JP5005477B2 - Nonvolatile memory device - Google Patents

Description

  The present invention relates to a technique for writing protected data into a nonvolatile storage device.

  In recent years, a memory card equipped with a non-volatile memory has expanded its market as a storage medium for digital cameras and mobile phones. The nonvolatile memory used in the memory card can be obtained at a low cost by increasing its capacity as the semiconductor process is miniaturized and reducing the bit unit price. As another aspect, an environment has been established in which all the copyrighted works packaged in various forms such as CDs, tapes and books have been converted into electronic data. In response to such a background, a distribution form in which a copyrighted work is converted into electronic data, stored in a memory card, and sold in place of a CD, a tape, or a book is gradually spreading.

  However, unlike conventional packages, electronic data can easily be copied without deterioration, so it is necessary to protect the copyright on the memory card and various methods are proposed. Has been. An example is briefly described.

  FIG. 17 is a block diagram of a nonvolatile memory device which is a conventional memory card.

  Reference numeral 1701 denotes a memory card, which includes a controller 1702 and a nonvolatile memory 1703. A controller 1704 controls the entire controller 1702 inside the controller 1702. Write data from the outside of the memory card 1701 is written to the nonvolatile memory 1703 via the host I / F (interface) 1705, the buffer 1706, and the memory I / F 1707.

  A session encryption / decryption unit 1708 is provided to exchange encrypted data between the memory card 1701 and the outside. The session encryption / decryption unit 1708 is stored in the buffer 1706 using a media key 1709, a random number generated from the random number generation unit 1710, and a session key generated based on a random number from a host outside the memory card 1701. Decrypts the write data from the host. The decrypted data is stored in the nonvolatile memory 1703. Here, the media key 1709 takes a value unique to each memory card 1701, and there is no memory card 1701 having the same media key 1709 value.

  FIG. 18 is a diagram showing a conventional mechanism for writing protected content. The left side is processing performed on the host side, and the right side is processing performed on the memory card side.

  First, the host acquires a key table and a media ID from the system information of the memory card (1801). Then, a media key is obtained together with the device number on the host side (1802). If this calculation is performed correctly, the host can obtain a media key, which is confidential information that cannot be read from the memory card. Next, random number information is exchanged between the host and the memory card (1803). The host and the memory card both calculate a random number exchanged with the session key and obtain a session key (1804).

  The host encrypts the content to be protected with the content key determined by the host itself (1805). Then, the host transfers the content encrypted with the content key to the memory card (1806). In the memory card, the transferred data is written in the user area (1806). The data to be written in the user area is only encrypted with the content key determined by the host, but if the content data and the content key are the same, the same data can be transferred and written to any memory card.

  The host encrypts the content key with the media key (1807). Next, the content key encrypted with the media key is encrypted with the session key (1808). Then, the content key encrypted with the media key and the session key is transferred to the memory card (1809). This is a rule that always encrypts data with a session key when writing data to a memory card protector.

  In the memory card, the transferred data is decrypted with the session key (1810). The decrypted data is written in the protected area (1811). The decrypted data is a content key encrypted with a media key.

  FIG. 19 is a sequence diagram for explaining normal data writing from the host to the memory card. First, in step 1901, the host issues a normal write command to the memory card. In step 1902, the host transfers write data to the memory card. In processing 1903, the memory card writes the write data from the host into the nonvolatile memory inside the memory card. During the writing period, the memory card notifies the host that the writing is in progress by outputting a busy signal. Finally, in step 1904, when the memory card finishes outputting the busy to the host, the host recognizes the end of writing. In this normal writing, data exchanged between the host and the memory card is not encrypted at all.

  Next, FIG. 20 is a sequence diagram for explaining protection data writing from a conventional host to a memory card.

  Initially, the memory card is in a state where writing to the protected area cannot be performed.

  First, in step 2001, the host issues a system information acquisition command to the memory card. In step 2002, the memory card transmits card system information to the host. Next, in process 2003, the host calculates card system information and a device number in the host to calculate a media key.

  The host transfers the random number generated by the host in step 2004 to the memory card in order to generate a session key from the calculated media key. The memory card transfers the random number generated by the memory card in step 2005 to the host. In step 2006, the memory card transitions to a state where data can be written to the protected area.

