Using NatsConnection in .c# core 8.0 with NKey

[Kurt-Callebaut]

Hi, i searched accros the internet , also used AI, but it seems i can't get to setup a connection in C#.
I have a SUA nkey that works in CLI, so server and authentication seems fine, but when i make a connections with Nats.net and add the nkey or nkey file, i keep getting an authentication error.

I also tried to convert to public key UDX... but the problem remains.

Anyone have a good example how this works ?

atm i use this :

`
using NATS.Client.Core;
using NATS.Client.JetStream.Models;
using NATS.Client.JetStream;
using NATS.Net;

....

            var opts = new NatsOpts
            {
                Url = serverUrl,
                Name = "My Reflex Server",
                AuthOpts = new NatsAuthOpts()
                {
                    NKey = MyKey,
                    // NKeyFile = "".. didnt work with SUA nkey in the file
                }
            };
            
            await using var connection = new NatsConnection(opts);

`
And this is/was my conversion from SUA to UDX public key

`
public static string ConvertSUAtoUDX(string suaSeed)
{
if (!suaSeed.StartsWith("SUA"))
throw new ArgumentException("Invalid SUA seed. It must start with 'SUA'.");

 // Decode the SUA seed to extract the Ed25519 private key (skip "SUA" prefix)
 byte[] decodedSeed = SimpleBase.Base32.Rfc4648.Decode(suaSeed.Substring(3)); // Remove "SUA" prefix
 byte[] ed25519Seed = decodedSeed.Skip(2).ToArray(); // Extract the 32-byte Ed25519 seed

 // Generate the Ed25519 public key from the private key
 var privateKey = new Ed25519PrivateKeyParameters(ed25519Seed, 0);
 var publicKey = privateKey.GeneratePublicKey();

 // Convert the public key to NKey format (UDX)
 return "UDX" + SimpleBase.Base32.Rfc4648.Encode(publicKey.GetEncoded()).Replace("=", ""); // Remove padding

}
`
All calls with private or public nkey result in : NATS.Client.Core.NatsServerException: Server error: Authorization Violation

( CLI connection works with the SUA nkey. )

Any help is appreciated. :)

[mtmk]

You need to provide the seed as well. have a look at the example in the tests:

nats.net/tests/NATS.Client.Core.Tests/NatsConnectionTest.Auth.cs

Lines 66 to 70 in 0450443

	AuthOpts = NatsAuthOpts.Default with
	{
	NKey = "UALQSMXRSAA7ZXIGDDJBJ2JOYJVQIWM3LQVDM5KYIPG4EP3FAGJ47BOJ",
	Seed = "SUAAVWRZG6M5FA5VRRGWSCIHKTOJC7EWNIT4JV3FTOIPO4OBFR5WA7X5TE",
	},

edit: sorry, what you have seems to be the seed, put that in Seed property and you need the NKey (which is the public key) as well then.

[Kurt-Callebaut]

Ok, thx for the quick response. Looking at this example, i realize the delivered nkey starting with "SUA... is actually the seed and i don't have the "UAL.." . i 'll see if i can get it using NKeys.FromSeed function... gonna give it a try... Thx.. :)

[Kurt-Callebaut]

NKeys.PublicKeyFromSeed(nKey); did the trick. thx again. 👍