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 since signed messages are not transmitted with these kinds of signatures. There are a few schemes for this notion: Singh and Verma’s scheme and Yoon et al.’s scheme. Unfortunately, Tian et al. by presenting two forgery attacks show that Singh and Verma’s scheme is not secure, and also Yoon et al.’s scheme does not support provable security. The contributions of this paper are twofold. First, we review Yoon et al.’s scheme 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 CDH assumption in the random oracle model. Furthermore, our scheme is more efficient than (as efficient as) previous identity-based proxy signatures.