Remove legacy AttackTracer repo content

src/OCSentinelCli/Transport/N8nUploadClient.cs

@@ -0,0 +1,70 @@
+using System.Net.Http.Headers;
+using System.Security.Cryptography;
+using System.Text;
+using OCSentinelCli.Models;
+
+namespace OCSentinelCli.Transport;
+
+internal sealed class N8nUploadClient
+{
+    public UploadResult UploadJson(
+        string webhookUrl,
+        string machineName,
+        string clientVersion,
+        string payloadJson,
+        string sharedSecret,
+        int timeoutSeconds)
+    {
+        string timestamp = DateTimeOffset.UtcNow.ToString("O");
+        string nonce = Guid.NewGuid().ToString("N");
+        string payloadHash = ComputeSha256(payloadJson);
+        string signature = ComputeSignature(machineName, timestamp, nonce, clientVersion, payloadHash, sharedSecret);
+
+        using var httpClient = new HttpClient
+        {
+            Timeout = TimeSpan.FromSeconds(Math.Max(5, timeoutSeconds))
+        };
+
+        using var request = new HttpRequestMessage(HttpMethod.Post, webhookUrl)
+        {
+            Content = new StringContent(payloadJson, Encoding.UTF8, "application/json")
+        };
+
+        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+        request.Headers.Add("X-ATN-Device", machineName);
+        request.Headers.Add("X-ATN-Timestamp", timestamp);
+        request.Headers.Add("X-ATN-Nonce", nonce);
+        request.Headers.Add("X-ATN-Version", clientVersion);
+        request.Headers.Add("X-ATN-Payload-SHA256", payloadHash);
+        request.Headers.Add("X-ATN-Signature", signature);
+
+        using HttpResponseMessage response = httpClient.Send(request);
+        string responseText = response.Content.ReadAsStringAsync().GetAwaiter().GetResult();
+
+        return new UploadResult
+        {
+            Success = response.IsSuccessStatusCode,
+            StatusCode = (int)response.StatusCode,
+            Message = string.IsNullOrWhiteSpace(responseText) ? response.ReasonPhrase ?? string.Empty : responseText,
+            Nonce = nonce,
+            PayloadSha256 = payloadHash
+        };
+    }
+
+    private static string ComputeSha256(string value)
+    {
+        byte[] bytes = Encoding.UTF8.GetBytes(value);
+        byte[] hash = SHA256.HashData(bytes);
+        return Convert.ToHexString(hash).ToLowerInvariant();
+    }
+
+    private static string ComputeSignature(string machineName, string timestamp, string nonce, string version, string payloadHash, string sharedSecret)
+    {
+        string canonical = string.Join("\n", machineName, timestamp, nonce, version, payloadHash);
+        byte[] secretBytes = Encoding.UTF8.GetBytes(sharedSecret);
+        byte[] canonicalBytes = Encoding.UTF8.GetBytes(canonical);
+        using var hmac = new HMACSHA256(secretBytes);
+        byte[] hash = hmac.ComputeHash(canonicalBytes);
+        return Convert.ToHexString(hash).ToLowerInvariant();
+    }
+}