function validateSignature( params )
{
    var md5hash = crypto.createHash('md5');
    var pp = [];
    for (k in params)
    {
        if (k != "sig")
        {
            pp.push(k + "=" + params[k])
        }
    }
    var res = pp.sort().join("") + g_config['secret'];

    var calculated_sig = md5hash.update( res, 'utf8').digest('hex');

    return (params.sig == calculated_sig);
}