A revocable ID-based signcryption scheme

Signcryption scheme can efficiently perform encryption and signing procedures in a single step to obtain message confidentiality and non-reputation properties. As compared to the traditional public key system, identity (ID)-based public key system (IDPKS) can simplify the management of required certificates. However, how to revoke these compromised or misbehaving identities in the IDPKS becomes a critical problem. Recently, Tseng and Tsai proposed a novel construction in the IDPKS with revocation mechanism called revocable ID-based public key system (R-IDPKS). In this paper, we follow their R-IDPKS to propose an important cryptographic primitive "signcryption". Security analysis is made to demonstrate that the proposed scheme is provably secure and provides confidentiality and unforgeability.