明文按64位进行分组，密钥长64位，密钥事实上是56位参与DES运算（第8、16、24、32、40、48、56、64位是校验位， 使得每个密钥都有奇数个1）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。-The plaintext is grouped by 64 bits, the key is 64 bits long, and the key is actually 56 bits involved in the DES operation (bits 8, 16, 24, 32, 40, 48, 56, 64 are parity bits, The key has an odd number of 1) after the group of the plaintext group and the 56-bit key in place by bit or exchange method to form a ciphertext group encryption method.