:ＤＥＳ体制是ＩＳＯ颁布的数据加密标准,通过对ＤＥＳ算法的分析,提出了用Ｃ语言实现数据加密标准ＤＥＳ算法,通过循环或迭代,将简单的基本运算(例如左移、右移、模2加法等)和变换(选择函数、置换函数)构造成数据流的非线性变换(加密变换或解密变换),从而实现对计算机数据进行密码保护。着重介绍了用Ｃ语言实现其加密的主要过程。关键词:数据加密 ＤＥＳ Ｃ语言-: DES system is ISO issued by the Data Encryption Standard, DES algorithm on the analysis of the C language standard DES data encryption algorithm, or through iterative cycle of simple basic operations (such as bits, death, die two Adder, etc.) and transform (choice function, function replacement) structural data streams into the nonlinear transformation (encryption or decryption transform Transform), thereby achieving data on the computer password protection. Highlights of the C language to achieve its key encryption process. Keywords : DES data encryption C language