DES( Data Encryption Standard)算法，于1977年得到美国政府的正式许可，是一种用56位密钥来加密64位数据的方法。虽然56位密钥的DES算法已经风光不在,而且常有用Des加密的明文被破译的报道,但是了解一下昔日美国的标准加密算法总是有益的,而且目前DES算法得到了广泛的应用,在某些场合,她仍然发挥着余热.（如：UNIX的密码算法就是以DES算法为基础的）。将其修改为三重DES也能抵抗破解。下面是关于如何实现DES算法的语言性描述：-DES ( Data Encryption Standard ) algorithm, in 1977 the U.S. government　s official permission , is a 56 -bit key to encrypt 64 data . 56 keys of the DES algorithm scenery is not , and often with Des encryption expressly decipher reported , but look at the old standard encryption algorithm is always useful , but the DES algorithm has been widely used in a some occasions , she still plays a waste heat . (such as : UNIX password algorithm is DES algorithm -based ) . To modify the Triple DES is also resistant to cracking . The following is a descr iption language on how to achieve the DES algorithm :