40 is configured. That is, as described above, the S / P, P / S, and IF block 43 have a function of separating commands and data for writing / reading from the flash memory 42 and commands and data necessary for the security block. Have.
[0034]
The above-described embodiment of the present invention will be described in more detail. FIG. 4 shows a file system processing hierarchy of a computer system using a memory card as a storage medium. As the file system processing hierarchy, the application processing layer is the highest level, and below this, the file management processing layer, logical address management layer, physical address management layer, and flash memory access are sequentially arranged. In this hierarchical structure, the file management processing layer is the FAT file system. The physical address is assigned to each block of the flash memory, and the correspondence between the block and the physical address is unchanged. The logical address is an address logically handled by the file management processing layer.
[0035]
FIG. 5 shows an example of a physical configuration of data in the flash memory 42 in the memory card 40. In the flash memory 42, a data unit called a segment is divided into a predetermined number of blocks (fixed length), and one block is divided into a predetermined number of pages (fixed length). In the flash memory 42, erasing is collectively performed in units of blocks, and writing and reading are performed in units of pages. Each block and each page have the same size, and one block is composed of page 0 to page m. One block has a capacity of, for example, 8 KB (K bytes) bytes or 16 KB, and one page has a capacity of 512 B. The entire flash memory 42 has 4 MB (512 blocks) and 8 MB (1024 blocks) when 1 block = 8 KB, and 16 MB (1024 blocks), 32 MB (2048 blocks), 64 MB (1 block = 16 KB). 4096 blocks).
[0036]
One page consists of a 512-byte data part and a 16-byte redundant part. The first 3 bytes of the redundant portion are an overwrite portion that is rewritten in accordance with the data update. The block status, page status, and update status are recorded in each of the 3 bytes in order from the top. The contents of the remaining 13 bytes of the redundant part are basically fixed according to the contents of the data part. 13 bytes are composed of a management flag (1 byte), a logical address (2 bytes), a format reserve area (5 bytes), distributed information ECC (2 bytes), and data ECC (3 bytes). The distributed information ECC is redundant data for error correction with respect to the management flag, logical address, and format reserve, and the data ECC is redundant data for error correction with respect to 512-byte data.
[0037]
As a management flag, a system flag (its value is 1: user block, 0: boot block), conversion table flag (1: invalid, 0: table block), copy prohibition designation (1: OK, 0: NG), access permission Each flag (1: free, 0: read protect) is recorded.
[0038]
The first two blocks 0 and 1 are boot blocks. Block 1 is for backup in which the same data as block 0 is written. The boot block is a head block of valid blocks in the card, and is a block that is first accessed when a memory card is loaded into the device. The remaining blocks are user blocks. A header, system entry, and boot & attribute information are stored in the first page 0 of the boot block. Page 1 stores use-prohibited block data. Page 2 stores CIS (Card Information Structure) / IDI (Identify Drive Information).
[0039]
FIG. 6 shows the format of the boot block. The boot block header (368 bytes) records the boot block ID, the format version, and the number of valid entries in the boot block. In the system entry (48 bytes), the start position of the prohibited block data, its data size, data type, CIS / IDI data start position, its data size, and data type are recorded.
[0040]
FIG. 7 shows the boot & attribute information (968 bytes) in detail. Boot & attribute information includes memory card class, type (read only, read and write, hybrid of both types, etc.), block size, number of blocks, total number of blocks, security support, and card manufacturing The recorded data (manufacturing date, etc.) is recorded. The set can determine whether or not the attached memory card is security-compatible based on the identification information (1 byte) indicating whether or not the security is compatible. In FIG. 7, information with (* 1) is an item to be read by the set side and checked at the time of mounting, and information with (* 2) is an item for setting information on manufacturing and quality control. is there.
[0041]
In the flash memory, the data is rewritten, the insulating film is deteriorated, and the number of rewrites is limited. Therefore, it is necessary to prevent repeated and concentrated access to a certain storage area (block). Therefore, when rewriting the data of a certain logical address stored at a certain physical address, the flash memory file system does not rewrite the updated data to the same block, but rewrites the unused block. The updated data is written. As a result, the correspondence between the logical address and the physical address before the data update changes after the update. By performing such processing (referred to as swap processing), it is possible to prevent repeated and concentrated access to the same block, and to extend the life of the flash memory.
