Provable Secure ID Based Designated Verifier Proxy Signature Scheme without Pairings

Abstract

Identity (ID) based cryptosystem simplifies the key management and revocation problem. Proxy signature is an active cryptographic research area. As a variant of proxy signature, researchers proposed many ID-based designated verifier proxy signature (IBDVPS) schemes from pairings. Now a days, pairing is regarded as one of the very expensive cryptographic operation since the cost of computing a single pairing operation is much higher than the scalar multiplication on elliptic curve group. On the other side, map-to-point hash function is also very expensive operation. To simplify the key management, to reduce the size of the signature and to save the time of running the cryptographic operations, we propose the first IBDVPS scheme based on elliptic curve discrete log problem (ECDLP). Our scheme is secure against adaptive chosen message and identity attacks. Due to the design of saving running time and reducing the signature size, our proposed scheme can be more applicable in the practical applications than the previously proposed schemes.