Better circuit ids (#10688)

* Better circuit ids.
* Generates cryptographically strong circuit ids.
  * 32 bits of entropy from a PRNG.
  * DataProtected for authenticated encryption.

src/Components/Server/ref/Microsoft.AspNetCore.Components.Server.csproj

@@ -6,6 +6,7 @@
   <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0'">
     <Compile Include="Microsoft.AspNetCore.Components.Server.netcoreapp3.0.cs" />
     <Reference Include="Microsoft.AspNetCore.Components.Browser"  />
+    <Reference Include="Microsoft.AspNetCore.DataProtection"  />
     <Reference Include="Microsoft.Extensions.Logging"  />
     <Reference Include="Microsoft.AspNetCore.SignalR"  />
     <Reference Include="Microsoft.AspNetCore.StaticFiles"  />

src/Components/Server/src/CircuitOptions.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.AspNetCore.DataProtection;
 
 namespace Microsoft.AspNetCore.Components.Server
 {

src/Components/Server/src/Circuits/CircuitHost.cs

@@ -50,6 +50,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public event UnhandledExceptionEventHandler UnhandledException;
 
         public CircuitHost(
+            string circuitId,
             IServiceScope scope,
             CircuitClientProxy client,
             RendererRegistry rendererRegistry,
@@ -60,6 +61,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
             CircuitHandler[] circuitHandlers,
             ILogger logger)
         {
+            CircuitId = circuitId;
             _scope = scope ?? throw new ArgumentNullException(nameof(scope));
             Dispatcher = dispatcher;
             Client = client;
@@ -78,7 +80,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
             Renderer.UnhandledSynchronizationException += SynchronizationContext_UnhandledException;
         }
 
-        public string CircuitId { get; } = Guid.NewGuid().ToString();
+        public string CircuitId { get; }
 
         public Circuit Circuit { get; }
 

src/Components/Server/src/Circuits/CircuitIdFactory.cs

@@ -0,0 +1,57 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Security.Cryptography;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.AspNetCore.Components.Server.Circuits
+{
+    // This is a singleton instance
+    // Generates strong cryptographic ids for circuits that are protected with authenticated encryption.
+    internal class CircuitIdFactory
+    {
+        private const string CircuitIdProtectorPurpose = "Microsoft.AspNetCore.Components.Server";
+
+        private readonly RandomNumberGenerator _generator = RandomNumberGenerator.Create();
+        private readonly IDataProtector _protector;
+
+        public CircuitIdFactory(IDataProtectionProvider provider)
+        {
+            _protector = provider.CreateProtector(CircuitIdProtectorPurpose);
+        }
+
+        // Generates a circuit id that is produced from a strong cryptographic random number generator
+        // we don't care about the underlying payload, other than its uniqueness and the fact that we
+        // authenticate encrypt it using data protection.
+        // For validation, the fact that we can unprotect the payload is guarantee enough.
+        public string CreateCircuitId()
+        {
+            var buffer = new byte[32];
+            _generator.GetBytes(buffer);
+            var payload = _protector.Protect(buffer);
+
+            return Base64UrlTextEncoder.Encode(payload);
+        }
+
+        public bool ValidateCircuitId(string circuitId)
+        {
+            try
+            {
+                var protectedBytes = Base64UrlTextEncoder.Decode(circuitId);
+                _protector.Unprotect(protectedBytes);
+
+                // Its enough that we prove that we can unprotect the payload to validate the circuit id,
+                // as this demonstrates that it the id wasn't tampered with.
+                return true;
+            }
+            catch (Exception)
+            {
+                // The payload format is not correct (either not base64urlencoded or not data protected)
+                return false;
+            }
+        }
+    }
+}

src/Components/Server/src/Circuits/CircuitRegistry.cs

@@ -6,7 +6,6 @@ using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Components.Rendering;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Logging;
@@ -41,15 +40,17 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         private readonly object CircuitRegistryLock = new object();
         private readonly CircuitOptions _options;
         private readonly ILogger _logger;
+        private readonly CircuitIdFactory _circuitIdFactory;
         private readonly PostEvictionCallbackRegistration _postEvictionCallback;
 
         public CircuitRegistry(
             IOptions<CircuitOptions> options,
-            ILogger<CircuitRegistry> logger)
+            ILogger<CircuitRegistry> logger,
+            CircuitIdFactory circuitIdFactory)
         {
             _options = options.Value;
             _logger = logger;
-
+            _circuitIdFactory = circuitIdFactory;
             ConnectedCircuits = new ConcurrentDictionary<string, CircuitHost>(StringComparer.Ordinal);
 