[0042]
Since the logical address is attached to the data once written to the block, even if the block in which the pre-update data and the post-update data are moved moves, the same address can be seen from the FAT. Subsequent access can be performed appropriately. Since the correspondence relationship between the logical address and the physical address is changed by the swap processing, a logical-physical address conversion table indicating the correspondence between the two is required. By referring to this table, the physical address corresponding to the logical address specified by the FAT is specified, and the block indicated by the specified physical address can be accessed.
[0043]
The logical-physical address conversion table is stored on the memory by the CPU 2. If the RAM capacity is small, it can be stored in the flash memory. This table is generally a table in which physical addresses (2 bytes) are associated with logical addresses (2 bytes) arranged in ascending order. Since the maximum capacity of the flash memory is 128 MB (8192 blocks), 8192 addresses can be represented by 2 bytes. The logical-physical address conversion table is managed for each segment, and its size increases according to the capacity of the flash memory. For example, when the capacity of the flash memory is 8 MB (2 segments), two pages are used for the logical-physical address conversion table for each of the two segments. When the logical-physical address conversion table is stored in the flash memory, whether or not the block is a block in which the logical-physical address conversion table is stored according to a predetermined 1 bit of the management flag in the redundant portion of each page described above. Is instructed.
[0044]
The memory card described above can be used by the FAT file system of a personal computer, as with a disk-shaped recording medium. Although not shown in FIG. 5, an IPL area, a FAT area, and a root directory area are provided on the flash memory. In the IPL area, an address where a program to be loaded into the memory of the recorder first is written and various information of the memory are written. In the FAT area, related items of blocks (clusters) are written. The FAT defines values indicating an unused block, the next block number, a bad block, and the last block. Furthermore, directory entries (file attributes, update date, start cluster, file size, etc.) are written in the root directory area.
[0045]
Further, in this embodiment, file management information (track information management file) is defined for music files, separately from the file management system defined by the format of the memory card 40 described above. The track information management file is recorded on the flash memory 42 using the user block of the memory card 40. Thereby, even if the FAT on the memory card 40 is broken, the file can be repaired.
[0046]
The track information management file is created by the CPU 2. For example, when the power is first turned on, it is determined whether or not the memory card 40 is attached. When the memory card is attached, the boot block of the flash memory 42 is read into the CPU 2. Based on the identification information in the boot block, it is determined whether the inserted memory card is compatible with security or not. If it is determined that security is supported, an authentication operation is performed. Data read from other memory cards 40 is stored in a memory (not shown) managed by the CPU 2. Even for a memory card that the user purchases for the first time, FAT and a root directory are written in the flash memory 42 at the time of shipment. The track information management file is created when recording is performed. When the authentication is established, the recorder 1 records / reproduces the encrypted ATRAC3 data file.
[0047]
At the time of recording, a recording command generated by pressing the recording button with the operation button 4 is given to the CPU 2. The input audio data is compressed by the encoder / decoder 7, and the ATRAC3 data from the encoder / decoder 7 is encrypted by the security block 3. The CPU 2 records the encrypted ATRAC3 data in the flash memory 42 of the memory card 40. After this recording, the FAT and track information management file are updated. Each time a file is updated, specifically, recording of audio data is started and each time recording is completed, the FAT and track information management file are rewritten on a memory (not shown) controlled by the CPU 2. When the memory card 40 is removed or the power is turned off, the final FAT and track information management file is stored from the memory onto the flash memory 42 of the memory card 40. In this case, the FAT and track information management file on the flash memory 42 may be rewritten every time recording of audio data starts and ends. Even when editing is performed, the contents of the track information management file are updated.
[0048]
The security protection function in the above-described embodiment of the present invention will be further described. First, the key relationship in the content will be described with reference to FIG. On the flash memory 42 of the memory card 40, as shown in FIG. 8A, a key area 101 is provided, and a content key CK created for each content (track (song) of encrypted audio data) in the key area 101. Is encrypted with a storage key Kstm unique to the memory card and stored. Encryption is written as DES, and when the content key CK is encrypted with the storage key Kstm, it is written as DES (Kstm, CK). In this embodiment, the encrypted value is handled with a 64-bit length obtained by adding an error detection CRC (8 bits) to 56 bits.
