Proxy Broadcasting Signcryption Scheme

The concept of proxy signature introduced by Mambo, Usuda, and Okamoto in 1996 allows a designated person, called a proxy signer, to sign on behalf of an original signer. Sun proposed a time-stamped proxy signature scheme with traceable receivers which can ascertain whether a proxy signature is created time and trace the receivers who receive the proxy signature from the proxy signer.The proxy signature plays an important role in many applications and has received great attention since it was proposed. Encryption and signature schemes are fundamental cryptographic tools for providing privacy and authenticity respectively, respectively, in the public-key setting. Traditionally, these two important building-blocks of public-key cryptography have been considered as distinct entities that may be compose in various ways to ensure simultaneous message privacy and authentication. However, in the last years a new, separate primitive—called signcryption—has emerged to model a process simultaneously achieving privacy and authenticity. Signcryption is a new cryptographic technology, which simultaneously fulfills both the function of digital signature and public key encryption in a logically single step, and more efficient than the traditional"signature followed by encryption"approach. In this paper, the proxy broadcasting signcryption scheme with proxy signature, key agreement protocol and signcryption scheme has perfect forward secrecy, at the same time it can low the cost.