Memory device having secure non-volatile locking functionality

• US 7,962,713 B2
• Filed: 06/19/2003
• Issued: 06/14/2011
• Est. Priority Date: 06/25/2002
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Okaue, Takumi, Okubo, Hideaki, Tashiro, Jun, Nakanishi, Kenich
• Primary Examiner(s): Shah; Sanjiv
• Assistant Examiner(s): DILLON, SAMUEL A
• Application Number:
  US10/487,008
• Publication Number:
  US 20040243779A1
• Time in Patent Office: 2,917 Days
• Field of Search: 711145-164, 713189-194
• US Class Current: 711/163
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself

Abstract

A device and method is provided for maintaining, upon unlocking of a memory, the lock status of the memory prior to the memory being unlocked and recreating the lock status when power is turned on again. An information storage device, such as a memory card, performs unlocking of a memory in response to a command input from an information processing apparatus and stores lock status data prior to the memory being unlocked in a non-volatile memory (NVM). When the information storage device is turned off and then on, the information storage device recreates a lock status of the memory on the basis of the lock status data stored in the storage means and performs memory access control based on the recreated lock status.

Claims

1. An information storage device comprising:

a memory for storing data; and

a controller for performing access control on the memory,

wherein,

the controller is operatively configured to (1) establish, at both an initial physical placement of the information storage device in and subsequent interconnections with each of a plurality of information processing apparatus and without user intervention when so interconnected, an automatic authentication process performed between the information storage device and one of the plurality of information processing apparatus to unlock the memory in response to an automatic command input from the one of the plurality of information processing apparatus, (2) store lock status data corresponding to a unique identification for each of the plurality of information processing apparatus prior to the memory being unlocked in a storage unit, and (3) when the information storage device transitions from an off state to an on state, recreate a lock status of the memory on the basis of the lock status data stored in the storage unit and perform memory access control based on the recreated lock status,

one of a plurality of unique identifiers and one of a plurality of lock keys correspond to each of the plurality of information processing apparatus,

a key set comprises an identifier and a lock key,

the key set is utilized to lock and unlock the memory by communicating with the controller,

authentication that one of the plurality of information processing apparatus is authorized to access the memory of the information storage device is determined by the controller utilizing the key set,

the controller requires the key set utilized to lock the memory to unlock the memory,

the memory is locked according to three locking modes, the memory being locked in one of the three locking modes at a time, the three locking modes being standard locking, export locking and standard locking enabling group locking, in standard locking the key set being prevented from being output to another information processing apparatus for accessing the memory, and in export locking the key set being permitted to be output to another information processing apparatus for accessing the memory,

the key set includes at least one sub key set, the at least one sub key set including a sub identification and a sub lock key, the at least sub key set being permitted to be copied to each of the plurality of information processing apparatus during the export locking lock status, the sub key set being required to unlock the memory in response to the sub key set being utilized to lock the memory previously, and

the sub key set is imprinted to one of the plurality of information processing apparatus during the export locking or the standard locking enabling group locking.

2. The information storage device according to claim 1, wherein:

the information storage device is operatively configured to store lock status information serving as the lock status data of the information storage device in the storage unit, and

the controller is operatively configured to store the lock status information in a non-volatile memory (NVM) serving as first storage unit for maintaining information stored therein.

3. The information storage device according to claim 2, wherein the controller is operatively configured to copy and store the lock status information stored in the non-volatile memory (NVM) into a memory in the controller, the memory serving as second storage unit, after the information storage device is turned on again, and perform access control based on the copied and stored information.

4. The information storage device according to claim 1, wherein the controller performs processing in response to an unlock request from the information processing apparatus on the basis of the lock status recreated when the information storage device is turned on again, and the controller performs verification of a key set including the identifier (ID) and the lock key of the information processing apparatus having output the unlock request and, provided that the verification succeeds, performs unlocking based on the unlock request.

5. The information storage device according to claim 4, wherein the key set is a key set [ID, LK] consisting of the ID held by the information processing apparatus and the lock key (LK) associated with the ID, the information storage device has a lock master key (LMK) that is applicable to compute the lock key (LK), which is a hash value based on the relationship LK=H(LMK, ID), the hash value being computed for the ID by applying the lock master key (LMK), and the controller verifies the key set held by the information processing apparatus, the key set being input from the information processing apparatus, on the basis of the lock key (LK) obtained by computing the hash value by applying the lock master key (LMK).

6. The information storage device according to claim 5, wherein the controller generates a random number and receives, from the information processing apparatus, encrypted data [E(Lk, Rms)] generated by encrypting the random number (Rms) on the basis of the lock key (LK) held by the information processing apparatus, and the controller performs verification including checking of the received encrypted data against encrypted data [E(Lk, Rms)] computed on the basis of the lock key (LK) obtained by computing the hash value.

