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src/__Libraries/StellaOps.Cryptography/CryptoProviderRegistry.cs

@@ -109,6 +109,33 @@ public sealed class CryptoProviderRegistry : ICryptoProviderRegistry
         return new CryptoSignerResolution(resolved, provider.Name);
     }
 
+    public CryptoHasherResolution ResolveHasher(string algorithmId, string? preferredProvider = null)
+    {
+        if (string.IsNullOrWhiteSpace(algorithmId))
+        {
+            throw new ArgumentException("Algorithm identifier is required.", nameof(algorithmId));
+        }
+
+        if (!string.IsNullOrWhiteSpace(preferredProvider) &&
+            providersByName.TryGetValue(preferredProvider!, out var hinted))
+        {
+            if (!hinted.Supports(CryptoCapability.ContentHashing, algorithmId))
+            {
+                throw new InvalidOperationException(
+                    $"Provider '{preferredProvider}' does not support content hashing with algorithm '{algorithmId}'.");
+            }
+
+            var hasher = hinted.GetHasher(algorithmId);
+            CryptoProviderMetrics.RecordProviderResolution(hinted.Name, CryptoCapability.ContentHashing, algorithmId);
+            return new CryptoHasherResolution(hasher, hinted.Name);
+        }
+
+        var provider = ResolveOrThrow(CryptoCapability.ContentHashing, algorithmId);
+        var resolved = provider.GetHasher(algorithmId);
+        CryptoProviderMetrics.RecordProviderResolution(provider.Name, CryptoCapability.ContentHashing, algorithmId);
+        return new CryptoHasherResolution(resolved, provider.Name);
+    }
+
     private IEnumerable<ICryptoProvider> EnumerateCandidates()
     {
         foreach (var name in preferredOrder)