MySQL/SQL Server vs. PHP encryption -

according documentation, most-secured encryption methods are:

aes_encrypt() mysql

encryptbypassphrase() sql server

mc_encrypt() php

which 1 should used?

recently on many blogs , e-magazines being posted information, pre-encryption php best way, since if my/sql server compromised, attacker can scan logs.

example of mcrypt pre-encrypting string before database insertion (vs others):

<?php define('encryption_key', '555d6c18e7b8aa109bfda854df942088a9984cccf2a979bd21b99e50aedc1976');  function cryp($action, $string, $key) {     $key = pack('h*', $key);      if($action == 'en') {         $string = serialize($string);         $iv = mcrypt_create_iv(mcrypt_get_iv_size(mcrypt_rijndael_256, mcrypt_mode_cbc), mcrypt_dev_urandom);         $string = base64_encode(mcrypt_encrypt(mcrypt_rijndael_256, $key, $string . hash_hmac('sha256', $string, substr(bin2hex($key), -32)), mcrypt_mode_cbc, $iv)) . '|' . base64_encode($iv);     }      if($action == 'de') {         $string = explode('|', $string);         $iv = base64_decode($string[1]);         $string = unserialize(substr(trim(mcrypt_decrypt(mcrypt_rijndael_256, $key, base64_decode($string[0]), mcrypt_mode_cbc, $iv)), 0, -64));     }      return $string; }  $data = 'sample string here';  $encrypted = cryp('en', $data, encryption_key); $decrypted = cryp('de', $encrypted, encryption_key);  echo $encrypted; ?>