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。

-DES uses a 56-bit key and an additional 8-bit parity bit, resulting in the largest 64-bit packet size. This is an iterative block cipher, using the technology known as the Feistel, which will encrypt the text block half. The use of sub-key pair, half of which application circulatory function, and then the output with the other half to " exclusive or"　operator　followed by the exchange of the two and a half, this process will continue, but in the end a cycle of non-exchange. DES uses 16 cycles.