  In step 2007, the host issues a write command to the protection area, and in step 2008, the host transfers the data encrypted with the session key to the memory card. In processing 2009, the memory card decrypts the write data from the host with the session key and writes it to the nonvolatile memory inside the memory card. During the writing period, the memory card notifies the host that the writing is in progress by outputting a busy signal. Then, the memory card returns to a state where writing to the protected area cannot be performed. This requires a session key generation procedure in steps 2004 and 2005 every time data is written to the protected area. That is, by changing the encryption key with a random number every time data is written to the protection area, the safety of data writing to the protection area is further enhanced.

  Finally, in step 2010, the memory card finishes outputting busy to the host, and the host recognizes the end of writing.

  The data exchanged between the host and the memory card in writing data to the protection area is encrypted with a different key for each write data.

  FIG. 21 is a sequence diagram when a write command to the protection area is issued from the host even though the memory card cannot write to the protection area.

  Even if the host issues a write command to the protected area in step 2101 while the memory card cannot write to the protected area, the memory card returns an illegal command to the host in step 2102 as a response. The host cannot write data to the protected area.

  FIG. 22 is a diagram showing a conventional mechanism for reading content from a protected area. The left side is processing performed on the host side, and the right side is processing performed on the memory card side.

  First, the host acquires a key table and a media ID from the system information of the memory card (2201). Then, a media key is obtained together with the device number on the host side (2202). If this calculation is performed correctly, the host can obtain a media key, which is secret information that cannot be read from the memory card. Next, random number information is exchanged between the host and the memory card (2203). The host and the memory card both calculate a random number exchanged with the session key to obtain a session key (2204).

  In response to a protected area read request from the host, the memory card reads the content key encrypted with the media key written in the protected area (2205) and encrypts it with the session key (2206). The data is read and transferred to the host (2207).

  The host first decrypts the data read from the memory card with the session key (2208), and then decrypts it with the media key (2209), thereby obtaining the content key from the memory card.

  The host further reads the content encrypted with the content key from the user area of the memory card (2210) and decrypts it with the content key (2211) to obtain content data.

As described above, the content key written in the protection area of the memory card 1701 is encrypted with the media key, which is confidential information unique to each memory card. Further, the exchange with the outside of the memory card 1701 is performed by generating a different key with a different random number for each writing of a media key that is secret information unique to each memory card and performing a random number calculation.
JP 2002-26898 A

  However, according to the above method, some troublesome procedures are required to write the content data to the memory card. One is that the media key unique to the memory card needs to be calculated from each memory card by calculation, and the other is that it is necessary to encrypt the media key every time it writes with a session key that calculates a random number. .

  That is, it is necessary to write data by encrypting with a different key for each memory card, and it is necessary to write data by encrypting with a different key for each writing even for one memory card.

  As a result, in the conventional non-volatile storage device data writing system, even when the same content data is written to a plurality of memory cards, the same data cannot be transferred to the memory card. When the same content such as movies, music videos, and music data needs to be written to a large number of memory cards, that is, a system for writing content data becomes complicated, and TAT decreases. Have the problem of doing.

  A non-volatile storage device according to the present invention is a non-volatile storage device that writes / reads data in accordance with an external access instruction, and stores a storage area for storing data in a non-volatile manner and write data from outside. A normal writing function for writing to an area; a media key unique to the nonvolatile storage device; an encrypted writing function for encrypting write data from the outside with the media key and writing as protected data to the storage area; and the storage area A session key generation function for generating a different session key for each data write / read, and a session encryption read function for reading the protected data written in the storage area with the session key and transferring the same to the outside It is characterized by having.

  The nonvolatile storage device further includes a decryption writing function for decrypting write data from the outside with the session key and writing it as protection data in the storage area.

  The nonvolatile storage device may further include a partial encryption writing function that encrypts a part of externally written data with the media key and writes the data as protection data in the storage area.

  The nonvolatile storage device further includes an encryption access determination unit that takes one of three states of “permitted”, “temporary permission”, and “prohibited”, and the state of the encrypted access determination unit is “prohibited” ", The encrypted write function is not allowed to function.

  In the nonvolatile memory device, the storage area stores encrypted access determination information that takes one of two states, “permitted” or “prohibited”, and the nonvolatile memory device is turned on. In response, the encrypted access determination information is read from the storage area, and the read information is reflected in the encrypted access determination unit.

