一、前言由于计算机技术的发展,使得比较复杂的加密和解密体制能够经济而且高速度地实现。同时随着分散数据处理、数据库以及利用通信卫星的数据通信的发展,需要保护与私人秘密有关的数据库、解决国际银行之间兑换结算系统(SWIFS)上的安全和验证问题。在这种背景下,以美国为中心,近几年来对密码的研究与开发取得了很大进展。1977年美国国家标准局制定了数据加密标准(DES)作为政府内部使用的数据处理用加密制度,并且建议民间也采用DES。现在,执行DES的硬件和软件正在商品化。同时Diffie和Hellman还提出了公开密钥加密体制。这种体制能够避免传统密码体制的密钥分发问题,又显示了数 First, the preface Due to the development of computer technology, making the more complex encryption and decryption system can be economical and high-speed implementation. At the same time, with the development of decentralized data processing, databases and the use of communication satellites for data communications, databases related to private secrets need to be protected to address security and verification issues in exchange-settlement systems (SWIFS) between international banks. In this context, the United States has made great strides in the research and development of cryptography in recent years. In 1977, the National Bureau of Standards of America set forth the Data Encryption Standard (DES) as an encryption system for data processing used by the government, and recommended private use of DES as well. Now, the hardware and software that implement DES is commercializing. At the same time Diffie and Hellman also proposed a public key cryptosystem. This system can avoid the traditional cryptosystem key distribution problem, but also shows the number