File: KeyManagement\KeyRingBasedDataProtectorTests.cs
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Project: src\src\DataProtection\DataProtection\test\Microsoft.AspNetCore.DataProtection.Tests\Microsoft.AspNetCore.DataProtection.Tests.csproj (Microsoft.AspNetCore.DataProtection.Tests)
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Globalization;
using System.Net;
using System.Text;
using Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption;
using Microsoft.AspNetCore.DataProtection.AuthenticatedEncryption.ConfigurationModel;
using Microsoft.AspNetCore.DataProtection.KeyManagement.Internal;
using Microsoft.AspNetCore.InternalTesting;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Moq;
 
namespace Microsoft.AspNetCore.DataProtection.KeyManagement;
 
public class KeyRingBasedDataProtectorTests
{
    [Fact]
    public void Protect_NullPlaintext_Throws()
    {
        // Arrange
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: new Mock<IKeyRingProvider>().Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        ExceptionAssert.ThrowsArgumentNull(() => protector.Protect(plaintext: null), "plaintext");
    }
 
    [Fact]
    public void Protect_EncryptsToDefaultProtector_MultiplePurposes()
    {
        // Arrange
        Guid defaultKey = new Guid("ba73c9ce-d322-4e45-af90-341307e11c38");
        byte[] expectedPlaintext = new byte[] { 0x03, 0x05, 0x07, 0x11, 0x13, 0x17, 0x19 };
        byte[] expectedAad = BuildAadFromPurposeStrings(defaultKey, "purpose1", "purpose2", "yet another purpose");
        byte[] expectedProtectedData = BuildProtectedDataFromCiphertext(defaultKey, new byte[] { 0x23, 0x29, 0x31, 0x37 });
 
        var mockEncryptor = new Mock<IAuthenticatedEncryptor>();
        mockEncryptor
            .Setup(o => o.Encrypt(It.IsAny<ArraySegment<byte>>(), It.IsAny<ArraySegment<byte>>()))
            .Returns<ArraySegment<byte>, ArraySegment<byte>>((actualPlaintext, actualAad) =>
            {
                Assert.Equal(expectedPlaintext, actualPlaintext.AsSpan());
                Assert.Equal(expectedAad, actualAad.AsSpan());
                return new byte[] { 0x23, 0x29, 0x31, 0x37 }; // ciphertext + tag
            });
 
        var mockKeyRing = new Mock<IKeyRing>(MockBehavior.Strict);
        mockKeyRing.Setup(o => o.DefaultKeyId).Returns(defaultKey);
        mockKeyRing.Setup(o => o.DefaultAuthenticatedEncryptor).Returns(mockEncryptor.Object);
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(mockKeyRing.Object);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: new[] { "purpose1", "purpose2" },
            newPurpose: "yet another purpose");
 
        // Act
        byte[] retVal = protector.Protect(expectedPlaintext);
 
        // Assert
        Assert.Equal(expectedProtectedData, retVal);
    }
 
    [Fact]
    public void Protect_EncryptsToDefaultProtector_SinglePurpose()
    {
        // Arrange
        Guid defaultKey = new Guid("ba73c9ce-d322-4e45-af90-341307e11c38");
        byte[] expectedPlaintext = new byte[] { 0x03, 0x05, 0x07, 0x11, 0x13, 0x17, 0x19 };
        byte[] expectedAad = BuildAadFromPurposeStrings(defaultKey, "single purpose");
        byte[] expectedProtectedData = BuildProtectedDataFromCiphertext(defaultKey, new byte[] { 0x23, 0x29, 0x31, 0x37 });
 
        var mockEncryptor = new Mock<IAuthenticatedEncryptor>();
        mockEncryptor
            .Setup(o => o.Encrypt(It.IsAny<ArraySegment<byte>>(), It.IsAny<ArraySegment<byte>>()))
            .Returns<ArraySegment<byte>, ArraySegment<byte>>((actualPlaintext, actualAad) =>
            {
                Assert.Equal(expectedPlaintext, actualPlaintext.AsSpan());
                Assert.Equal(expectedAad, actualAad.AsSpan());
                return new byte[] { 0x23, 0x29, 0x31, 0x37 }; // ciphertext + tag
            });
 
