Distributed certified e-mail system for mobile users

We propose a new certified e-mail system which is based on the traditional cryptographic schemes and server-supported signature scheme for fairness and confidentiality of message. Since we intend to minimize the computational overhead of mobile device on public key algorithm, our proposed system becomes to be suitable for mail user who uses mobile devices such as cellular phone and PDA. Moreover, the proposed system is fault-tolerant, secure against mobile adversary and conspiracy attack, since it is based on threshold cryptography on server-side.