$cipher  = MCRYPT_RIJNDAEL_256;

$key     = 'La blanquette est bonne';    

$mode    = 'cbc';



function cryptage($data, $key,  $cipher, $mode){

    return base64_encode(mcrypt_encrypt($cipher, md5($key), $data, $mode, md5($key)));

}



function decryptage($data, $key,  $cipher, $mode){

    return rtrim(mcrypt_decrypt($cipher, md5($key), base64_decode($data), $mode, md5($key)));

}