        var mockKeyRing = new Mock<IKeyRing>(MockBehavior.Strict);
        mockKeyRing.Setup(o => o.DefaultKeyId).Returns(defaultKey);
        mockKeyRing.Setup(o => o.DefaultAuthenticatedEncryptor).Returns(mockEncryptor.Object);
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(mockKeyRing.Object);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: new string[0],
            newPurpose: "single purpose");
 
        // Act
        byte[] retVal = protector.Protect(expectedPlaintext);
 
        // Assert
        Assert.Equal(expectedProtectedData, retVal);
    }
 
    [Fact]
    public void Protect_HomogenizesExceptionsToCryptographicException()
    {
        // Arrange
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: new Mock<IKeyRingProvider>(MockBehavior.Strict).Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Protect(new byte[0]));
        Assert.IsAssignableFrom<MockException>(ex.InnerException);
    }
 
    [Fact]
    public void Unprotect_NullProtectedData_Throws()
    {
        // Arrange
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: new Mock<IKeyRingProvider>().Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        ExceptionAssert.ThrowsArgumentNull(() => protector.Unprotect(protectedData: null), "protectedData");
    }
 
    [Fact]
    public void Unprotect_PayloadTooShort_ThrowsBadMagicHeader()
    {
        // Arrange
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: new Mock<IKeyRingProvider>().Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        byte[] badProtectedPayload = BuildProtectedDataFromCiphertext(Guid.NewGuid(), new byte[0]);
        badProtectedPayload = badProtectedPayload.Take(badProtectedPayload.Length - 1).ToArray(); // chop off the last byte
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(badProtectedPayload));
        Assert.Equal(Resources.ProtectionProvider_BadMagicHeader, ex.Message);
    }
 
    [Fact]
    public void Unprotect_PayloadHasBadMagicHeader_ThrowsBadMagicHeader()
    {
        // Arrange
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: new Mock<IKeyRingProvider>().Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        byte[] badProtectedPayload = BuildProtectedDataFromCiphertext(Guid.NewGuid(), new byte[0]);
        badProtectedPayload[0]++; // corrupt the magic header
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(badProtectedPayload));
        Assert.Equal(Resources.ProtectionProvider_BadMagicHeader, ex.Message);
    }
 
    [Fact]
    public void Unprotect_PayloadHasIncorrectVersionMarker_ThrowsNewerVersion()
    {
        // Arrange
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: new Mock<IKeyRingProvider>().Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        byte[] badProtectedPayload = BuildProtectedDataFromCiphertext(Guid.NewGuid(), new byte[0]);
        badProtectedPayload[3]++; // bump the version payload
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(badProtectedPayload));
        Assert.Equal(Resources.ProtectionProvider_BadVersion, ex.Message);
    }
 
    [Fact]
    public void Unprotect_KeyNotFound_ThrowsKeyNotFound()
    {
        // Arrange
        Guid notFoundKeyId = new Guid("654057ab-2491-4471-a72a-b3b114afda38");
        byte[] protectedData = BuildProtectedDataFromCiphertext(
            keyId: notFoundKeyId,
            ciphertext: new byte[0]);
 
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(new Mock<IAuthenticatedEncryptor>().Object);
        var encryptorFactory = new AuthenticatedEncryptorFactory(NullLoggerFactory.Instance);
 
