An Improved ID-based Restrictive Partially Blind Signature Scheme

Recently, the first ID-based restrictive partially blind signature scheme from bilinear pairing is proposed by Chen et al., which extends the concept of blind signature and possesses the excellent features of partially blind signature, restrictive blind signature and ID-based cryptosystem simultaneously. However, its computational cost is rather high. In order to improve its efficiency, Hu et al. presented another efficient scheme which requires less computing cost. Unfortunately, we find that an adversary can change the predetermined common information, which may include the expiry date and the face value of the e-cash in electronic cash system, without being discovered by the signer. So Hu et al.psilas scheme has security flaw when it is used in electronic cash system. In this paper, we present an improved ID-based restrictive partially blind signature scheme from bilinear pairing which overcomes the security weakness of Hu et al.psilas scheme. We analyze the security of our scheme in the random oracle model and compared the efficiency of our scheme with previous schemes.