[0049]
A part data area 102 is defined in the content track, and a part key PK is recorded for each part. Each part is a set of 16 Kbyte blocks 103. Each block has a block seed BK. SEED and initial vector INV are recorded. The part key PK is used in pairs with the content key CK in order to create a block key BK for encrypting the content. That is, BK = DES (CK (+) PK, BK SEED) (56 bits + 8 bits). (+) Represents exclusive OR. The initial vector INV is an initial value for block encryption and decryption.
[0050]
FIG. 8B shows content in the recorder 1. The content key CK for each content is decrypted in the key area 111, re-encrypted with the storage key Kstd unique to the recorder 1, and held. That is, decryption is expressed as IDES (Kstm, CK) (56 bits + 8 bits), and re-encryption is expressed as DES (Kstd, CK) (56 bits + 8 bits). A part key PK for creating a block key BK is recorded for each part data area 112 constituting the content. Each of the blocks 113 constituting the part has a block seed BK. SEED and initial vector INV are recorded. As on the memory card, the block key BK is BK = DES (CK (+) PK, BK SEED) (56 bits + 8 bits).
[0051]
FIG. 9 is a simplified block diagram for explaining the flow of encryption processing at the time of recording. The parts corresponding to those in FIG. Unnecessary components are omitted. Sek is a session key shared between the recorder 1 and the memory card 40 when authentication is established. A CD 10 ′ is shown as the source of the digital audio input 10.
[0052]
When the memory card 40 is attached to the recorder 1, whether or not the attached memory card is compatible with security is determined by the identification information in the boot area. If it is determined that it is security-compatible, the recorder 1 and the memory card 40 authenticate whether they are authentic.
[0053]
FIG. 10 shows the encryption processing between the set (recorder 1) and the memory card 40 at the time of authentication. In the first step S 1, a random number Rm is generated by a random number generator in the security block 52 of the memory card 40 and transmitted together with the serial number ID of the memory card 40.
[0054]
In the recorder 1, the process of step S2 is performed. That is, Rm and ID are received, and an authentication key IKj is generated according to the relationship of IKj = MAC (MKj, ID). MKj is a plurality of master keys MK stored in the security block 3 of the recorder 1₀~ MK₃₁One master key selected from the list. The recorder 1 generates a random number Rd, and a message authenticator MAC with an authentication key._A(Message Authentication Code), that is, MAC (IKj, ID // Rm // Rd) is created. Here, A // B indicates a concatenation of A and B (m bits B are combined with n bits A followed by (n + m) bits). Then, the recorder 1 generates a random number Sd and Rd // Sd // MAC_A// Send j to the memory card 40.
[0055]
In step S3, the memory card 40 stores the data Rd // Sd // MAC._A// Receive j, find authentication key IKj in security block 52 from j, use authentication key IKj and Rd, Rm, ID_BCalculate Calculated MAC_BReceived by_AThe memory card 40 accepts the set (recorder) as correct. In step S4, the memory card 40 stores the MAC_C= MAC (IKj, Rm // Rd) is generated, and a random number Sm is generated. Thereafter, the memory card 40 stores the Sm // MAC._CIs transmitted to the recorder 1.
[0056]
In step S5, the recorder 1 performs Sm // MAC_CReceive. Recorder 1 uses IKj, Rm, and Rd for MAC_DCalculate Calculated MAC_DReceived by_CThe recorder 1 recognizes the memory card 40 as correct (ie, authenticates). At this stage, both the recorder 1 and the memory card 40 have the authentication key IKj and the random numbers Sd and Sm selected. In step S6, the recorder 1 designates MAC (IKj, Rm // Rd) as the session key Sek. Also on the memory card 40 side, MAC (IKj, Rm // Rd) is designated as the session key Sek. As described above, when mutual authentication is correctly performed, the session key Sek is shared by the recorder 1 and the memory card 40. The session key is generated every time authentication is established.