  In the nonvolatile storage device, when the encrypted write function or the decrypted write function functions, the state of the encrypted access determination unit is set to “temporarily permitted”, and the state of the encrypted access determination information is set to It is characterized by “prohibited”.

  In the nonvolatile memory device, the encrypted access determination information is set to “permitted” in response to a format instruction from the outside.

  A data writing system to a nonvolatile storage device according to the present invention includes a nonvolatile storage device and a host device that writes data to the nonvolatile storage device, and the nonvolatile storage device stores data in a nonvolatile manner. A storage area for storing, a normal write function for writing write data from the host to the storage area, a media key unique to the non-volatile storage device, and encrypting the write data from the host with the media key And an encryption writing function for writing as protected data in the storage area, and the host device instructs the nonvolatile storage device to write so as to use the normal writing function, and the encryption Encrypted writing for instructing writing to the non-volatile storage device to use the encrypted writing function And a instruction function, characterized in that.

  Further, in the data writing system to the non-volatile storage device, the non-volatile storage device and the host device further generate a session key that is common to the non-volatile storage device and the host device and is different for each data write. A session key generation function is provided for each other.

  In the data writing system to the non-volatile storage device, the non-volatile storage device further encrypts a part of write data from the outside with the media key and writes the data as protection data in the storage area. And the host device further includes a partial encryption write instruction function that issues a write instruction to the nonvolatile storage device so as to use the partial encryption write function.

  According to the present invention, encryption with a media key unique to the nonvolatile storage device and encryption with a different session key for each writing are not required for writing the protected data. It is possible to easily write the content data. As a result, it is possible to simplify the system for writing content data in a factory that produces package media on which content has been written, and to improve TAT.

  A data writing system and a nonvolatile storage device according to the present invention will be described.

[1. System overview]
FIG. 1 is a schematic diagram showing a configuration example of a system for writing protection data to the nonvolatile storage device of the present invention.

  Reference numeral 101 denotes a PC (personal computer) that performs control for writing protection data. Reference numeral 102 denotes a parallel writing device for writing protection data to a plurality of memory cards under the control of the personal computer 101, and includes a plurality of mounting openings 103 for mounting a plurality of memory cards.

  FIG. 2 is a block diagram showing details of the system for writing data into the nonvolatile storage device and the nonvolatile storage device of the present invention. This system includes a host 201 and a memory card 202. The host 201 corresponds to the personal computer 101 and the parallel writing device 102 in FIG. The memory card 202 includes a controller 203 and a nonvolatile memory 204.

  The controller 205 controls the operation of the entire controller 203 inside the controller 203. Write data from the host 201 to the memory card 202 is written to the nonvolatile memory 204 via the host I / F 206, the buffer 207, and the memory I / F 208.

  A session encryption / decryption unit 209 is provided for exchanging encrypted data between the memory card 202 and the host 201. The session encryption / decryption unit 209 uses the session key generated based on the media key 210, the random number generated from the random number generation unit 211, and the random number from the host 201, to receive from the host 201 in the buffer 207. Decrypt write data. The decrypted data is stored in the nonvolatile memory 204.

  The controller 203 further includes an encryption access determination unit 212 that determines whether or not writing to a protected area that is not encrypted is permitted, and a media encryption unit 213 that encrypts data using a media key. The nonvolatile memory 204 has encryption determination information 214 inside. Here, the media key 210 takes a value unique to each memory card 202 as in the prior art, and there is no memory card 202 having the same media key 210 value.

  FIG. 3 is a table showing a configuration of information stored in the encrypted access determination unit 212 in the controller 203. The information stored in the encrypted access determination unit 212 includes the encrypted access determination information, the encryption procedure, and the session key. The encrypted access determination information can take three states: “permitted”, “temporary permitted”, and “prohibited”. Further, the encryption procedure takes two states, “executed” and “not implemented”. The session key stores a session key used when exchanging protected data between the host 201 and the memory card 202.

  FIG. 4 is a table showing a configuration of information stored in the encryption determination information 214 inside the nonvolatile memory 204. Possible values for the encryption determination information 214 are two states, “permitted” and “prohibited”.

