Abstract: Identity-based signcryption was a cryptography scheme with low computation cost and simple key management, which was suitable to guarantee the confidentiality and authentication of information. Zhang, et al proposed an efficient identity-based signcryption scheme, and provided security provement in the random oracle model. Through analysis, it was found out that Zhang’s signcryption scheme was imperfect. To avoid the defect, a new identity-based signcryption scheme was proposed, whose security was proved in the random orcale model. Both the theoretical analysis and the experimental results show that proposed scheme is efficient and suitable for practical application.

Key words: identity-based signcryption; provable security; bilinear pairing; random oracle model