Secure Identity-Based Blind Signature Scheme for Online Transactions

Today, more and more business activities are done through online transactions. How to protect the personal privacy of customers in online transactions has become an urgent issue. Blind signature (BS) is suitable for online transactions because it can hide the specific content of the signed message. The security proofs of most BS schemes are given in the random oracle model (ROM). As we all know, the cryptographic scheme that is proven to be secure in ROM may be insecure in practical applications. In this paper, we fist study the security requirements for identity-based BS (IBBS) scheme, then design a concrete IBBS scheme and show the security proofs in the standard model. Finally, we compare the proposed scheme with the other two BS schemes. Requiring only three pairing operations, the proposed scheme is much efficient and is suitable for online transactions.