Attribute-Based Server-Aided Verification Signature

Attribute based signature (ABS) is a novel cryptographic primitive, which enables a party to sign messages for any predicate satisfied by their attributes. However, heavy computational cost is required during the verification procedure in most existing ABS schemes, which may need many pairing operations. Pairings are costly operation when compared to exponentiation in the base group. As a result, this presents a greatly challenge for resource-limited users, such as smart cards and wireless sensor. In other words, verification can hardly be done in these devices if attribute based signature is employed. We solve this problem by proposing a new notion called Attribute-Based Server-Aided Verification Signature. It is similar to normal ABS scheme, but it further enables the verifier to verify the signature with the assistance of an external server. In this paper, we find that there is a fault in Wu et al.’s security model against collusion attack, and design a concrete server-aided verification protocol for Li et al.’s attribute based signature. We also prove that our protocol is secure with random oracles.