ID-based proxy re-signature without pairing

Abstract

Proxy re-signature is a powerful cryptographic primitive, in which a proxy acts as a translator converts Alice’s signature into Bob’s signature by using the re-signature key. Proxy re-signature is a very useful tool for the interoperable DRM architecture and the passed path proof in cloud computing. However, the number of cloud users is very huge, so it is unsuitable to construct PKI in cloud computing. Moreover, the cloud users are usually mobile devices, which are constrained with processing and power limitations, and pairing is a very costly operation to them. Thus, ID-based proxy re-signature without pairing is an attractive issue for the applications in cloud computing. In this paper, based on Chai et al’s ID-based signature from quadratic residues, we propose the first unidirectional and single-use ID-based proxy re-signature, which is existential unforgeable in the random oracle model based on the factoring assumption.