[0057]
FIG. 11 shows a key writing process when the recorder 1 records an audio file in the flash memory 42 of the memory card 40. Note that when the writing process is started, the session key Sek generation process is finished, and the recorder 1 and the memory card 40 share the session key Sek. In step S11, the recorder 1 generates a random number for each piece of content track data, and creates a content key CK corresponding to the random number. Next, in step S <b> 12, the recorder 1 encrypts the content key CK with the session key Sek, and transmits the encrypted DES (Sek, CK) to the memory card 40.
[0058]
In step S13, the memory card 40 receives this data and decrypts the content key CK with the session key. That is, IDES (Sek, DES (Sek, CK)) and decryption processing are written. In the next step S14, the memory card 40 re-encrypts the decrypted content key CK with the storage key Kstm of the memory card 40, and the re-encrypted content key DES (Kstm, CK) is transmitted to the recorder 1.
[0059]
In step S15, the recorder 1 places the re-encrypted content key in the key area 111 that manages the part data area 112, and the re-encrypted content key CK and the content are recorded in the flash memory of the memory card 40. The formatting process is performed as follows. For content encryption, as shown in FIG. 9, the exclusive OR or logical product of the content key CK and the part key PK is taken. As a result, a temporary key TMK is obtained. The temporary key TMK exists only in the security block 3 and is not accessible from the outside. A random number is generated at the head of each block 113, and this is generated as a block seed BK. SEED is stored in each part data area 112. Recorder 1 uses temporary key TMK to block seed BK SEED is encrypted and a block key BK is obtained. That is, BK = (CK (+) PK, BK SEED) relationship is obtained. The block key BK also exists only in the security block 3 and is not accessible from outside the security block 3.
[0060]
In step S <b> 16, the recorder 1 encrypts the data in the part data area 112 for each block using the block key BK, and transmits the encrypted data and the data in the key area 111 to the memory card 40. The memory card 40 records the encrypted data received from the recorder 1 and the data (header data) in the key area 111 in the flash memory 42 (step S17).
[0061]
FIG. 12 is a simplified block diagram for explaining the flow of processing when the recorder 1 reproduces an audio track stored in the flash memory 42 of the memory card 40. In the portion corresponding to FIG. Are denoted by the same reference numerals, and components that are not particularly necessary for explanation of encryption and decryption are omitted. FIG. 13 shows a decoding process when the audio track is reproduced from the flash memory 42 of the memory card 40 by the recorder 1 as in FIG. Even during playback, the mutual authentication is established, so that the session key Sek is shared between the recorder 1 and the memory card 40.
[0062]
In step S21, the recorder 1 reads the data from the memory card 40, thereby encrypting the content key CK encrypted with the storage key Kstm, that is, (DES (Kstm, CK)) and the encrypted content (the desired track). A parts data area 102) is obtained. Then, the recorder 1 passes the content key CK encrypted with the storage key Kstm to the memory card 40.
[0063]
In step S22, the memory card 40 decrypts the content key CK with the storage key Kstm (IDES (Kstm, DES (Kstm, CK)). Encrypt and send DES (Sek, CK) to the recorder 1.
[0064]
In step S24, the recorder 1 decrypts the content key with the session key Sek. In the next step S25, the recorder 1 recognizes the decrypted content key CK, part key PK, and block seed BK. A block key BK is created using SEED. In step S26, the recorder 1 decrypts each part data area 102 encrypted by the block key BK for each block. The decoded audio data is decoded by the audio encoder / decoder 7.
[0065]
Other than the above-described read operation and write operation, a command is transmitted in state 1, and data corresponding to the command is transmitted in state 2 thereafter. The serial interface between the recorder 1 and the memory card 40 is not limited to that described above, and various types can be used.
[0066]
The Syrian interface between the recorder 1 and the memory card 40 in one embodiment of the present invention will be described in more detail. As shown in FIG. 2, among the ten lines connecting the recorder 1 and the memory card 40, the main ones for signal transmission / reception are the clock line SCK, the status line SBS, and the data line DIO. .
