置换密码算法实现.置换密码算法的原理是不改变明文字符，而是按照某一规则重新排列消息中的比特或字符顺序，才而实现明文信息的加密。-Replacement password algorithm. Permutation cipher does not change the principle is expressly characters, but rearrange the message bits or characters in the order in which a rule, only to realize the encrypted plaintext information.