             DisconnectedCircuits = new MemoryCache(new MemoryCacheOptions
@@ -139,6 +140,11 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
 
         public virtual async Task<CircuitHost> ConnectAsync(string circuitId, IClientProxy clientProxy, string connectionId, CancellationToken cancellationToken)
         {
+            if (!_circuitIdFactory.ValidateCircuitId(circuitId))
+            {
+                return null;
+            }
+
             CircuitHost circuitHost;
             bool previouslyConnected;
 

src/Components/Server/src/Circuits/DefaultCircuitFactory.cs

@@ -21,13 +21,16 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
     {
         private readonly IServiceScopeFactory _scopeFactory;
         private readonly ILoggerFactory _loggerFactory;
+        private readonly CircuitIdFactory _circuitIdFactory;
 
         public DefaultCircuitFactory(
             IServiceScopeFactory scopeFactory,
-            ILoggerFactory loggerFactory)
+            ILoggerFactory loggerFactory,
+            CircuitIdFactory circuitIdFactory)
         {
             _scopeFactory = scopeFactory ?? throw new ArgumentNullException(nameof(scopeFactory));
             _loggerFactory = loggerFactory;
+            _circuitIdFactory = circuitIdFactory ?? throw new ArgumentNullException(nameof(circuitIdFactory));
         }
 
         public override CircuitHost CreateCircuitHost(
@@ -81,6 +84,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
                 .ToArray();
 
             var circuitHost = new CircuitHost(
+                _circuitIdFactory.CreateCircuitId(),
                 scope,
                 client,
                 rendererRegistry,

src/Components/Server/src/DependencyInjection/ComponentServiceCollectionExtensions.cs

@@ -28,6 +28,8 @@ namespace Microsoft.Extensions.DependencyInjection
         {
             var builder = new DefaultServerSideBlazorBuilder(services);
 
+            services.AddDataProtection();
+
             // This call INTENTIONALLY uses the AddHubOptions on the SignalR builder, because it will merge
             // the global HubOptions before running the configure callback. We want to ensure that happens
             // once. Our AddHubOptions method doesn't do this.
@@ -51,6 +53,9 @@ namespace Microsoft.Extensions.DependencyInjection
             // Components entrypoints, this lot is the same and repeated registrations are a no-op.
             services.TryAddEnumerable(ServiceDescriptor.Singleton<IPostConfigureOptions<StaticFileOptions>, ConfigureStaticFilesOptions>());
             services.TryAddSingleton<CircuitFactory, DefaultCircuitFactory>();
+
+            services.TryAddSingleton<CircuitIdFactory>();
+
             services.TryAddScoped(s => s.GetRequiredService<ICircuitAccessor>().Circuit);
             services.TryAddScoped<ICircuitAccessor, DefaultCircuitAccessor>();
 

src/Components/Server/src/Microsoft.AspNetCore.Components.Server.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>netcoreapp3.0</TargetFramework>
@@ -13,6 +13,7 @@
 
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Components.Browser" />
+    <Reference Include="Microsoft.AspNetCore.DataProtection" />
     <Reference Include="Microsoft.Extensions.Logging" />
     <Reference Include="Microsoft.AspNetCore.SignalR" />
     <Reference Include="Microsoft.AspNetCore.StaticFiles" />
@@ -52,10 +53,7 @@
   <ItemGroup>
     <EmbeddedResource Include="..\..\Browser.JS\dist\$(Configuration)\blazor.server.js" LogicalName="_framework/%(Filename)%(Extension)" />
 
-    <EmbeddedResource
-      Include="..\..\Browser.JS\dist\$(Configuration)\blazor.server.js.map"
-      LogicalName="_framework/%(Filename)%(Extension)"
-      Condition="Exists('..\..\Browser.JS\dist\$(Configuration)\blazor.server.js.map')" />
+    <EmbeddedResource Include="..\..\Browser.JS\dist\$(Configuration)\blazor.server.js.map" LogicalName="_framework/%(Filename)%(Extension)" Condition="Exists('..\..\Browser.JS\dist\$(Configuration)\blazor.server.js.map')" />
   </ItemGroup>
 
