AbstractWe introduce a new cryptographic primitive identity-based anonymous proxy signcryption which provides anonymity to the proxy sender while also providing a mechanism to the original sender to expose the identity of the proxy sender in case of misuse. We introduce a formal definition of an identity-based anonymous proxy signcryption (IBAPS) scheme and give a security model for it. We also construct an IBAPS scheme and prove its security under the discrete logarithm assumption and computational Diffie–Hellman assumption. Moreover, we do an efficiency comparison with the existing identity-based signcryption schemes and anonymous signcryption schemes and show that our scheme is much more efficient than those schemes, we also compare the efficiency of our scheme with the available proxy signcryption schemes and show that our scheme provides anonymity to the proxy sender at cost less than those of existing proxy signcryption schemes.
