Design and analysis of Chameleon signature scheme with time limit

A new Chameleon signature scheme with time limit is proposed based on Chameleon signature. A good way is offered to solvethe problem of signature with an appointed recipient and time limit. Before the time limit expires, the signature is validated in the schemeonly by the appointed recipient. After the time limit passes, the signature is converted into a conventional digital signature and is publiclyvalidated. Furthermore, anyone can verify whether the signature is converted on time. This scheme is simply designed and easily im-plemented. And its signature efficiency and security are better than existing convertible Chameleon schemes'.