Generate signed message in Kraken Rest api

Question

I am sending requests to Kraken api using a private key. The problem is, generated signature is not as expected.

Please note that the key you can see below it's just a sample. But it should generate the expected output. If so, that means the code is correct and it would work with an actual key.

The goal is to perform the following encryption:

HMAC-SHA512 of (URI path + SHA256(nonce + POST data)) and base64 decoded secret API key

So far, I've written this code:

public class KrakenApi
{
    private static string ApiPrivateKey = "kQH5HW/8p1uGOVjbgWA7FunAmGO8lsSUXNsu3eow76sz84Q18fWxnyRzBHCd3pd5nE9qa99HAZtuZuj6F1huXg==";

    public static string GetKrakenSignature(string urlPath, ulong nonce, Dictionary<string,string> data)
    {
        var hash256 = new SHA256Managed();
        var postData = string.Join("&", data.Select(e => e.Key + "=" + e.Value).ToArray());
        var encoded = Encoding.UTF8.GetBytes(nonce + postData);
        var message = Encoding.UTF8.GetBytes(urlPath).Concat(hash256.ComputeHash(encoded).ToArray());
        var secretDecoded = (System.Convert.FromBase64String(ApiPrivateKey));
        var hmacsha512 = new HMACSHA512(secretDecoded);
        var hash = hmacsha512.ComputeHash(secretDecoded.Concat(message).ToArray());
        return System.Convert.ToBase64String(hash);
    }
}

Usage:

var data = new Dictionary<string, string> {
    { "nonce", "1616492376594" },
    { "ordertype", "limit" },
    { "pair", "XBTUSD" },
    { "price", "37500" },
    { "type", "buy" },
    { "volume", "1.25" }
};

var signature = KrakenApi.GetKrakenSignature("/0/private/AddOrder", ulong.Parse(data["nonce"]), data);

Console.WriteLine(signature);

Output should be:

4/dpxb3iT4tp/ZCVEwSnEsLxx0bqyhLpdfOpc6fn7OR8+UClSV5n9E6aSS8MPtnRfp32bAb0nmbRn6H8ndwLUQ==

There are a number of code samples for Phyton, Node and Golang here that work correctly. But above code in C# not generating expected output.

Does your key contain '\' characters. I think you should at least put a `verbatim` in front of the string f.i. @";kjsdflkjasfljasflkjj"; — Paul Sinnema, Mar 23 '22 at 14:10
This code should produce expected output with the provided key, not with my private key. It doesn't seem there's a backslash there. — derloopkat, Mar 23 '22 at 14:19

score 2 · Accepted Answer · answered Mar 23 '22 at 21:50

This generates the expected output. Finally I've read Python documentation for each method used in the code sample and reproduced the same steps in C#.

public static string GetKrakenSignature(string urlPath, ulong nonce, Dictionary<string,string> data)
{
    var hash256 = new SHA256Managed();
    var postData = string.Join("&", data.Select(e => e.Key + "=" + e.Value).ToArray());
    var encoded = Encoding.UTF8.GetBytes(nonce + postData);
    var message = Encoding.UTF8.GetBytes(urlPath).Concat(hash256.ComputeHash(encoded)).ToArray();
    var mac = new HMACSHA512(Convert.FromBase64String(ApiPrivateKey));            
    return Convert.ToBase64String(mac.ComputeHash(message));
}

Generate signed message in Kraken Rest api

1 Answers1