SM4_DECRYPT

Description

Syntax

VARCHAR SM4_DECRYPT(VARCHAR str, VARCHAR key_str[, VARCHAR init_vector][, VARCHAR encryption_mode])

Returns the decrypted result, where:

• str is the text to be decrypted;
• key_str is the key. Note that this key is not a hexadecimal encoding, but a string representation of the encoded key. For example, for 128-bit key encryption, key_str should be 16-length. If the key is not long enough, use zero padding to make it up. If it is longer than that, the final key is found using a cyclic xor method. For example, if the 128-bit key used by the algorithm finally is key, then key[i] = key_str[i] ^ key_str[i+128] ^ key_str[i+256] ^ ...
• init_vector is the initial vector to be used in the algorithm, this is only valid for some algorithms, if not specified then Doris will use the built-in value;
• encryption_mode is the encryption algorithm, optionally available in variables.

danger

Until 2.1.6, function with two arguments will ignore session variable block_encryption_mode and always use SM4_128_ECB to do decryption.

Since 2.1.7, it works as expected.

Example

mysql> set block_encryption_mode='';
Query OK, 0 rows affected (0.11 sec)

mysql> select SM4_DECRYPT(FROM_BASE64('aDjwRflBrDjhBZIOFNw3Tg=='),'F3229A0B371ED2D9441B830D21A390C3');
+--------------------------------------------------------------------------------+
| sm4_decrypt(from_base64('aDjwRflBrDjhBZIOFNw3Tg=='), '***', '', 'SM4_128_ECB') |
+--------------------------------------------------------------------------------+
| text                                                                           |
+--------------------------------------------------------------------------------+
1 row in set (0.19 sec)

MySQL> set block_encryption_mode="SM4_128_CBC";
Query OK, 0 rows affected (0.006 sec)

mysql> select SM4_DECRYPT(FROM_BASE64('FSYstvOmH2cXy7B/072Mug=='),'F3229A0B371ED2D9441B830D21A390C3'); -- since 2.1.7
+--------------------------------------------------------------------------------+
| sm4_decrypt(from_base64('FSYstvOmH2cXy7B/072Mug=='), '***', '', 'SM4_128_CBC') |
+--------------------------------------------------------------------------------+
| text                                                                           |
+--------------------------------------------------------------------------------+
1 row in set (0.11 sec)

MySQL > select SM4_DECRYPT(FROM_BASE64('G7yqOKfEyxdagboz6Qf01A=='),'F3229A0B371ED2D9441B830D21A390C3', '0123456789');
+--------------------------------------------------------------------------------------------------------+
| sm4_decrypt(from_base64('G7yqOKfEyxdagboz6Qf01A=='), 'F3229A0B371ED2D9441B830D21A390C3', '0123456789') |
+--------------------------------------------------------------------------------------------------------+
| text                                                                                                   |
+--------------------------------------------------------------------------------------------------------+
1 row in set (0.012 sec)

Keywords

SM4_DECRYPT, SM4, DECRYPT