A novel e-mail protocol using three-party password-authenticated key exchange

With the rapid development of Internet, e-mail authentication becomes more and more important. However, many existing e-mail authentication protocols are not secure enough. In 2005, Sun et al. proposed two e-mail protocols and claimed that can provide perfect forward secrecy. In 2007,Raphael showed the weaknesses of the two e-mail protocols. The first protocol can't securely against unknown key-share attack and the second protocol can't provide the perfect forward secrecy. It was contradictory to Sun et al.'s claimed. Therefore in this paper, we propose a novel e-mail protocol using three party password-authenticated key exchange to conquer the weaknesses of Sun et al. 's protocols.