Abstract: Chain encryption technology is a kind of email encryption technology, combining symmetric key algorithm and asymmetric key algorithm. Identitybased encryption is an encryption technique that uses users identity as public key. In order to achieve the secure transmission of emails in the network, a new email encryption system NMES based on national commercial cryptograph algorithm is designed, which combines the SM4 grouping algorithm of national commercial cryptograph algorithm with SM3 hash algorithm of national commercial cryptograph algorithm.It is designed on the basis of the identitybased signcryption technology and the chain encryption technology. The system achieves the absolute security of onetime pad (OTP), improves security and communication efficiency, and effectively solves the problem of certificate management and revocation, which has a wide range of application prospects.

Key words: national commercial cryptograph algorithm, signcryption algorithm, email, data encryption, network communication

摘要： 链式加密技术是一种重要的邮件加密技术，结合了对称密钥算法与非对称密钥算法的优点.基于身份的密码系统是使用用户标识作为公钥的非对称公钥密码体系.为了电子邮件在网络中的安全传输，结合国密SM4分组算法、国密SM3杂凑算法、基于身份的签密技术以及链式加密技术，设计了一种基于国密算法的新型电子邮件加密系统NMES.系统实现了一次一密绝对安全，提高了安全性和通信效率，有效地解决了证书管理、撤销困难的问题，具有广泛的应用前景.

关键词: 国密算法, 签密算法, 电子邮件, 数据加密, 网络通信