A highly efficient and identity-based proxy signature scheme without random oracle

Recently, Au et al. proposed a hierarchical identity-based signature scheme and Hu-Huang proposed a proxy key generation protocol. Based on the both schemes, we present a novel identity-based proxy signature scheme. The proposed scheme is provablly secure in the standard model and its security can be reduced to the hardness assumption of the g-strong Diffie-Hellman problem. Compared with all existing identity-based proxy signature schemes secure in the standard model, the proposed scheme has the following two advantages: shorter signature length and less computational cost. So, the proposed scheme is very suitable for application in some low resource situations.