Secure Hash Algorithm(安全哈希算法)进行了简要描述,并对SHA-1算法的原理进行了深入分析。同时采用目前流行的C#语言对SHA-1算法进行了具体研究,设计了SHA-1加密系统。测试结果表明:加密系统可以准确实现中文信息和其他信息的SHA-1加密。-Secure Hash Algorithm (Secure Hash Algorithm), a brief descr iption of the SHA-1 algorithm and the principle of in-depth analysis. While using the popular C# language on the SHA-1 algorithms for specific studies, designed SHA-1 encryption system. Test results show that: encryption system can accurately achieve the Chinese and other information of SHA-1 encryption.