An Anonymous Proxy Signature Scheme without Random Oracles
The concept of proxy signature was introduced in 1996, up to now many proxy signature schemes have been proposed. In order to protect the proxy signer's privacy, the concept of anonymous proxy signature, which is also called proxy ring signature, was introduced in 2003. Some anonymous proxy signature schemes, which are provable secure in the random oracle model, have been proposed. However, provable security in the random oracle model is doubtful when the random oracles are instantiated with hash functions in their implementation. Hence, the authors propose the first secure anonymous proxy signature scheme without random oracles.