Fully Collusion Resistant Black Box Traitor Revocable Broadcast Encryption with Short Private Keys
Broadcast encryption schemes enable senders to efficiently broadcast ciphertexts to a large set of receivers in a way that only nonrevoked receivers can decrypt them. Black box traitor revocable broadcast encryption schemes are broadcast encryption schemes that enable a tracer, who is given a pirate decoder, to identify traitors by black box accessing the given pirated decoder and to revoke traitors so identified. In this paper, we propose a fully collusion resistant black box traitor revocable broadcast encryption scheme in which the size of each private key is constant, the size of the public key is proportional to the number of receivers, and the sizes of ciphertexts are sub linear with respect to the number of receivers. The encryption procedure in our scheme requires only a public key. The tracing procedure in it requires only a public key and black box access to a resettable pirate decoder. The security of our scheme is proved in the generic bilinear group model if the subgroup decision assumption holds.
ICALP