des算法源码

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。-des algorithm source code for DES algorithm of the symmetric cryptosystem cryptosystem, was to become the United States Data Encryption Standard, is the United States in 1972 developed by IBM Corporation symmetric encryption algorithm cryptosystem. Its key length 56, 64 explicitly grouped according to specific sub-group and after the 56-bit key by an alternative method or exchange group formed ciphertext encryption methods. DES encryption algorithm characteristics: short packet, the key is too short, short life-cycle password, slower speed of operation.