基于整数分解问题的新型代理签名方案

Proxy signature is a useful cryptographic primitive for delegating the signing powers and has been suggested for use in many real world applications. The existing proxy signature scheme from factorization assumption are either insecure or inefficient. In this paper, we propose a novel, efficient and provably secure proxy signature scheme from factorization. Our construction makes use a factorization based key-exposure free chameleon hash function in the delegation phase and the proxy signer needs only to find a collision to a chameleon hash value to generate a valid proxy signature. As a result, our scheme is highly efficient in terms of the computation of the proxy signer. We also provide a formal security proof by classifying the adversaries into three categories. Comparisons demonstrate that the new scheme outperforms the known ones in terms of security, computational efficiency and the length of the public key.