 </Project>

src/Components/Server/test/Circuits/CircuitHostTest.cs

@@ -28,6 +28,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
             var serviceScope = new Mock<IServiceScope>();
             var remoteRenderer = GetRemoteRenderer(Renderer.CreateDefaultDispatcher());
             var circuitHost = TestCircuitHost.Create(
+                Guid.NewGuid().ToString(),
                 serviceScope.Object,
                 remoteRenderer);
 
@@ -46,6 +47,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
             var serviceScope = new Mock<IServiceScope>();
             var remoteRenderer = GetRemoteRenderer(Renderer.CreateDefaultDispatcher());
             var circuitHost = TestCircuitHost.Create(
+                Guid.NewGuid().ToString(),
                 serviceScope.Object,
                 remoteRenderer);
 

src/Components/Server/test/Circuits/CircuitIdFactoryTest.cs

@@ -0,0 +1,89 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Linq;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.WebUtilities;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Components.Server.Circuits
+{
+    public class CircuitIdFactoryTest
+    {
+        [Fact]
+        public void CreateCircuitId_Generates_NewRandomId()
+        {
+            var factory = TestCircuitIdFactory.CreateTestFactory();
+
+            // Act
+            var id = factory.CreateCircuitId();
+
+            // Assert
+            Assert.NotNull(id);
+            // This is the magic data protection header that validates its protected
+            Assert.StartsWith("CfDJ", id);
+        }
+
+        [Fact]
+        public void CreateCircuitId_Generates_GeneratesDifferentIds_ForSuccesiveCalls()
+        {
+            // Arrange
+            var factory = TestCircuitIdFactory.CreateTestFactory();
+
+            // Act
+            var ids = Enumerable.Range(0, 100).Select(i => factory.CreateCircuitId()).ToArray();
+
+            // Assert
+            Assert.All(ids, id => Assert.NotNull(id));
+            Assert.Equal(100, ids.Distinct(StringComparer.Ordinal).Count());
+        }
+
+        [Fact]
+        public void CircuitIds_Roundtrip()
+        {
+            // Arrange
+            var factory = TestCircuitIdFactory.CreateTestFactory();
+            var id = factory.CreateCircuitId();
+
+            // Act
+            var isValid = factory.ValidateCircuitId(id);
+
+            // Assert
+            Assert.True(isValid, "Failed to validate id");
+        }
+
+        [Fact]
+        public void ValidateCircuitId_ReturnsFalseForMalformedPayloads()
+        {
+            // Arrange
+            var factory = TestCircuitIdFactory.CreateTestFactory();
+
+            // Act
+            var isValid = factory.ValidateCircuitId("$%@&==");
+
+            // Assert
+            Assert.False(isValid, "Accepted an invalid payload");
+        }
+
+        [Fact]
+        public void ValidateCircuitId_ReturnsFalseForPotentiallyTamperedPayloads()
+        {
+            // Arrange
+            var factory = TestCircuitIdFactory.CreateTestFactory();
+            var id = factory.CreateCircuitId();
+            var protectedBytes = Base64UrlTextEncoder.Decode(id);
+            for (int i = protectedBytes.Length - 10; i < protectedBytes.Length; i++)
+            {
+                protectedBytes[i] = 0;
+            }
+            var tamperedId = Base64UrlTextEncoder.Encode(protectedBytes);
+
+            // Act
+            var isValid = factory.ValidateCircuitId(tamperedId);
+
+            // Assert
+            Assert.False(isValid, "Accepted a tampered payload");
+        }
+    }
+}