  FIG. 5 shows an initialization sequence of the memory card 202.

  First, the host 201 applies a voltage to the memory card 202 mounted in step 501. In response to the voltage application, the memory card 202 initializes the memory card 202 in process 502. During the initialization, the memory card 202 reads the encryption determination information 214 from the nonvolatile memory 204 and stores it in the encryption access determination unit 212. Here, when the information recorded in the encryption determination information 214 is “permitted”, the memory card 202 stores data in the protected area without performing a procedure including session key generation that has been performed conventionally. Writable.

  In order to confirm whether or not the initialization inside the memory card 202 has been completed after applying a voltage to the memory card 202, the host 201 executes an initialization completion inquiry command a plurality of times until a response is returned in step 503. If the internal initialization process has been completed, the memory card 202 responds in step 504 that the initialization has been completed.

  Recognizing the end of initialization of the memory card 202, the host 201 issues a command for acquiring card information such as the ID, operating speed, operating voltage, and current of the memory card 202 in step 505. The memory card 202 receives the host 201 in step 506. Returns the information inquired from as a response.

  The host 201 that has obtained information on the memory card 202 issues a data read command to the memory card 202 in step 507. The memory card 202 returns the data to the host 201 in step 508.

[2. Write without using session key]
FIG. 6 shows a write sequence of protection data to the memory card 202. FIG. 5 shows a case where “permitted” (or “temporary permission”) is recorded in the encrypted access determination unit 212 in the process of FIG.

  First, in step 601, the host 201 issues a command for writing to the protected area. Conventionally, when a write command to the protected area is issued without generating a session key, the memory card 202 returns an illegal command response. However, in the memory card 202 of the present invention, the encrypted access determination unit 212 is returned. Since “permitted” (or “temporary permitted”) is recorded in the encrypted access determination information, an invalid response is not returned.

  Subsequently, the host 201 transfers the non-encrypted write data not encrypted with the session key to the memory card 202 in step 602. The memory card 202 originally writes data to the protected area of the non-volatile memory 204 after decryption with the session key in writing to the protected area, but writes data to the protected area without generating the session key. If so, data is written to the protected area of the non-volatile memory 204 in step 603 without decryption by the session key.

  Finally, in step 604, the memory card 202 finishes outputting the busy to the host 201, so that the host 201 recognizes the end of writing.

  The data exchanged between the host 201 and the memory card 202 in writing data to the protection area is not encrypted with the session key.

  FIG. 7 is a flowchart of the process of the control unit 205 in the write process 603 of FIG.

  First, in the state 701, the control unit 205 is in a command waiting state. Next, in determination 702, it is determined whether or not a write command to the protection area has been issued. If it is determined that a write command to the protection area has been issued, the process proceeds to determination 703. In determination 703, it is determined whether the encryption procedure of the encrypted access determination unit 212 is “performed”. This is a determination as to whether a conventional session key generation sequence is performed. If it is determined that it has already been performed, the process proceeds to determination 704. In determination 704, the state of the encrypted access determination information of the encrypted access determination unit 212 is determined. When the encrypted access determination information of the encrypted access determination unit 212 is “permitted”, the state transitions to the state 705, and when it is “prohibited” or “temporarily permitted”, the state transitions to the state 707.

  In the state 705, “prohibited” is written in the encryption determination information 214 of the nonvolatile memory 204. At this time, no change is made to the encrypted access determination unit 212. Subsequently, the state transits to state 706, and “prohibited” is recorded in the encrypted access determination information of the encrypted access determination unit 212.

  Thereafter, in state 707, after decrypting the session key for the write data from the host 201, the decrypted data is written to the protected area of the nonvolatile memory 204, and in state 708, the encrypted access determination unit 212 The encryption procedure is set to an “unimplemented” state, and the process returns to the state 701. The processing of 703 to 708 corresponds to the sequence after step 2007 in the conventional sequence diagram of FIG. However, the processing in the states 704 to 706 is processing newly added in the present invention.

  If it is determined in the determination 703 that the encryption procedure of the encrypted access determination unit 212 is “not implemented”, the process proceeds to the determination 709. In determination 709, the state of the encrypted access determination information of the encrypted access determination unit 212 is determined. When the encrypted access determination information of the encrypted access determination unit 212 is “prohibited”, the state transitions to the state 710 and a write error is notified to the host 201. The flow from 709 to 710 corresponds to the processing of the conventional sequence diagram of FIG.