[0067]
FIG. 14 shows the timing when data is read from the memory card 40. In a state other than the state 0 (initial state), a clock synchronized with the data transmitted through the clock line SCK is transmitted. When no data is transmitted / received between the recorder 1 and the memory card 40, the status line SBS is at a low level. This is state 0 (initial state). At timing t31, the recorder 1 sets the status line SBS to the high level and enters the state 1.
[0068]
The memory card 40 (S / P, P / S, IF block 43) detects the change from the state 0 to the state 1 due to the status line SBS being switched to the high level. In state 1, a read command is transmitted from the recorder 1 to the memory card 40 via the data line DIO, and the memory card 40 receives the read command. This read command is a protocol command called TPC (Serial Protocol Command) for serial interface. As will be described later, the contents of communication and the data length of subsequent data are specified by the protocol command.
[0069]
At the timing t32 when the command transmission is completed, the status line SBS is switched from the high level to the low level. As a result, transition from state 1 to state 2 occurs. In the state 2, the process instructed by the command received by the memory card 40, specifically, the process of reading the data at the address specified by the read command from the flash memory 42 is performed. While this processing is being performed, a busy signal (high level) is transmitted to the recorder 1 via the data line DIO.
[0070]
Then, at timing t33 when reading of data from the flash memory 42 is completed, the output of the busy signal is stopped, and a ready signal (low level) indicating that the recorder 1 is ready to send data from the memory card 40. Starts to output.
[0071]
By receiving the ready signal from the memory card 40, the recorder 1 knows that the process corresponding to the read command is ready, and switches the status line SBS to the high level at timing t34. That is, the state 2 changes to the state 3.
[0072]
In state 3, the memory card 40 outputs the data read to the page buffer 45 in state 2 to the recorder 1 through the data line DIO. At the timing t35 when the transfer of the read data is completed, the recorder 1 stops supplying the clock transmitted via the clock line SCK and switches the status line from the high level to the low level. Thereby, the state 3 is changed to the initial state (state 0).
[0073]
When a change occurs in the internal state of the memory card 40 and it is necessary to perform some kind of interrupt processing, the memory card 40 sends an interrupt signal indicating an interrupt to the data line DIO in the state 0 as shown at timing t36. To the recorder 1. When the signal is supplied from the memory card 40 via the data line DIO in the state 0, the recorder 1 is set so that the signal can be recognized as an interrupt signal. When the recorder 1 receives the interrupt signal, the recorder 1 performs necessary processing based on the interrupt signal.
[0074]
FIG. 15 is a timing chart when data is written to the flash memory 42 of the memory card 40. In the initial state (state 0), the clock SCK is not transmitted. At timing t41, the recorder 1 switches the status line SBS from the low level to the high level. Thereby, the state transits to the state 1 where the write command is transmitted via the data line DIO. In state 1, the memory card 40 prepares to obtain a command. The command is transmitted from the timing t41 to the memory card 40 via the data line DIO, and the memory card 40 acquires this write command.
[0075]
At timing t42 when the transmission of the write command is completed, the recorder 1 switches the status line SBS from the high level to the low level. As a result, transition from state 1 to state 2 occurs. In state 2, the recorder 1 transmits the write data to the memory card 40 via the data line DIO. In the memory card 40, the received write data is stored in the page buffer 45.
[0076]
At the timing t43 when the transmission of the write data is completed, the status line SBS is switched from the low level to the high level, and the state 2 is changed to the state 3. In the state 3, the memory card 40 performs a process of writing write data to the flash memory 42. In the state 3, the memory card 40 transmits a busy signal (high level) to the recorder 1 via the data line SBS. Since the recorder 1 transmits a write command and the current state is state 3, the recorder 1 determines that the signal transmitted from the memory card 40 is a status signal.
[0077]
When the write processing of the write data is completed in the memory card 40, the busy signal output is stopped and the ready signal (low level) is transmitted to the recorder 1 at the end timing t44. When receiving the ready signal, the recorder 1 determines that the writing process corresponding to the writing command is completed, stops transmission of the clock signal, and switches the status line SBS from the high level to the low level at timing t45. Thereby, the state 3 is returned to the state 0 (initial state).
