PHP mcrypt 相同的尾随字符

Question

运行时：

var_dump(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, '12345', '1abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz', MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND))));
var_dump(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, '12345', '2abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz', MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND))));
var_dump(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, '12345', '3abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz', MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND))));
var_dump(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, '12345', '4abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz', MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND))));
var_dump(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, '12345', '5abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz', MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND))));

它的结果是：

string 'X9VFmBzVWwUSoKPtE0VoEYxGkAPwVkUDQfQwF0wPDAVxedrGWE4oMCPBAF7FRBMoQsSUFwHhpknj/fHQqgQVPw==' (length=88)
string 'T/yn6lkyB73cEs57K2pUVNhFk2tDX02CbnBIU2c2I2VxedrGWE4oMCPBAF7FRBMoQsSUFwHhpknj/fHQqgQVPw==' (length=88)
string 'WysJWSV2k5gyYoQ4+hF0Uh2JqMJ6pTC8lcrgs1jmSklxedrGWE4oMCPBAF7FRBMoQsSUFwHhpknj/fHQqgQVPw==' (length=88)
string 'fMsJByfrZBYoQIgL/g+3i6jOPiaHh2Jf0vV59g1w1ZVxedrGWE4oMCPBAF7FRBMoQsSUFwHhpknj/fHQqgQVPw==' (length=88)
string 'Mw0AlrcC5v3v6swEg+wT+uTHf8MNrxdprD9GCpOe/45xedrGWE4oMCPBAF7FRBMoQsSUFwHhpknj/fHQqgQVPw==' (length=88)

注意字符串是如何以相同的字符集结尾的？

这应该发生吗？

我会认为因为数据不同，我每次都创建一个新的初始化向量会导致完全不同的输出。

是否存在另一种好的算法，可以在数据发生微小变化的情况下产生完全不同的输出？

http://codepad.viper-7.com/jVqpUU

Answer 1

类似的结果是由于ECB cipher block mode 每个块都单独加密。改用 CBC 等不同的模式，之前块的结果也会影响以后的块加密。