Identity Based Proxy Signature from RSA without Pairings

Abstract

RSA is a key cryptography technique and provides various interfaces for the applied software in real-life scenarios. Although some good results were achieved in speeding up the computation of pairing function in re- cent years, the computation cost of the pairings is much higher than that of the exponentiation in a RSA group. So it is still interesting to design efficient cryptosystems based on RSA primitive. A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. Most identity based proxy signature schemes currently known employ bilinear pairings. In this paper, an identity based proxy ring signature (IBPS) scheme from RSA without pairings is constructed, and the security is proved under the random oracle model.