[0078]
Further, in the state 0, when the recorder 1 receives a high level signal from the memory card 40 via the data line DIO, the recorder 1 recognizes this signal as an interrupt signal. Then, the recorder 1 performs necessary processing based on the received interrupt signal. For example, when the memory card 40 is removed from the recorder 1, the memory card 40 generates an interrupt signal.
[0079]
Other than the above-described read operation and write operation, a command is transmitted in state 1, and data corresponding to the command is transmitted in state 2 thereafter. The serial interface between the recorder 1 and the memory card 40 is not limited to that described above, and various types can be used.
[0080]
In one embodiment of the present invention, processing performed by a device that can use a memory card will be described in more detail with reference to FIG. When the device is turned on (step S200), it is determined in step S201 whether a memory card is inserted. If it is determined that a memory card is inserted, the boot block of the memory card is read (step S202).
[0081]
As described with reference to FIG. 7, the boot & attribute information of the boot block includes identification information as to whether or not security is supported. With reference to this identification information, it is determined whether the inserted memory card is compatible with security or not (step S203). If the memory card 40 is compatible with security, an authentication operation is performed in step S204, and content data is recorded / reproduced after the authentication is established (step S205).
[0082]
If it is determined in step S203 that the inserted memory card is a non-security compatible memory card 40 ', a notification that the inserted memory card 40' cannot be used is made in step S206. Notification is made by displaying a warning message on the display device 5. The notification may be performed by other methods such as voice.
[0083]
The processing described above is performed by a security-compatible device like the recorder 1. If the device does not support security, the process moves to step S207 after step S202 (reading of the boot block) as indicated by a broken line in FIG. In step S207, it is determined whether the inserted memory card is compatible with security or not. Regardless of whether the result of determination in step S207 is affirmative or negative, normal operations (writing, reading, erasing, etc.) can be performed on the memory card 40 'as shown in steps S208 and S209.
[0084]
In the embodiment described above, the function of the memory card is a security function, but the present invention is not limited to the security function. For example, the communication speed or data rate at the interface between the device and the memory card can be faster (high speed) than the existing speed (low speed). The present invention can be applied to the case where the memory card has a new function relating to this speed.
[0085]
FIG. 17 is a flowchart showing processing related to speed. In step S300, the power is turned on. In step S301, it is determined whether a memory card is inserted. In step S302, the boot block is read. Similar to the security function, the block block includes identification information indicating whether the memory card is compatible with high speed or not.
[0086]
If the identification information determines that the memory card is compatible with high speed, the communication speed or data rate between the device and the memory card is switched from low speed to high speed (step S304), and high speed operation is performed (step S305). If it is determined in step S303 that high speed is not supported, low speed operation is performed (step S306). When the device does not support high speed, as indicated by a broken line in FIG. 17, the low speed operation is performed without being affected by the result of the determination of whether it is high speed compatible (step S307) (steps S308 and S309).
[0087]
In the above description, the case where DES is used has been described. However, the security method is not limited to DES, and it is versatile to employ various encryption techniques.
[0088]
【The invention's effect】
According to this invention, as a removable memory device such as a memory card, even if a device with a new function and a device without it are mixed, the device instantly determines whether or not a new function is present at the time of mounting. can do. Therefore, unlike the method of determining the presence or absence of a new function depending on whether or not the device actually communicates with the memory card, an unnecessary operation does not occur. Also, unlike the method of identifying the presence or absence of a new function depending on the shape of the memory device, it becomes possible to use a memory card with a new function by a device that does not support the new function. It is advantageous.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a security-compatible memory card according to an embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a memory card that does not support security in an embodiment of the present invention.
FIG. 4 is a schematic diagram showing a configuration of a file system processing hierarchy of a flash memory according to an embodiment of the present invention.
FIG. 5 is a schematic diagram illustrating a format of a physical configuration of data in a flash memory according to an embodiment of the present invention.
FIG. 6 is a schematic diagram illustrating a configuration of a boot block of a flash memory.
FIG. 7 is a schematic diagram illustrating a configuration of boot and attribute information of a boot block of a flash memory.
FIG. 8 is a schematic diagram showing key relationships in content according to an embodiment of the present invention.