  If the encrypted access determination information of the encrypted access determination unit 212 is “permitted” in the determination 709, the process proceeds to 711. In the state 711, “prohibited” is written in the encryption determination information 214 of the nonvolatile memory 204. Subsequently, the state transits to a state 712 and “temporary permission” is recorded in the encrypted access determination information of the encrypted access determination unit 212. In state 713, the write data transferred from the host 201 is written in the protected area of the nonvolatile memory 204 without decrypting the session key. The processing from the determination 709 to the states 711, 712, and 713 corresponds to the sequence diagram of FIG. This is processing for writing data from the host 201 to the memory card 202 without performing encryption / decryption of the session key.

  If it is determined in the determination 709 that the encrypted access determination information of the encrypted access determination unit 212 is “temporary permission”, this indicates that the processing of the state 712 has been performed once. Since the processes in steps 711 and 712 have already been executed and need not be performed again, the state transitions to the state 713.

  As described above, in the present invention, if the encrypted access determination information of the encrypted access determination unit 212 is in the “permitted” state, means for writing data from the host 201 to the memory card 202 without performing encryption / decryption of the session key Is provided. However, when the protection data is written in the protection area (process 708 or process 713), “prohibited” is always recorded in the encryption determination information 214 of the nonvolatile memory 204 (process 705 or process 711). Therefore, when the memory card 202 is initialized again, the encrypted access determination information of the encrypted access determination unit 212 is stored in the encryption determination information 214 of the nonvolatile memory 204 as described in the process 502 of FIG. Since the “prohibited” is reflected, the writing (state 713) in which the session key is not decrypted in FIG. 7 is not performed thereafter. Also, even if the host 201 accesses by executing the session key generation procedure as in the conventional case, the data encrypted by the session key can be decrypted and written to the memory card 202 as in the conventional case.

  FIG. 8 is a flowchart of session key generation. First, in the state 801, the control unit 205 is in a command waiting state. Next, in the determination 802, it is determined whether or not a session key generation procedure command has been issued. If it is determined that a session key generation procedure command has been issued, the process proceeds to the state 803. In state 803, a session key generation process is performed, and the state transitions to state 804. In the state 804, the encryption procedure of the encrypted access determination unit 212 is set to “performed”. In this state 804, when the encryption procedure of the encrypted access determination unit 212 is “performed”, it is determined that the encryption procedure is “performed” in the determination 703 of the flowchart of FIG. 7.

  FIG. 9 is a diagram showing a mechanism for writing protected data in the write sequence of FIG. The left side is processing performed on the host side, and the right side is processing performed on the memory card side. Unlike the conventional data writing in the protection area of FIG. 18, it can be seen that the protection data written in the protection area of the nonvolatile memory 204 is transferred between the host 201 and the memory card 202 without encryption. This is because it is not necessary to change the unique session key for the memory card 202 in writing data to the protected area, and the same data can be transferred to all the memory cards 202 and written to the protected area. Is shown.

  FIG. 10 is a flowchart for setting the encryption determination information 214 in the pre-shipment inspection in the manufacture of the memory card 202.

  In the state 1001, “permitted” is written in the encryption determination information 214 of the nonvolatile memory 204. By doing so, data can be written to the protected area in the memory card 202 without performing encryption / decryption of the session key.

  However, writing “permitted” in the encryption determination information 214 in this way is limited to a state in which the content to be protected at the time of shipment of the memory card 202 is not recorded at all in the protection area. This is because the concept of the present invention makes it possible to access the protected area with the same ease as normal access only when there is no data to be protected.

  As described above, in the data writing system and the nonvolatile storage device of the present invention, the state in which the data to be protected is not written in the protection area of the memory card 202, for example, the state immediately after the inspection of the memory card 202 The same write data can be transferred to any memory card 202 and written to the protected area without using a session key that is unique to the memory card 202 and given by a random number for each write data. .

[3. Encrypt write data with media key]
However, in the description so far, as shown in FIG. 9, the data to be written in the protection area is not encrypted with the media key that has been conventionally performed. A method for writing the data encrypted with the media key to the protected area of the memory card 202 while transferring the same data from the host 201 to any memory card 202 will be described below.

