DES算法的实现与改进，DES 使用一个 56 位的密钥以及附加的 8 位奇偶校验位，产生最大 64 位的分组大小。这是一个迭代的分组密码，使用称为 Feistel 的技术，其中将加密的文本块分成两半。使用子密钥对其中一半应用循环功能，然后将输出与另一半进行“异或”运算；接着交换这两半，这一过程会继续下去，但最后一个循环不交换。DES 使用 16 个循环，使用异或，置换，代换，移位操作四种基本运算。 数据加密算法

-DES algorithm implementation and improvement, DES uses a 56 bit key and an additional 8-bit parity, the greatest 64-bit block size. This is an iterative block cipher, using the technology known as Feistel, which will encrypt the text block into two halves. Half of them using the application of the key sub-circulatory function, and then the other half of the output with a " XOR"　operation　then swap the two and a half, this process will continue, but no exchange of the last cycle. DES uses 16 cycles, using XOR, replacement, substitution, shift operations are four basic operations. Data Encryption Algorithm