基于加密与签名的电子邮件客户端实现

本文重点研究了如何实现互联网端到端的安全电子邮件系统。首先，实现了“数字信封”，通过结合 AES和RSA算法的特点，使用AES加密邮件内容，RSA加密 AES密钥，从而使邮件信息更加安全，并且解决对称算法密钥传递问题。其次，实现了“数据的完整性”，通过MD5算法的不可逆性，实现了“邮件指纹”，保证邮件数据的完整性。最后，实现了安全电子邮件系统，基于SMTP和POP3邮件协议，开发了邮件加解密传输系统。

Realization of E-mail Client Based on Signature and Authentication

This paper focuses on how to achieve the end-to-end secure e-mail system of the internet.First, we have achieved a “digital envelope”.By combining with the characteristics of the AES and RSA algorithm , e-mail message is encrypted by AES key which is encrypted by RSA, and becomes more secure.This way solves the symmetric algorithm key delivery.Second, we have achieved data integrity.By the irreversibility of the MD5 algorithm,“e-mail fingerprint” can ensure the integrity of the mes-sage data.Lastly, secure e-mail system is achieved.Basing on SMTP and POP3 mail protocol, we have developed the e-mail en-cryption and decryption transmission system .