        // the keyring has only one key
        Key key = new Key(Guid.Empty, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing = new KeyRing(key, new[] { key });
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(keyRing);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(protectedData));
        Assert.Equal(Error.Common_KeyNotFound(notFoundKeyId).Message, ex.Message);
    }
 
    private static DateTime StringToDateTime(string input)
    {
        return DateTimeOffset.ParseExact(input, "u", CultureInfo.InvariantCulture).UtcDateTime;
    }
 
    private static KeyRingProvider CreateKeyRingProvider(ICacheableKeyRingProvider cacheableKeyRingProvider)
    {
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(m => m.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(new Mock<IAuthenticatedEncryptor>().Object);
        var options = new KeyManagementOptions();
        options.AuthenticatedEncryptorFactories.Add(mockEncryptorFactory.Object);
 
        return new KeyRingProvider(
            keyManager: null,
            keyManagementOptions: Options.Create(options),
            defaultKeyResolver: null,
            loggerFactory: NullLoggerFactory.Instance)
        {
            CacheableKeyRingProvider = cacheableKeyRingProvider
        };
    }
 
    [Fact]
    public void Unprotect_KeyNotFound_RefreshOnce_ThrowsKeyNotFound()
    {
        // Arrange
        Guid notFoundKeyId = new Guid("654057ab-2491-4471-a72a-b3b114afda38");
        byte[] protectedData = BuildProtectedDataFromCiphertext(
            keyId: notFoundKeyId,
            ciphertext: new byte[0]);
 
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(new Mock<IAuthenticatedEncryptor>().Object);
        var encryptorFactory = new AuthenticatedEncryptorFactory(NullLoggerFactory.Instance);
 
        // the keyring has only one key
        Key key = new Key(Guid.Empty, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing = new CacheableKeyRing(CancellationToken.None, DateTimeOffset.MaxValue, key, new[] { key });
 
        var keyRingProvider = CreateKeyRingProvider(new TestKeyRingProvider(keyRing));
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: keyRingProvider,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(protectedData));
        Assert.Equal(Error.Common_KeyNotFound(notFoundKeyId).Message, ex.Message);
    }
 
    [Fact]
    public void Unprotect_KeyNotFound_WontRefreshOnce_AfterTooLong()
    {
        // Arrange
        Guid notFoundKeyId = new Guid("654057ab-2491-4471-a72a-b3b114afda38");
        byte[] protectedData = BuildProtectedDataFromCiphertext(
            keyId: notFoundKeyId,
            ciphertext: new byte[0]);
 
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(new Mock<IAuthenticatedEncryptor>().Object);
        var encryptorFactory = new AuthenticatedEncryptorFactory(NullLoggerFactory.Instance);
 
        // the keyring has only one key
        Key key = new Key(Guid.Empty, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing = new CacheableKeyRing(CancellationToken.None, DateTimeOffset.MaxValue, key, new[] { key });
 
        // the refresh keyring has the notfound key
        Key key2 = new Key(notFoundKeyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing2 = new CacheableKeyRing(CancellationToken.None, DateTimeOffset.MaxValue, key, new[] { key2 });
 
        var keyRingProvider = CreateKeyRingProvider(new RefreshTestKeyRingProvider(keyRing, keyRing2));
        keyRingProvider.AutoRefreshWindowEnd = DateTime.UtcNow;
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: keyRingProvider,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(protectedData));
        Assert.Equal(Error.Common_KeyNotFound(notFoundKeyId).Message, ex.Message);
    }
 
    [Fact]
    public void Unprotect_KeyNotFound_RefreshOnce_CanFindKey()
    {
        // Arrange
        Guid notFoundKeyId = new Guid("654057ab-2491-4471-a72a-b3b114afda38");
        byte[] protectedData = BuildProtectedDataFromCiphertext(
            keyId: notFoundKeyId,
            ciphertext: new byte[0]);
 
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(new Mock<IAuthenticatedEncryptor>().Object);
        var encryptorFactory = new AuthenticatedEncryptorFactory(NullLoggerFactory.Instance);
 
        // the keyring has only one key
        Key key = new Key(Guid.Empty, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing = new CacheableKeyRing(CancellationToken.None, DateTimeOffset.MaxValue, key, new[] { key });
 