src/Components/Server/test/Circuits/CircuitPrerendererTest.cs

@@ -35,7 +35,10 @@ namespace Microsoft.AspNetCore.Components.Server.Tests.Circuits
         {
             // Arrange
             var circuitFactory = new TestCircuitFactory();
-            var circuitRegistry = new CircuitRegistry(Options.Create(new CircuitOptions()), Mock.Of<ILogger<CircuitRegistry>>());
+            var circuitRegistry = new CircuitRegistry(
+                Options.Create(new CircuitOptions()),
+                Mock.Of<ILogger<CircuitRegistry>>(),
+                TestCircuitIdFactory.CreateTestFactory());
             var circuitPrerenderer = new CircuitPrerenderer(circuitFactory, circuitRegistry);
             var httpContext = new DefaultHttpContext();
             var httpRequest = httpContext.Request;
@@ -76,7 +79,10 @@ namespace Microsoft.AspNetCore.Components.Server.Tests.Circuits
         {
             // Arrange
             var circuitFactory = new TestCircuitFactory();
-            var circuitRegistry = new CircuitRegistry(Options.Create(new CircuitOptions()), Mock.Of<ILogger<CircuitRegistry>>());
+            var circuitRegistry = new CircuitRegistry(
+                Options.Create(new CircuitOptions()),
+                Mock.Of<ILogger<CircuitRegistry>>(),
+                TestCircuitIdFactory.CreateTestFactory());
             var circuitPrerenderer = new CircuitPrerenderer(circuitFactory, circuitRegistry);
             var httpContext = new DefaultHttpContext();
             var httpRequest = httpContext.Request;
@@ -117,7 +123,7 @@ namespace Microsoft.AspNetCore.Components.Server.Tests.Circuits
                     return uriHelper;
                 });
                 var serviceScope = serviceCollection.BuildServiceProvider().CreateScope();
-                return TestCircuitHost.Create(serviceScope);
+                return TestCircuitHost.Create(Guid.NewGuid().ToString(), serviceScope);
             }
         }
 

src/Components/Server/test/Circuits/CircuitRegistryTest.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.DataProtection;
 using Microsoft.AspNetCore.SignalR;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -34,8 +35,10 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task ConnectAsync_TransfersClientOnActiveCircuit()
         {
             // Arrange
-            var registry = CreateRegistry();
-            var circuitHost = TestCircuitHost.Create();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+
+            var registry = CreateRegistry(circuitIdFactory);
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId());
             registry.Register(circuitHost);
 
             var newClient = Mock.Of<IClientProxy>();
@@ -57,8 +60,10 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task ConnectAsync_MakesInactiveCircuitActive()
         {
             // Arrange
-            var registry = CreateRegistry();
-            var circuitHost = TestCircuitHost.Create();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+
+            var registry = CreateRegistry(circuitIdFactory);
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId());
             registry.DisconnectedCircuits.Set(circuitHost.CircuitId, circuitHost, new MemoryCacheEntryOptions { Size = 1 });
 
             var newClient = Mock.Of<IClientProxy>();
@@ -81,9 +86,10 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task ConnectAsync_InvokesCircuitHandlers_WhenCircuitWasPreviouslyDisconnected()
         {
             // Arrange
-            var registry = CreateRegistry();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+            var registry = CreateRegistry(circuitIdFactory);
             var handler = new Mock<CircuitHandler> { CallBase = true };
-            var circuitHost = TestCircuitHost.Create(handlers: new[] { handler.Object });
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId(), handlers: new[] { handler.Object });
             registry.DisconnectedCircuits.Set(circuitHost.CircuitId, circuitHost, new MemoryCacheEntryOptions { Size = 1 });
 
             var newClient = Mock.Of<IClientProxy>();
@@ -104,9 +110,10 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task ConnectAsync_InvokesCircuitHandlers_WhenCircuitWasConsideredConnected()
         {
             // Arrange
-            var registry = CreateRegistry();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+            var registry = CreateRegistry(circuitIdFactory);
             var handler = new Mock<CircuitHandler> { CallBase = true };
-            var circuitHost = TestCircuitHost.Create(handlers: new[] { handler.Object });
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId(), handlers: new[] { handler.Object });
             registry.Register(circuitHost);
 
             var newClient = Mock.Of<IClientProxy>();
@@ -199,11 +206,13 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task Connect_WhileDisconnectIsInProgress()
         {
             // Arrange
-            var registry = new TestCircuitRegistry();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+
+            var registry = new TestCircuitRegistry(circuitIdFactory);
             registry.BeforeDisconnect = new ManualResetEventSlim();
             var tcs = new TaskCompletionSource<int>();
 
-            var circuitHost = TestCircuitHost.Create();
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId());
             registry.Register(circuitHost);
             var client = Mock.Of<IClientProxy>();
             var newId = "new-connection";
@@ -238,13 +247,15 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task Connect_WhileDisconnectIsInProgress_SeriallyExecutesCircuitHandlers()
         {
             // Arrange
-            var registry = new TestCircuitRegistry();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+
+            var registry = new TestCircuitRegistry(circuitIdFactory);
             registry.BeforeDisconnect = new ManualResetEventSlim();
             // This verifies that connection up \ down events on a circuit handler are always invoked serially.
             var circuitHandler = new SerialCircuitHandler();
             var tcs = new TaskCompletionSource<int>();
 
