DES算法把64位的明文输入块变为64位的密文输出块，它所使用的密钥也是64位,其功能是把输入的64位数据块按位重新组合，并把输出分为L0 、R0两个部分，每部分各长32位.-The DES algorithm 64-bit input block of plaintext into a 64-bit output ciphertext block, it uses the key is 64, the function of which is 64-bit block of input data bits according to recombine, and the output is divided into L0 , R0 two sections, each 32 bits long each.