A secure e-mail protocol using ID-based FNS multicast mechanism

Electronic mail (e-mail) has been used to transfer various types of electronic data in Internet. Usually, a user has to send an e-mail to a specific group of users with a secure delivery mechanism. In this paper, a novel and feasible e-mail delivery mechanism using the secure multicast protocol with an ID-based factorial number structure (FNS) is proposed in the multicast system. In the proposed e-mail delivery mechanism, the e-mail is required to be encrypted before sending out in order to safeguard the message via a public channel, such as wire public switching communication links and wireless communication systems. Without loss generality, the public-key system is adopted in the proposed secure multicast system for a convenient and easy key management. The proposed scheme outperforms the existing methods for more easily to construct secure e-mail system. Furthermore, the security of the proposed scheme is analyzed, including replay attack, sender impersonation attack, unknown key-share attack, forgery attack and insider attack. Finally, the computation complexities of the proposed mechanism are discussed. The result shows that the proposed scheme outperforms the CRT-based secure e-mail scheme.