  FIG. 11 shows a sequence in which encryption is designated for the memory card 202 and data is written to the protected area. FIG. 5 shows a case where “permitted” (or “temporary permission”) is recorded in the encrypted access determination unit 212 in the process of FIG.

  First, in step 1101, the host 201 issues a write command to the protected area with encryption designation.

  Subsequently, in step 1102, the host 201 transfers unencrypted write data that is not encrypted by the session key or the media key to the memory card 202. Here, since the memory card 202 is writing to a protection area designated for encryption, when the write data from the host 201 is stored in the buffer 207, the media encryption unit 213 performs encryption with the media key 210. The encrypted data is written into the protected area of the nonvolatile memory 204 (1103).

  Finally, in step 1104, the memory card 202 finishes outputting the busy to the host 201, so that the host 201 recognizes the end of writing.

  The data exchanged between the host 201 and the memory card 202 in the data write to the protection area is not encrypted by the session key or the media key, but the data written in the nonvolatile memory 204 is converted to the data encrypted by the media key. Become.

  FIG. 12 is a flowchart of the process of the control unit 205 in the write process 603 of FIG.

  First, in the state 1201, the control unit 205 is in a command waiting state. Next, in determination 1202, it is determined whether a write command to the protection area has been issued. If it is determined that a write command to the protection area has been issued, the process proceeds to determination 1203. In determination 1203, it is determined whether the encryption procedure of the encrypted access determination unit 212 is “performed”. This is a determination as to whether a conventional session key generation sequence is performed. When it is determined that the processing has already been performed, the process proceeds to determination 1204. In determination 1204, the state of the encrypted access determination information of the encrypted access determination unit 212 is determined. When the encrypted access determination information of the encrypted access determination unit 212 is “permitted”, the state transitions to the state 1205, and when it is “prohibited” or “temporarily permitted”, the state transitions to the state 1207.

  In the state 1205, “prohibited” is written in the encryption determination information 214 of the nonvolatile memory 204. At this time, no change is made to the encrypted access determination unit 212. Subsequently, the state transits to the state 1206, and “prohibited” is recorded in the encrypted access determination information of the encrypted access determination unit 212.

  Thereafter, in state 1207, after decrypting the session key for the write data from the host 201, the decrypted data is written in the protected area of the nonvolatile memory 204, and in state 1208, the encrypted access determination unit 212 The encryption procedure is set to an “unimplemented” state, and the process returns to the state 1201. The processing from 1203 to 1208 corresponds to the sequence after step 2007 in the conventional sequence diagram of FIG. However, the processing in the states 1204 to 1206 is processing newly added in the present invention.

  If it is determined in the determination 1203 that the encryption procedure of the encrypted access determination unit 212 is “not implemented”, the process proceeds to the determination 1209. In determination 1209, the state of the encrypted access determination information of the encrypted access determination unit 212 is determined. When the encrypted access determination information of the encrypted access determination unit 212 is “prohibited”, the state transits to the state 1210 and a write error is notified to the host 201. The flow from 1209 to 1210 corresponds to the processing of the conventional sequence diagram of FIG.

  If the encrypted access determination information of the encrypted access determination unit 212 is “permitted” in the determination 1209, the process proceeds to 1211. In state 1211, “prohibited” is written in the encryption determination information 214 of the nonvolatile memory 204. Subsequently, the state transits to the state 1212, and “temporary permission” is recorded in the encrypted access determination information of the encrypted access determination unit 212. In the state 1213, the session key is not decrypted, the media key is encrypted, and the write data transferred from the host 201 is written in the protected area of the nonvolatile memory 204. The processing from the determination 1209 to the states 1211, 1212 and 1213 corresponds to the sequence diagram of FIG. This is processing for writing data from the host 201 to the memory card 202 without performing encryption / decryption of the session key.

  When it is determined in the determination 1209 that the encrypted access determination information of the encrypted access determination unit 212 is “temporary permission”, this indicates that the processing of the state 1212 has been performed once. Since the processes 1211 and 1212 have already been executed and need not be performed again, the state transitions to the state 1213.

