Improved identity based multi-receiver anonymous signcryption scheme

Abstract

Recently,Pang,et al proposed a novel identity based multi-receiver anonymous signcryption scheme (IBMRASC),which put into consideration both the sender's anonymity and the receiver's anonymity simultaneously.However,the analysis with respect to this scheme indicated that,under existing security models the adversary can distin-guish the ciphertexts associated with different plaintexts.Therefore,Pang's approach did not satisfy the requirement of indistinguishability against chosen ciphertext attacks (CCA).An improved scheme which is selective identity secure in the random oracle model was proposed.Under the CDH and Gap-BDH hard problem assumption,the improved scheme is both existentially unforgetable against chosen message attack and indistinguishable against adaptive CCA.

Keywords

• anonymity
• multi-receivers signcryption
• identity based signcryption
• random oracle