FIG. 9 is a block diagram for explaining encryption processing at the time of recording in one embodiment of the present invention.
FIG. 10 is a schematic diagram for illustrating authentication processing according to an embodiment of the present invention.
FIG. 11 is a schematic diagram for explaining encryption processing during recording according to an embodiment of the present invention;
FIG. 12 is a block diagram for explaining encryption processing during reproduction according to an embodiment of the present invention.
FIG. 13 is a schematic diagram for explaining encryption processing during reproduction according to an embodiment of the present invention;
FIG. 14 is a timing chart for explaining an interface between the recorder and the memory card according to the embodiment of the present invention.
FIG. 15 is a timing chart for explaining an interface between the recorder and the memory card in the embodiment of the invention.
FIG. 16 is a flowchart used for explaining the operation of the embodiment of the invention.
FIG. 17 is a flowchart for explaining an example in which the present invention is applied to a function other than a security function;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Recorder, 2 ... CPU, 3 ... Security block, 7 ... Audio encoder / decoder, 11 ... Memory interface, 40 ... Memory card corresponding to security, 40 '... Security non-compliant memory card, 43 ... S / P, P / S, IF block, 42 ... Flash memory, 52 ... Security block

Claims (7)

In either, removable memory device capable of recording or reproducing of the data processing apparatus having no data processing apparatus and encryption function having an encryption function,
Non-volatile memory;
A circuit having an encryption function;
Interface means arranged for data communication between the data processing device and the non-volatile memory,
In the storage area of the non-volatile memory, record identification information as to whether or not the encryption function is present in a predetermined storage area that is first read by the data processing device when used ,
When connected to a data processing device having an encryption function, after the identification information is read, an authentication operation is performed, and after the authentication is established, a write operation or a read operation to the nonvolatile memory is performed,
When connected to a data processing device that does not have an encryption function, after the identification information is read, a write operation or a read operation to the nonvolatile memory is performed without performing an authentication operation. Memory device.   2. The memory device according to claim 1, wherein the circuit having the encryption function is provided to protect a digital audio signal recorded in the nonvolatile memory.   2. The memory device according to claim 1, wherein a unique storage key is stored for each memory device used in the circuit having the encryption function.   2. The memory device according to claim 1, wherein the circuit having the encryption function includes a random number generation circuit.   2. The memory device according to claim 1, wherein the circuit having the encryption function includes a DES encryption circuit. In a data processing device that is detachable and uses a memory device including a nonvolatile memory as a recording medium,
A circuit having an encryption function;
An interface means for communicating with the memory device mounted in the mounting unit;
When a memory device is installed in the mounting unit, the memory device encryption is performed in the storage area of the non-volatile memory, regardless of whether the memory device has an encryption function or does not have an encryption function. First, a predetermined storage area in which identification information indicating whether or not to have a memory function is stored is read, and when the mounted memory device is used , the mounting unit is read according to the identification information in the predetermined storage area that is read first. Determine whether the memory device attached to the memory device has an encryption function;
When connected to a memory device having an encryption function, after the identification information is read out, an authentication operation is performed, and after the authentication is established, the circuit having the encryption function of the data processing device is used. A write operation or read operation to the non-volatile memory is performed,
A data processing device characterized in that, when connected to a memory device that does not have an encryption function, a notification that the memory device cannot be used is made . In a data processing method of writing or reading information to or from a memory device having a nonvolatile memory that is detachable from the data processing device by the data processing device,
When a memory device is mounted on the mounting portion of the data processing device, the memory device in the storage area of the non-volatile memory can be used regardless of whether the memory device has an encryption function or does not have an encryption function. First, a predetermined storage area in which identification information indicating whether or not the device has an encryption function is stored is read, and when using the attached memory device, the identification information in the predetermined storage area to be read first is used. Determining whether the memory device attached to the attachment unit has an encryption function;
If it is connected to a memory device having an encryption function, after the identification information is read, the authentication operation is performed by that you use the circuit after successful authentication with the encryption function of the data processing device, A write operation or a read operation to the nonvolatile memory is performed,
A data processing method characterized by notifying that a memory device cannot be used when connected to a memory device having no encryption function .

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