A Novel ID-Based Verifiably Encrypted Signature without Random Oracle

The verifiably encrypted signature schemes proposed by Asokan solved the fairness problem in the fair exchange process. In the work, we propose an ID-based strong unforgeability verifiably encrypted signature scheme without random oracles, and show that the security of the scheme is based on the difficulty of solving the computational Diffie-Hellman problem. Our scheme is obtained from a modification of Waters¿ recently proposed signature schemes. This is the first time that an ID-based verifyably encrypted signature schemes is proved in the standard model.