Secure Delegation of Signing Power from Factorization

Delegation of signing is a working way common in oce automation work, and is also an important approach to establish trust. Proxy signature is an important cryptographic primitive for delegating the signing powers and it has found many real world applications. The existing proxy signature schemes from factorization assumption are either insecure or inecient. In this paper, we propose a novel, ecient and provably secure proxy signature scheme from factorization. Our construction makes use of a factorization based key-exposure free chameleon hash function in the delegation phase and the proxy signer needs only to nd a collision to a chameleon hash value to generate a valid proxy signature. As a result, our scheme is highly ecient in terms of the computation of a proxy signature. 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 eciency and the length of the public key. Disciplines Engineering | Science and Technology Studies Publication Details Yu, Y., Au, M. Ho., Mu, Y., Susilo, W. & Wu, H. (2015). Secure delegation of signing power from factorization. The Computer Journal, 58 (4), 867-877. This journal article is available at Research Online: http://ro.uow.edu.au/eispapers/5030 Secure Delegation of Signing Power from Factorization Yong Yu, Man Ho Au2,∗, Yi Mu, Willy Susilo, Huai Wu 1. School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054, PR China 2. Centre for Information and Computer Security Research, School of Computer Science and Software Engineering, University of Wollongong, Wollongong, NSW 2522, Australia Email: [email protected] Delegation of signing is a working way common in office automation work, and is also an important approach to establish trust. Proxy signature is an important cryptographic primitive for delegating the signing powers and it has found many real world applications. The existing proxy signature schemes 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 of 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 a proxy signature. 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.