// this script does the encryption:
function encrypt($stringArray, $key) {
	$s = strtr(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), serialize($stringArray), MCRYPT_MODE_CBC, md5(md5($key)))), '+/=', '-_,');
	return $s;
}

// This sets the variables writing to the database:
	$key = "key here";
	$connect = mysql_connect("db credentials");
	$db = mysql_select_db("dbname");
	$fullname = encrypt(mysql_real_escape_string($_POST["fullname"]));
	$surname = encrypt(mysql_real_escape_string($_POST["surname"]));
	$telephone = encrypt(mysql_real_escape_string($_POST["telephone"]));
	$email = encrypt(mysql_real_escape_string($_POST["email"]));

// This calls it from the database (obviously with the key as above)
function decrypt($stringArray, $key) {
	$s = unserialize(rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode(strtr($stringArray, '-_,', '+/=')), MCRYPT_MODE_CBC, md5(md5($key))), "\0"));
	return $s;
}