Efficient Traceable Attribute-Based Signature

In an Attribute-Based Signature (ABS) scheme, only users whose attributes satisfy the signing predicate can create valid signatures. Typically, ABS schemes require two properties: unforgeability and privacy. In this paper, we propose a new structure and syntax for Traceable Attribute-Based Signature (TABS), which has a good balance between privacy and traceability. In a TABS scheme, the privacy of signers is also protected, each single user cannot link a signature to the identity (the set of attributes) of the signer. Meanwhile, given a malicious signature, the two trusted parties in our system can work together to trace the identity of the signer. Besides, we give a construction of a TABS scheme, and prove its existential unforgeability in the selective predicate security model under the q-Augmented Diffie-Hellman Exponent assumption. Compared to other ABS schemes, our scheme generates shorter signatures and is much more efficient.