        // the refresh keyring has the notfound key
        Key key2 = new Key(notFoundKeyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing2 = new CacheableKeyRing(CancellationToken.None, DateTimeOffset.MaxValue, key, new[] { key2 });
 
        var keyRingProvider = CreateKeyRingProvider(new RefreshTestKeyRingProvider(keyRing, keyRing2));
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: keyRingProvider,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        var result = protector.Unprotect(protectedData);
        Assert.Empty(result);
    }
 
    private class TestKeyRingProvider : ICacheableKeyRingProvider
    {
        private CacheableKeyRing _keyRing;
 
        public TestKeyRingProvider(CacheableKeyRing keys) => _keyRing = keys;
 
        public CacheableKeyRing GetCacheableKeyRing(DateTimeOffset now) => _keyRing;
    }
 
    private class RefreshTestKeyRingProvider : ICacheableKeyRingProvider
    {
        private CacheableKeyRing _keyRing;
        private CacheableKeyRing _refreshKeyRing;
        private bool _called;
 
        public RefreshTestKeyRingProvider(CacheableKeyRing keys, CacheableKeyRing refreshKeys)
        {
            _keyRing = keys;
            _refreshKeyRing = refreshKeys;
        }
 
        public CacheableKeyRing GetCacheableKeyRing(DateTimeOffset now)
        {
            if (!_called)
            {
                _called = true;
                return _keyRing;
            }
            return _refreshKeyRing;
        }
    }
 
    [Fact]
    public void Unprotect_KeyRevoked_RevocationDisallowed_ThrowsKeyRevoked()
    {
        // Arrange
        Guid keyId = new Guid("654057ab-2491-4471-a72a-b3b114afda38");
        byte[] protectedData = BuildProtectedDataFromCiphertext(
            keyId: keyId,
            ciphertext: new byte[0]);
 
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(new Mock<IAuthenticatedEncryptor>().Object);
 
        // the keyring has only one key
        Key key = new Key(keyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        key.SetRevoked();
        var keyRing = new KeyRing(key, new[] { key });
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(keyRing);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert
        var ex = ExceptionAssert2.ThrowsCryptographicException(() => protector.Unprotect(protectedData));
        Assert.Equal(Error.Common_KeyRevoked(keyId).Message, ex.Message);
    }
 
    [Fact]
    public void Unprotect_KeyRevoked_RevocationAllowed_ReturnsOriginalData_SetsRevokedAndMigrationFlags()
    {
        // Arrange
        Guid defaultKeyId = new Guid("ba73c9ce-d322-4e45-af90-341307e11c38");
        byte[] expectedCiphertext = new byte[] { 0x03, 0x05, 0x07, 0x11, 0x13, 0x17, 0x19 };
        byte[] protectedData = BuildProtectedDataFromCiphertext(defaultKeyId, expectedCiphertext);
        byte[] expectedAad = BuildAadFromPurposeStrings(defaultKeyId, "purpose");
        byte[] expectedPlaintext = new byte[] { 0x23, 0x29, 0x31, 0x37 };
 
        var mockEncryptor = new Mock<IAuthenticatedEncryptor>();
        mockEncryptor
            .Setup(o => o.Decrypt(It.IsAny<ArraySegment<byte>>(), It.IsAny<ArraySegment<byte>>()))
            .Returns<ArraySegment<byte>, ArraySegment<byte>>((actualCiphertext, actualAad) =>
            {
                Assert.Equal(expectedCiphertext, actualCiphertext.AsSpan());
                Assert.Equal(expectedAad, actualAad.AsSpan());
                return expectedPlaintext;
            });
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(mockEncryptor.Object);
 
