Identity-based signatures in standard model

Tight security proofs allow for shorter security parameters and better efficiency. In this paper, we firstly present a new signature scheme, SSSTR, which is strongly existentially unforgeable under adaptively chosen message attacks and whose security is tightly related to Strong Diffie–Hellman assumption in the standard model, and then give two identity-based signatures which are existentially unforgeable under adaptively chosen message and identity attacks and whose security is also tightly related to Strong Diffie–Hellman assumption in the standard model.