| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a communication system wherein a key acquisition method is selected, in response to revocation processing attended with the invalidation of part of receivers, when conducting secure communication among streaming content distribution apparatus and a plurality of the receivers. <P>SOLUTION: The streaming content distribution apparatus 2600 includes a key management section 2601 for updating a session key (SEK), when there exists a receiver to be revoked and generating a SEK update message 2611 including information for receivers 2620 which is not revoked to acquire the updated SEK; and a content encryption section 2602 for using the updated SEK to encrypt contents, and each of the receivers 2620 includes: a KEK storage section 2621 for recording a plurality of key encryption key data (KEK); a SEK acquisition section 2622 using the SEK update message 2611 for acquiring the updated SEK; and a streaming contents decryption section 2623 for using the SEK to decrypt the encrypted contents 2612. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
