Identity based broadcast encryption based on one to many identity based proxy re-encryption

Broadcast encryption schemes enable senders to efficiently broadcast ciphertexts to a large set of receivers in a way that only non-revoked receivers can decrypt them. Identity based broadcast encryption schemes are public key broadcast encryption using identity as the public key. In this paper, we show a novel way to construct identity based broadcast encryption. We introduce a new concept: one to many identity based proxy re-encryption. And we show how to construct efficient identity based broadcast encryption based on this primitive. Our scheme can achieve constant size public keys and private keys and linear size ciphertext. But our scheme no longer needs explicitly describing receiver set while all the other schemes need. Thus our scheme is an efficient broadcast encryption scheme compared with other schemes.