stabilizaiton work - projects rework for maintenanceability and ui livening

src/__Libraries/StellaOps.Auth.Security/Dpop/DpopProofValidator.Signature.cs

@@ -0,0 +1,34 @@
+using Microsoft.Extensions.Logging;
+using Microsoft.IdentityModel.Tokens;
+using System.Linq;
+
+namespace StellaOps.Auth.Security.Dpop;
+
+public sealed partial class DpopProofValidator
+{
+    private DpopValidationResult? ValidateSignature(string proof, DpopProofHeader header)
+    {
+        try
+        {
+            var parameters = new TokenValidationParameters
+            {
+                ValidateAudience = false,
+                ValidateIssuer = false,
+                ValidateLifetime = false,
+                ValidateTokenReplay = false,
+                RequireSignedTokens = true,
+                ValidateIssuerSigningKey = true,
+                IssuerSigningKey = header.Key,
+                ValidAlgorithms = _options.NormalizedAlgorithms.ToArray()
+            };
+
+            _tokenHandler.ValidateToken(proof, parameters, out _);
+            return null;
+        }
+        catch (Exception ex)
+        {
+            _logger?.LogWarning(ex, "DPoP proof signature validation failed.");
+            return DpopValidationResult.Failure("invalid_signature", "DPoP proof signature validation failed.");
+        }
+    }
+}