As the number of users has been explosively increased, e-mail has become one of the widely used applications on internet. However, an intrusion on the privacy of a user can happen by eavesdropping the communication channel between a sender and a recip...
As the number of users has been explosively increased, e-mail has become one of the widely used applications on internet. However, an intrusion on the privacy of a user can happen by eavesdropping the communication channel between a sender and a recipient or hacking the e-mail account of a user. PGP is a good solution to guard the user's privacy. It conceals the communicated messages (i.e., e-mail contents) and provides authentication of an origin. However, unfortunately, PGP can not guarantee user's privacy if the private key related with the recipient's public key is exposed by hacking or system failure. Therefore, we should consider the security of the users' private keys. In this paper, we introduce new e-mail protocols which keeps the user's privacy even though his/her private key is revealed.