Fix trimming warning

src/DataProtection/DataProtection/src/AuthenticatedEncryption/ManagedAuthenticatedEncryptorFactory.cs

@@ -74,7 +74,7 @@ public sealed class ManagedAuthenticatedEncryptorFactory : IAuthenticatedEncrypt
         }
         else
         {
-            return AlgorithmActivator.CreateFactory<KeyedHashAlgorithm>(configuration.ValidationAlgorithmType);
+            return AlgorithmActivator.CreateFactory<KeyedHashAlgorithm>(ValidateHasPublicParameterlessConstructor(configuration.ValidationAlgorithmType));
         }
     }
 
@@ -99,10 +99,23 @@ public sealed class ManagedAuthenticatedEncryptorFactory : IAuthenticatedEncrypt
         }
         else
         {
-            return AlgorithmActivator.CreateFactory<SymmetricAlgorithm>(configuration.EncryptionAlgorithmType);
+            return AlgorithmActivator.CreateFactory<SymmetricAlgorithm>(ValidateHasPublicParameterlessConstructor(configuration.EncryptionAlgorithmType));
         }
     }
 
+    [UnconditionalSuppressMessage("Trimmer", "IL2068", Justification = "Reflecting over the async Task types contract")]
+    [UnconditionalSuppressMessage("Trimmer", "IL2070", Justification = "Reflecting over the async Task types contract")]
+    [return: DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)]
+    private static Type ValidateHasPublicParameterlessConstructor(Type type)
+    {
+        if (type.GetConstructor(Type.EmptyTypes) == null)
+        {
+            throw new InvalidOperationException($"Unable to find public parameterless constructor for type '{type.FullName}'. If the app is published with trimming then it may have been trimmed. Ensure the type's assembly is excluded from trimming.");
+        }
+
+        return type;
+    }
+
     /// <summary>
     /// Contains helper methods for generating cryptographic algorithm factories.
     /// </summary>
@@ -111,7 +124,7 @@ public sealed class ManagedAuthenticatedEncryptorFactory : IAuthenticatedEncrypt
         /// <summary>
         /// Creates a factory that wraps a call to <see cref="Activator.CreateInstance{T}"/>.
         /// </summary>
-        public static Func<T> CreateFactory<T>(Type implementation)
+        public static Func<T> CreateFactory<T>([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)] Type implementation)
         {
             return ((IActivator<T>)Activator.CreateInstance(typeof(AlgorithmActivatorCore<>).MakeGenericType(implementation))!).Creator;
         }