  As described above, according to the present invention, if the encrypted access determination information of the encrypted access determination 212 is “permitted”, the media key is encrypted inside the memory card 202 and data is transferred from the host 201 to the memory card 202. Provides a means to write.

  FIG. 13 is a diagram showing a mechanism for writing data to the protection area in the write sequence of FIG. The left side is processing performed on the host side, and the right side is processing performed on the memory card side.

  Unlike the protection data writing in FIG. 9, the content key, which is the write data sent from the host 201 to the memory card 202 when writing to the protection area with encryption designation, is encrypted with either the session key or the media key. (1301). The memory card 202 encrypts the transmitted content key with a media key that is confidential information (1302). Thereafter, the encrypted data is written into the protected area of the nonvolatile memory 204.

  By doing so, the data written in the nonvolatile memory 204 can be in a state where the encryption unique to each memory card is performed.

  As described above, without performing encryption with the session key, the method of transferring data from the host 201 to the memory card 202 and writing it in the protected area of the memory card 202, and without performing encryption with the session key, A method has been described in which data is transferred from the host 201 to the memory card 202, and the data is encrypted with the media key of the memory card 202 and written to the protected area of the memory card 202.

  Here, a method of encrypting a part of data transferred to the memory card 202 with a media key by issuing a further developed command will be described.

  FIG. 14 shows a sequence in which an encrypted address is designated for the memory card 202 and data is written to the protected area. FIG. 5 shows a case where “permitted” (or “temporary permission”) is recorded in the encrypted access determination unit 212 in the process of FIG.

  First, in step 1401, the host 201 issues a write command to the protected area by specifying an encrypted address.

  Subsequently, in step 1402, the host 201 transfers unencrypted write data that is not encrypted by the session key or the media key to the memory card 202. Here, since the memory card 202 is writing to the protection area with the encryption address designation, the media encryption unit 213 uses the media key 210 when the write data from the host 201 is stored in the buffer 207, and the host Only the address portion specified in step 1401 from 201 is encrypted with the media key, and the encrypted data is written in the protected area of the nonvolatile memory 204.

  Finally, in step 1404, the memory card 202 finishes outputting the busy to the host 201, so that the host 201 recognizes the end of writing.

  The data exchanged between the host 201 and the memory card 202 in the data write to the protection area is not encrypted by the session key or the media key, but the data written to the nonvolatile memory 204 is only the address portion designated by the host 201. Becomes data encrypted with the media key.

[4. Determination of presence or absence of protected data]
Up to this point, “permitted” is written in the encryption determination information 214 of the nonvolatile memory 204 only at the time of shipping inspection of the memory card described with reference to FIG. This is because it is guaranteed that no content to be protected has been written yet when the memory card is shipped. Hereinafter, another case where “permitted” is written in the encryption determination information 214 of the nonvolatile memory 204 will be described.

  FIG. 15 is a flowchart of processing inside the memory card 202 when the host 201 issues a format command to the memory card 202.

  First, in the state 1501, the control unit 205 is in a command waiting state. Next, in a determination 1502, it is determined whether or not a format command has been issued. If it is determined that a format command has been issued, the flow goes to the state 1503. In the state 1503, the control unit 205 erases the data written in the nonvolatile memory 204 and then writes predetermined format data. By performing this processing, the content to be protected is erased and no longer exists in the protected area of the nonvolatile memory 204. Next, the state transits to the state 1504, and “permitted” is written in the encryption determination information 214. Finally, it returns to the state 1501. By this processing, the memory card 202 is in a state where there is no content to be protected and data can be written to the protected area without an encryption procedure.

  FIG. 16 is a flowchart of processing inside the memory card 202 when the host 201 issues an erase command to the protected area of the memory card 202.

  First, in state 1601, the control unit 205 is in a command waiting state. Next, in a determination 1602, it is determined whether or not a protection area erase command has been issued. If it is determined that a protection area deletion command has been issued, the process transits to a state 1603. In the state 1603, the control unit 205 erases the protection area of the nonvolatile memory 204, so that the protection area of the nonvolatile memory 204 is in a state where there is no content to be protected. Next, the state transits to the state 1604, and “permitted” is written in the encryption determination information 214. Finally, the process returns to the state 1601. By this processing, the memory card 202 is in a state where there is no content to be protected and data can be written to the protected area without an encryption procedure.

