Information processing device, information processing method and program storage medium

• US 20030105956A1
• Filed: 10/10/2002
• Published: 06/05/2003
• Est. Priority Date: 11/09/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Asano, Tomoyuki, Ishiguro, Ryuji
• Granted Patent: US 7,224,804 B2
• Time in Patent Office: Days
• US Class Current: 713/158
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G06F 2221/2135 Metering
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00166 involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/00188 involving measures which result in a restriction to authorised devices recording or reproducing contents to/from a record carrier
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00253 wherein the key is stored on the record carrier
• CPC Class Codes: G11B 20/00536 wherein encrypted content data is subjected to a further, iterated encryption, e.g. interwoven encryption
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0836 using tree structure or hierarchical structure
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying

Abstract

In an information processing system and method which enables detection processing of a revoked entity using an enabling key block (EKB), a device or a service provider as a revoked entity is determined on the basis of the enabling key block (EKB) used for key distribution in a tree structure. ID which enables position identification in the hierarchical key distribution tree is stored in a public key certificate and tracing processing using a tag of the enabling key block (EKB) is executed on the basis of the ID acquired from the public key certificate, thus determining whether or not the ID is of a position where EKB processing (decryption) is possible and determining the presence/absence of revocation of an entity corresponding to the ID.

Claims

1. An information processing device, associated with respective leaves of a hierarchical tree structure in which unique keys are associated with nodes and leaves, having a key set stored therein, the key set consisting of leaf key corresponding to each leaf of the hierarchical tree structure and node keys on paths to upper layers,

wherein the information processing device comprising a constitution for executing verification processing as to whether an entity corresponding to a node or a leaf is a revocation entity, which is an entity to be revoked, by determining whether or not an enabling key block (EKB) including encrypted key data resulting from encryption of a renewal node key of the hierarchical tree structure by a subordinate node key or a leaf key can be decrypted by a stored key set for an entity to be verified, the determination as to whether decryption is possible or not being executed by trace processing of a key location identification tag in the enabling key block (EKB) based on an identifier of the entity to be verified.

2. The information processing device as claimed in claim 1, wherein the identifier of the entity to be verified includes position information of the corresponding node or leaf of the entity in the hierarchical tree structure, and

the key location identification tag in the enabling key block (EKB) is constituted as a tag for identifying the presence or absence of encrypted key data on a subordinate layer of each of the encrypted key data in the enabling key block (EKB),

the trace processing being executed as the processing for tracing the tag on the basis of the position information of the entity in the hierarchical tree structure, included in the identifier of the entity to be verified.

3. The information processing device as claimed in claim 1, wherein the identifier of the entity to be verified includes position information of the corresponding node or leaf of the entity in the hierarchical tree structure, and

the key location identification tag in the enabling key block (EKB) is constituted as a tag for identifying the presence or absence of encrypted key data on a subordinate layer of each of the encrypted key data in the enabling key block (EKB),

the information processing device having a constitution such that determination as to whether the node position or leaf position corresponding to the entity to be verified can be reached or not is executed by the trace processing of the tag based on the identifier of the entity to be verified, and in case the position cannot be reached, determination as to whether decryption is possible or not is executed by determining whether it belongs to a subordinate layer of a node key that is not renewed.

4. The information processing device as claimed in claim 1, wherein the identifier of the entity to be verified is an identifier stored in a public key certificate of the entity,

the information processing device having a constitution such that the identifier of the entity to be verified is acquired from the public key certificate of the entity.

5. The information processing device as claimed in claim 1, wherein in decrypting an encrypted content provided from an entity corresponding to a node or leaf constituting the hierarchical tree structure,

the identifier of the entity is acquired from a public key certificate of the entity and the trace processing of the tag of the enabling key block (EKB) based on the acquired identifier is executed, thus determining whether the entity is a revocation entity or not and executing decryption processing of the encrypted content based on a content encryption key Kcon acquired from the enabling key block (EKB).

6. An information processing method in an information processing device, associated with respective leaves of a hierarchical tree structure in which unique keys are associated with nodes and leaves, having a key set stored therein, the key set consisting of leaf key corresponding to each leaf of the hierarchical tree structure and node keys on paths to upper layers,

wherein the information processing method comprising a constitution for executing verification processing as to whether an entity corresponding to a node or a leaf is a revocation entity, which is an entity to be revoked, by determining whether or not an enabling key block (EKB) including encrypted key data resulting from encryption of a renewal node key of the hierarchical tree structure by a subordinate node key or a leaf key can be decrypted by a stored key set for an entity to be verified, the determination as to whether decryption is possible or not being executed by trace processing of a key location identification tag in the enabling key block (EKB) based on an identifier of the entity to be verified.

7. The information processing method as claimed in claim 6, wherein the identifier of the entity to be verified includes position information of the corresponding node or leaf of the entity in the hierarchical tree structure, and

the key location identification tag in the enabling key block (EKB) is constituted as a tag for identifying the presence or absence of encrypted key data on a subordinate layer of each of the encrypted key data in the enabling key block (EKB),

the trace processing being executed as the processing for tracing the tag on the basis of the position information of the entity in the hierarchical tree structure, included in the identifier of the entity to be verified.

8. The information processing method as claimed in claim 6, wherein the identifier of the entity to be verified includes position information of the corresponding node or leaf of the entity in the hierarchical tree structure, and

the key location identification tag in the enabling key block (EKB) is constituted as a tag for identifying the presence or absence of encrypted key data on a subordinate layer of each of the encrypted key data in the enabling key block (EKB),

the information processing method comprising executing determination as to whether the node position or leaf position corresponding to the entity to be verified can be reached or not by the trace processing of the tag based on the identifier of the entity to be verified, and in case the position cannot be reached, executing determination as to whether decryption is possible or not by determining whether it belongs to a subordinate layer of a node key that is not renewed.

9. The information processing method as claimed in claim 6, wherein the identifier of the entity to be verified is an identifier stored in a public key certificate of the entity,

the information processing method comprising acquiring the identifier of the entity to be verified from the public key certificate of the entity.

10. The information processing method as claimed in claim 6, wherein in decrypting an encrypted content provided from an entity corresponding to a node or leaf constituting the hierarchical tree structure,

the identifier of the entity is acquired from a public key certificate of the entity and the trace processing of the tag of the enabling key block (EKB) based on the acquired identifier is executed, thus determining whether the entity is a revocation entity or not and executing decryption processing of the encrypted content based on a content encryption key Kcon acquired from the enabling key block (EKB).

11. A program storage medium for providing a computer program which causes a computer system to execute information processing in an information processing device, associated with respective leaves of a hierarchical tree structure in which unique keys are associated with nodes and leaves, having a key set stored therein, the key set consisting of leaf key corresponding to each leaf of the hierarchical tree structure and node keys on paths to upper layers,

the computer program stored in the storage medium comprising a verification processing step as to whether an entity corresponding to a node or a leaf is a revocation entity as an entity to be revoked,

the verification processing step including a step of execution by determining whether of not an enabling key block (EKB) including encrypted key data resulting from encryption of a renewal node key of the hierarchical tree structure by a subordinate node key or a leaf key can be decrypted by a stored key set for an entity to be verified,

the step of determining whether decryption is possible or not including a step of execution by trace processing of a key location identification tag in the enabling key block (EKB) based on an identifier of the entity to be verified.