-            var circuitHost = TestCircuitHost.Create(handlers: new[] { circuitHandler });
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId(), handlers: new[] { circuitHandler });
             registry.Register(circuitHost);
             var client = Mock.Of<IClientProxy>();
             var newId = "new-connection";
@@ -276,9 +287,11 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         public async Task DisconnectWhenAConnectIsInProgress()
         {
             // Arrange
-            var registry = new TestCircuitRegistry();
+            var circuitIdFactory = TestCircuitIdFactory.CreateTestFactory();
+
+            var registry = new TestCircuitRegistry(circuitIdFactory);
             registry.BeforeConnect = new ManualResetEventSlim();
-            var circuitHost = TestCircuitHost.Create();
+            var circuitHost = TestCircuitHost.Create(circuitIdFactory.CreateCircuitId());
             registry.Register(circuitHost);
             var client = Mock.Of<IClientProxy>();
             var oldId = circuitHost.Client.ConnectionId;
@@ -302,8 +315,8 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
 
         private class TestCircuitRegistry : CircuitRegistry
         {
-            public TestCircuitRegistry()
-                : base(Options.Create(new CircuitOptions()), NullLogger<CircuitRegistry>.Instance)
+            public TestCircuitRegistry(CircuitIdFactory factory)
+                : base(Options.Create(new CircuitOptions()), NullLogger<CircuitRegistry>.Instance, factory)
             {
             }
 
@@ -331,11 +344,12 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
             }
         }
 
-        private static CircuitRegistry CreateRegistry()
+        private static CircuitRegistry CreateRegistry(CircuitIdFactory factory = null)
         {
             return new CircuitRegistry(
                 Options.Create(new CircuitOptions()),
-                NullLogger<CircuitRegistry>.Instance);
+                NullLogger<CircuitRegistry>.Instance,
+                factory ?? TestCircuitIdFactory.CreateTestFactory());
         }
 
         private class SerialCircuitHandler : CircuitHandler

src/Components/Server/test/Circuits/TestCircuitHost.cs

@@ -18,8 +18,8 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
 {
     internal class TestCircuitHost : CircuitHost
     {
-        private TestCircuitHost(IServiceScope scope, CircuitClientProxy client, RendererRegistry rendererRegistry, RemoteRenderer renderer, IList<ComponentDescriptor> descriptors, IDispatcher dispatcher, RemoteJSRuntime jsRuntime, CircuitHandler[] circuitHandlers, ILogger logger)
-            : base(scope, client, rendererRegistry, renderer, descriptors, dispatcher, jsRuntime, circuitHandlers, logger)
+        private TestCircuitHost(string circuitId, IServiceScope scope, CircuitClientProxy client, RendererRegistry rendererRegistry, RemoteRenderer renderer, IList<ComponentDescriptor> descriptors, IDispatcher dispatcher, RemoteJSRuntime jsRuntime, CircuitHandler[] circuitHandlers, ILogger logger)
+            : base(circuitId, scope, client, rendererRegistry, renderer, descriptors, dispatcher, jsRuntime, circuitHandlers, logger)
         {
         }
 
@@ -29,6 +29,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
         }
 
         public static CircuitHost Create(
+            string circuitId = null,
             IServiceScope serviceScope = null,
             RemoteRenderer remoteRenderer = null,
             CircuitHandler[] handlers = null,
@@ -54,6 +55,7 @@ namespace Microsoft.AspNetCore.Components.Server.Circuits
 
             handlers = handlers ?? Array.Empty<CircuitHandler>();
             return new TestCircuitHost(
+                circuitId ?? Guid.NewGuid().ToString(),
                 serviceScope,
                 clientProxy,
                 renderRegistry,

src/Components/Server/test/Circuits/TestCircuitIdFactory.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.DataProtection;
+
+namespace Microsoft.AspNetCore.Components.Server.Circuits
+{
+    internal class TestCircuitIdFactory
+    {
+        public static CircuitIdFactory CreateTestFactory()
+        {
+            return new CircuitIdFactory(new EphemeralDataProtectionProvider());
+        }
+    }
+}

src/Mvc/Mvc.Components.Prerendering/test/HtmlHelperComponentPrerenderingExtensionsTests.cs

@@ -432,6 +432,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         {
             var services = new ServiceCollection();
             services.AddLogging();
+            services.AddDataProtection();
             services.AddSingleton(HtmlEncoder.Default);
             configureServices = configureServices ?? (s => s.AddServerSideBlazor());
             configureServices?.Invoke(services);