  If there is no data to be protected, there is no need for an encryption procedure for the protected area. Therefore, if it is possible to determine whether or not there is data to be protected, data writing to a protected area that does not require an encryption procedure is not limited to the above conditions.

[5. Summary]
As described above, when it is guaranteed that the content data to be protected has not been written in the memory card 202, for example, by writing “permitted” in the encryption determination information 214 at the time of shipping inspection or the like, it is still protected. During the period when the content to be written is not written, the same data can be transferred to the arbitrary memory card 202 and the protected data can be written in the protected area. Further, an arbitrary address portion of the protection data to be written can be encrypted and written with a media key unique to the memory card 202. After the protection data is written, the protection data can be read only by an encrypted interface that requires generation of a session key as in the prior art.

  In other words, a nonvolatile storage device capable of protecting data to the same extent as in the past and capable of writing the protected data by a much easier method than before when the data to be protected has not been written yet. A data writing system and a nonvolatile memory device are provided.

  The present invention can be applied to a technique for writing protected data to a nonvolatile storage device, and is particularly useful for shortening TAT and facilitating processing when writing data to be protected to a large number of nonvolatile storage devices.

Configuration example of system for writing protection data to nonvolatile storage device of the present invention The block diagram which showed the detail of the data writing system to the non-volatile storage device of this invention, and a non-volatile storage device Configuration table of information stored in the encrypted access determination unit Configuration table of information stored in encryption judgment information Memory card initialization sequence diagram Sequence diagram for writing data to the protected area Flow chart of data write processing to protected area Session key generation flowchart Diagram showing how data is written to the protected area Memory card inspection flowchart Sequence diagram for writing data to the protected area for encryption Flowchart of data write processing to protected area for encryption Diagram showing how data is written to the protected area where encryption is performed Sequence diagram for writing data to a protected area that is encrypted by addressing Format command flowchart Protected area deletion flowchart A block diagram of a conventional nonvolatile memory device The figure which shows the mechanism of data writing to the conventional protection area Conventional normal data writing sequence diagram Sequence diagram for writing data to a conventional protected area Sequence diagram of data write error to the conventional protection area The figure which shows the mechanism of data reading from the conventional protection area

Explanation of symbols

101 PC 102 Parallel writing device 201 Host 202 Memory card 203 Controller 204 Non-volatile memory 205 Control unit 206 Host I / F
207 Buffer 208 Memory I / F
209 Session encryption / decryption unit 210 Media key 211 Random number generation unit 212 Encryption access determination unit 213 Media encryption unit 214 Encryption determination information 1701 Memory card 1702 Controller 1703 Non-volatile memory 1704 Control unit 1705 Host I / F
1706 Buffer 1707 Memory I / F
1708 Session encryption / decryption unit 1709 Media key 1710 Random number generation unit

Claims (4)

A non-volatile storage device for writing / reading data according to an external access instruction,
A storage area for storing data in a nonvolatile manner;
A normal write function for writing external write data into the storage area;
A media key unique to the non-volatile storage device;
An encrypted writing function for encrypting external write data with the media key and writing it as protected data in the storage area;
A session key generation function for generating a different session key for each writing / reading of data to / from the storage area;
A session encryption read function that reads the protection data written in the storage area, encrypts it with the session key, and transfers it to the outside ;
A decryption writing function for decrypting externally written data with the session key and writing it as protected data in the storage area;
An encrypted access determination unit that takes one of three states: “permitted”, “temporary permitted”, or “prohibited”;
Have
When the state of the encrypted access determination unit is “prohibited”, the encrypted write function is not functioned.
A non-volatile memory device. In claim 1 ,
The storage area stores encrypted access determination information that takes one of two states, “permitted” or “prohibited”.
In response to power-on of the nonvolatile storage device, the encrypted access determination information is read from the storage area, and the read information is reflected in the encrypted access determination unit.
A non-volatile memory device. In claim 2 ,
When the encrypted writing function or the decryption writing function is functioned, the state of the encrypted access determination unit is “temporarily permitted”, and the state of the encrypted access determination information is “prohibited”.
A non-volatile memory device. In claim 3 ,
In response to a format instruction from the outside, the state of the encrypted access determination information is set to “permitted”.
A non-volatile memory device.

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