Provably secure proxy-protected signature schemes based on factoring

Proxy signature is an active cryptographic research topic, and a wide range of literature can be found nowadays, which suggest improvement and generalization of existing protocols in various direction. However, most of previously proposed schemes in these literature are based on discrete logarithm problem. To our best knowledge, there still does not exist an indeed proxy signature scheme based on integer factorization problem. In this paper, we propose two efficient provably secure proxy-protected signature scheme in Random Oracle Model. The first scheme is based on RSA problem and the second one is based on integer factorization problem. Compared to early proxy signature schemes, our schemes are more efficient and easy to implement. We believe they are particularly suitable for low-computation devices, such as smart cards, cell phones, pages etc.