Identity-Based Traitor Tracing with Short Private Key and Short Ciphertext

Identity-based traitor tracing (IBTT) scheme can be utilized to identify a private (decryption) key of any identity that is illegally used in an identity-based broadcast encryption scheme. In PKC'07, Abdalla et al. proposed the first IBTT construction with short private key. In CCS'08, Boneh and Naor proposed a publickey traitor tracing, which can be extended to IBTT with short ciphertext. With a further exploration, in this paper, we propose the first IBTT with short private key and short ciphertext. Private key and ciphertext are both order of O(l 1+l 2), where l 1 is the bit length of codeword of fingerprint codes and l 2 is the bit length of group element. To present our IBTT scheme, we introduce a new primitive called identity-based set encryption (IBSE), and then describe our IBTT scheme from IBSE and fingerprint codes based on the BonehNaor paradigm. Our IBSE scheme is provably secure in the random oracle model under the variant of qBDHE assumption. © 2012 Springer-Verlag.