DES 使用一个 56 位的密钥以及附加的 8 位奇偶校验位（每组的第8为作为奇偶校验位），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 轮循环，使用异或，置换，代换，移位操作四种基本运算。-DES uses a 56 bit key and an additional 8 bit parity bit (n = eighth as the parity bit), the largest 64 bit packet size. This is a block cipher an iterative, using a technology called Feistel, which will be encrypted text block into two halves. For one half of application of circular functions using the sub key, then the output of the "exclusive or" operation and the other half　then exchange the two halves, this process will continue, but at the end of a cycle does not exchange. DES uses 16 cycles, using XOR, replacement, replacement, shift operation of four basic operations.