Example of encrypted string Sign

Example of encrypted string Sign (PHP):

All fields are sorted by key value and then encrypted by md5 twice, sign=md5(md5(“key1=value1&key2=value2&$key”)) The encryption key is spliced directly after the string.

function makeSign(array $sign_arr, string $m_key): string {
    // Sort by key name in ascending order
    ksort($sign_arr);
    // Construct the query string uid=xxx&sid=xxx
    $str = http_build_query($sign_arr);
    // Splicing Key
    $str .= $m_key;
    // Double md5
    return md5(md5($str));
}

// Usage Examples
$sign_arr = [
    'uid' => $uid,
    'sid' => $sid,
];
$m_key = "1234567890";

$sign = makeSign($sign_arr, $m_key);
echo $sign;