        Key defaultKey = new Key(defaultKeyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        defaultKey.SetRevoked();
        var keyRing = new KeyRing(defaultKey, new[] { defaultKey });
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(keyRing);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act
        byte[] retVal = ((IPersistedDataProtector)protector).DangerousUnprotect(protectedData,
            ignoreRevocationErrors: true,
            requiresMigration: out var requiresMigration,
            wasRevoked: out var wasRevoked);
 
        // Assert
        Assert.Equal(expectedPlaintext, retVal);
        Assert.True(requiresMigration);
        Assert.True(wasRevoked);
    }
 
    [Fact]
    public void Unprotect_IsAlsoDefaultKey_Success_NoMigrationRequired()
    {
        // Arrange
        Guid defaultKeyId = new Guid("ba73c9ce-d322-4e45-af90-341307e11c38");
        byte[] expectedCiphertext = new byte[] { 0x03, 0x05, 0x07, 0x11, 0x13, 0x17, 0x19 };
        byte[] protectedData = BuildProtectedDataFromCiphertext(defaultKeyId, expectedCiphertext);
        byte[] expectedAad = BuildAadFromPurposeStrings(defaultKeyId, "purpose");
        byte[] expectedPlaintext = new byte[] { 0x23, 0x29, 0x31, 0x37 };
 
        var mockEncryptor = new Mock<IAuthenticatedEncryptor>();
        mockEncryptor
            .Setup(o => o.Decrypt(It.IsAny<ArraySegment<byte>>(), It.IsAny<ArraySegment<byte>>()))
            .Returns<ArraySegment<byte>, ArraySegment<byte>>((actualCiphertext, actualAad) =>
            {
                Assert.Equal(expectedCiphertext, actualCiphertext.AsSpan());
                Assert.Equal(expectedAad, actualAad.AsSpan());
                return expectedPlaintext;
            });
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(mockEncryptor.Object);
 
        Key defaultKey = new Key(defaultKeyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing = new KeyRing(defaultKey, new[] { defaultKey });
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(keyRing);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert - IDataProtector
        byte[] retVal = protector.Unprotect(protectedData);
        Assert.Equal(expectedPlaintext, retVal);
 
        // Act & assert - IPersistedDataProtector
        retVal = ((IPersistedDataProtector)protector).DangerousUnprotect(protectedData,
            ignoreRevocationErrors: false,
            requiresMigration: out var requiresMigration,
            wasRevoked: out var wasRevoked);
        Assert.Equal(expectedPlaintext, retVal);
        Assert.False(requiresMigration);
        Assert.False(wasRevoked);
    }
 
    [Fact]
    public void Unprotect_IsNotDefaultKey_Success_RequiresMigration()
    {
        // Arrange
        Guid defaultKeyId = new Guid("ba73c9ce-d322-4e45-af90-341307e11c38");
        Guid embeddedKeyId = new Guid("9b5d2db3-299f-4eac-89e9-e9067a5c1853");
        byte[] expectedCiphertext = new byte[] { 0x03, 0x05, 0x07, 0x11, 0x13, 0x17, 0x19 };
        byte[] protectedData = BuildProtectedDataFromCiphertext(embeddedKeyId, expectedCiphertext);
        byte[] expectedAad = BuildAadFromPurposeStrings(embeddedKeyId, "purpose");
        byte[] expectedPlaintext = new byte[] { 0x23, 0x29, 0x31, 0x37 };
 
        var mockEncryptor = new Mock<IAuthenticatedEncryptor>();
        mockEncryptor
            .Setup(o => o.Decrypt(It.IsAny<ArraySegment<byte>>(), It.IsAny<ArraySegment<byte>>()))
            .Returns<ArraySegment<byte>, ArraySegment<byte>>((actualCiphertext, actualAad) =>
            {
                Assert.Equal(expectedCiphertext, actualCiphertext.AsSpan());
                Assert.Equal(expectedAad, actualAad.AsSpan());
                return expectedPlaintext;
            });
        var mockDescriptor = new Mock<IAuthenticatedEncryptorDescriptor>();
        var mockEncryptorFactory = new Mock<IAuthenticatedEncryptorFactory>();
        mockEncryptorFactory.Setup(o => o.CreateEncryptorInstance(It.IsAny<IKey>())).Returns(mockEncryptor.Object);
 
