Signature Algorithm

Step One

• All the paramters sent to the server is treated as a key-value Map. Sort the map M by the ASCII values of keys in ascending order(0->9,a->z,A->Z).
• Concatenate them into a string named stringA using the URL key-value pair format (i.e., key1=value1&key2=value2…).
• add &key=secret_key at the end of the StringA
• the whole StringA is like "key1=value1&key2=value2&key={your_secret_key}"

Please pay Special Attention to the following important rules:

• make sure all values in key-values pair are non-empty, if some value is empty, remove this key-value from the Map;
• Parameter names are sorted in ascending order by their ASCII values (0->9,a->z,A->Z);
• Parameter names are case-sensitive;

Step Two

Calculate the MD5 hashed value on stringA, and convert the md5 hashed value to uppercase, add the md5_hashed_value into the original M-map within the key named sign={md5_hashed_value}

• the whole map is like :

$params = [
    "key1"=>"value1",
    "key2"=>"value2",
    "key3"=>"value3",
    "sign"=>"{md5_hashed_value}"
]

Md5 signautre sample Code

function md5_sign($data,$key){
    ksort($data);
    $string = http_build_query($data);
    $string = urldecode($string); 
    $string=trim($string) . "&key=" . $key;
    return strtoupper(md5($string));
}