实现对单文件的DES加密解密，不限制大小，DES加密部分自写，非调用，用于学习DES原理。-The realization of the single document DES encryption and decryption, no limit to the size, DES encryption part self written, non call, for learning DES principle.

DEs加密算法,用于对文件进行加密,并且速度较快,但是已破解,(DEs encryption algorithm, used for file encryption, and faster, but has been cracked,)