A short ID-based proxy signature scheme

The notion of identity-based proxy signature with message recovery feature has been proposed to shorten identity-based proxy signatures and improve their communication overhead because signed messages are not transmitted with these kinds of signatures. There are a few schemes for this notion: the schemes of Singh and Verma and Yoon et al. Unfortunately, Tian et al., by presenting two forgery attacks, show that Singh and Verma scheme is not secure, and also, the scheme of Yoon et al. does not support provable security. The contributions of this paper are twofold. First, we review the scheme by Yoon et al. and discuss why it does not have message recovery property, and consequently, it is not short. Second, we propose a short identity-based proxy signature scheme with the help of message recovery property and show that it is secure under computational Diffie-Hellman assumption in the random oracle model. Furthermore, our scheme is more efficient than (as efficient as) previous identity-based proxy signatures. Copyright (C) 2014 John Wiley & Sons, Ltd.