7. A memory access control method for an information storage device including a memory for storing data and a controller for performing access control on the memory, the method comprising:

an unlocking performing step of, at both an initial physical placement of the information storage device in and subsequent interconnections with an information processing apparatus and in response to an automatic command input from the information processing apparatus, establishing without user intervention an automatic authentication process performed between the information storage device and the information processing apparatus to unlock the memory, a key set comprising a unique identifier and a lock key corresponding to the information processing apparatus, wherein the authentication process verifies the key set was utilized to lock the memory before allowing access to the memory;

a lock-status-data storing step of storing lock status data corresponding to a unique identification of the information processing apparatus prior to the memory being unlocked in a storage unit, the memory is locked according to three locking modes, the memory being locked in one of the three locking modes at a time, the three locking modes being a standard locking, an export locking and a standard locking enabling group locking, in the standard locking the key set being prevented from being output to another information processing apparatus for accessing the memory, in the export locking the key set being permitted to be output to another information processing apparatus for accessing the memory; and

a memory access control step of recreating, when the information storage device transitions from an off state to an on state, a lock status of the memory on the basis of the lock status data stored in the storage unit and performing memory access control based on the recreated lock status.

8. The memory access control method according to claim 7, wherein the lock-status-data storing step includes a step of storing lock status information serving as the lock status data of the information storage device in a non-volatile memory (NVM) serving as first storage unit for maintaining information stored therein even after the information storage device transitions from an on state to an off state.

9. The memory access control method according to claim 8, further comprising a step of copying and storing the lock status information stored in the non-volatile memory (NVM) into a memory in the controller, the memory serving as second storage unit, after the information storage device is turned on again, wherein the memory access control step is a step of performing access control based on the copied and stored information.

10. The memory access control method according to claim 7, further comprising:

an imprinting step of imprinting a selection of a plurality of information processing apparatus including the information processing apparatus with at least one sub key set included within the key set for accessing the memory, the at least one sub key set including a sub identification and a sub lock key, the sub key set being required to unlock the memory in response to the sub key set being utilized to lock the memory previously, the lock status information includes the standard locking, the export locking and a group locking.

11. The memory access control method according to claim 7, further comprising an unlock-request-associated processing step of performing processing in response to an unlock request from the information processing apparatus on the basis of the lock status recreated when the information storage device is turned on again, wherein the unlock-request-associated processing step includes:

a verification step of performing verification of a key set including an identifier (ID) of the information processing apparatus having output the unlock request; and

an unlocking step of performing unlocking based on the unlock request provided that the verification succeeds.

12. The memory access control method according to claim 11, wherein the key set is a key set [ID, LK] consisting of the ID held by the information processing apparatus and the lock key (LK) associated with the ID, the information storage device has a lock master key (LMK) that is applicable to compute the lock key (LK), which is a hash value based on the relationship LK=H(LMK, ID), the hash value being computed for the ID by applying the lock master key (LMK), and the verification step includes a step of verifying the key set held by the information processing apparatus, the key set being input from the information processing apparatus, on the basis of the lock key (LK) obtained by computing the hash value by applying the lock master key (LMK).

13. The memory access control method according to claim 12, further comprising a step of generating a random number and receiving, from the information processing apparatus, encrypted data [E(Lk, Rms)] generated by encrypting the random number (Rms) on the basis of the lock key (LK) held by the information processing apparatus, wherein the verification step includes a step of performing verification including checking of the received encrypted data against encrypted data [E(Lk, Rms)] computed on the basis of the lock key (LK) obtained by computing the hash value.

14. A computer readable recording medium comprising instructions which when executed by a computer system causes the computer to implement a programmed method for performing memory access control on an information storage device including a memory for storing data and a controller for performing access control on the memory, the programmed method comprising:

an unlocking performing step of, at both an initial physical placement of the information storage device in and subsequent interconnections with an information processing apparatus and in response to an automatic command input from the information processing apparatus, establishing without user intervention an automatic authentication process performed between the information storage device and the information processing apparatus to unlock the memory, a key set comprising a unique identifier and a lock key corresponding to the information processing apparatus, wherein the authentication process verifies the key set was utilized to lock the memory before allowing access to the memory;

a lock-status-data storing step of storing lock status data corresponding to a unique identification of the information processing apparatus prior to the memory being unlocked in a storage unit;

a memory access control step of recreating, when the information storage device is turned off and then on, a lock status of the memory on the basis of the lock status data stored in the storage unit and performing memory access control based on the recreated lock status, the memory is locked according to three locking modes, the memory being locked in one of the three locking modes at a time, the three locking modes being standard locking, export locking and standard locking enabling rou locking, in standard locking the key set being prevented from being output to another information processing apparatus for accessing the memory, in export locking the key set being permitted to be output to another information processing apparatus for accessing the memory;

an imprinting step of imprinting a selection of a plurality of information processing apparatuses including the information processing apparatus with at least one sub key set included within the key set for accessing the memory, the at least one sub key set including a sub identification and a sub lock key, the sub key set may be copied to each of the plurality of information processing apparatus during the export locking, the sub key set being required to unlock the memory in response to the sub key set being utilized to lock the memory previously and the lock status being set to the export locking or group locking, the sub key set is imprinted to one of the plurality of information processing apparatus during export locking or group locking.