Patent ID: 7961887
Filing Date: 2011-06-14
Classification: G06F,H04L

Abstract:
1. A content distribution system comprising: a content encryption unit configured to encrypt a content by using a plurality of different session keys s a session key encryption unit configured to encrypt each of the plurality of different session keys with a public key corresponding to a decryption key unique to each user system, to obtain a plurality of encrypted session keys; a header information generation unit configured to generate, for a group including a plurality of user identification information items for respectively identifying a plurality of user systems to which the plurality of different session keys are assigned, header information which allows decryption of each encrypted session key assigned to each user system by using the decryption key unique to each user system belonging to the group, the header information including (a) the encrypted session keys, and (b) a first vector (L a hardware transmitter to transmit the header information and at least one of the plurality of encrypted contents to the plurality of user systems.