动态密钥 把动态密匙保存在密文里，同样的明文，生产不同密文后能解密。加密后的密文可能是一些特殊字符，复制过程可能会丢失，所以用base64编码-Dynamic Key The dynamic key is stored in the ciphertext, the same plaintext, after the production of different ciphertext can be decrypted. Encrypted ciphertext may be some s