des加密算法的实现，DES算法为密码体制中的对称密码体制，又被成为美国数据加密标准，是1972年美国IBM公司研制的对称密码体制加密算法。其密钥长度为56位，明文按64位进行分组，将分组后的明文组和56位的密钥按位替代或交换的方法形成密文组的加密方法。DES加密算法特点：分组比较短、密钥太短、密码生命周期短、运算速度较慢。(The symmetric cryptosystem in the DES algorithm for the password system, has been became the data encryption standard, was developed by the United States in 1972 IBM symmetric cryptosystem encryption algorithm. Its key length is 56, expressly groups, according to a 64 - bit will clear after the grouping and 56 set of keys according to a replacement or exchange method to form cipher group encryption method)