随着互联网的迅速发展,使得电子邮件成为人们进行信息交流的重要工具,但是,在电子邮件飞速发展的同时,安全问题也越来越严重。目前,电子邮件系统的发展面临着机密泄漏、信息欺骗、病毒侵扰、垃圾邮件等诸多安全问题的困扰,保护邮件安全最常用的方法就是加密。 With the rapid development of the Internet, e-mail has become an important tool for people to exchange information. However, with the rapid development of e-mail, security problems are getting worse. At present, the development of e-mail system is confronted with many security problems such as confidential leak, information deception, virus intrusion and junk mail. The most commonly used method to protect e-mail is encryption.