MariaDB [(none)]> show status like 'Ssl_cipher';
+---------------+---------------------------+
| Variable_name | Value |
+---------------+---------------------------+
| Ssl_cipher | DHE-RSA-AES256-GCM-SHA384 |
+---------------+---------------------------+
1 row in set (0.01 sec)
MariaDB [(none)]> select aes_decrypt('MySQL','adf');
+----------------------------+
| aes_decrypt('MySQL','adf') |
+----------------------------+
| NULL |
+----------------------------+
1 row in set (0.00 sec)
MariaDB [(none)]> select aes_decrypt('MySQL','adf');
ERROR 2013 (HY000): Lost connection to MySQL server during query