        Key defaultKey = new Key(defaultKeyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, new Mock<IAuthenticatedEncryptorDescriptor>().Object, new[] { mockEncryptorFactory.Object });
        Key embeddedKey = new Key(embeddedKeyId, DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, mockDescriptor.Object, new[] { mockEncryptorFactory.Object });
        var keyRing = new KeyRing(defaultKey, new[] { defaultKey, embeddedKey });
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(keyRing);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act & assert - IDataProtector
        byte[] retVal = protector.Unprotect(protectedData);
        Assert.Equal(expectedPlaintext, retVal);
 
        // Act & assert - IPersistedDataProtector
        retVal = ((IPersistedDataProtector)protector).DangerousUnprotect(protectedData,
            ignoreRevocationErrors: false,
            requiresMigration: out var requiresMigration,
            wasRevoked: out var wasRevoked);
        Assert.Equal(expectedPlaintext, retVal);
        Assert.True(requiresMigration);
        Assert.False(wasRevoked);
    }
 
    [Fact]
    public void Protect_Unprotect_RoundTripsProperly()
    {
        // Arrange
        byte[] plaintext = new byte[] { 0x10, 0x20, 0x30, 0x40, 0x50 };
        var encryptorFactory = new AuthenticatedEncryptorFactory(NullLoggerFactory.Instance);
        Key key = new Key(Guid.NewGuid(), DateTimeOffset.Now, DateTimeOffset.Now, DateTimeOffset.Now, new AuthenticatedEncryptorConfiguration().CreateNewDescriptor(), new[] { encryptorFactory });
        var keyRing = new KeyRing(key, new[] { key });
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(keyRing);
 
        var protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose");
 
        // Act - protect
        byte[] protectedData = protector.Protect(plaintext);
        Assert.NotNull(protectedData);
        Assert.NotEqual(plaintext, protectedData);
 
        // Act - unprotect
        byte[] roundTrippedPlaintext = protector.Unprotect(protectedData);
        Assert.Equal(plaintext, roundTrippedPlaintext);
    }
 
    [Fact]
    public void CreateProtector_ChainsPurposes()
    {
        // Arrange
        Guid defaultKey = new Guid("ba73c9ce-d322-4e45-af90-341307e11c38");
        byte[] expectedPlaintext = new byte[] { 0x03, 0x05, 0x07, 0x11, 0x13, 0x17, 0x19 };
        byte[] expectedAad = BuildAadFromPurposeStrings(defaultKey, "purpose1", "purpose2");
        byte[] expectedProtectedData = BuildProtectedDataFromCiphertext(defaultKey, new byte[] { 0x23, 0x29, 0x31, 0x37 });
 
        var mockEncryptor = new Mock<IAuthenticatedEncryptor>();
        mockEncryptor
            .Setup(o => o.Encrypt(It.IsAny<ArraySegment<byte>>(), It.IsAny<ArraySegment<byte>>()))
            .Returns<ArraySegment<byte>, ArraySegment<byte>>((actualPlaintext, actualAad) =>
            {
                Assert.Equal(expectedPlaintext, actualPlaintext.AsSpan());
                Assert.Equal(expectedAad, actualAad.AsSpan());
                return new byte[] { 0x23, 0x29, 0x31, 0x37 }; // ciphertext + tag
            });
 
        var mockKeyRing = new Mock<IKeyRing>(MockBehavior.Strict);
        mockKeyRing.Setup(o => o.DefaultKeyId).Returns(defaultKey);
        mockKeyRing.Setup(o => o.DefaultAuthenticatedEncryptor).Returns(mockEncryptor.Object);
        var mockKeyRingProvider = new Mock<IKeyRingProvider>();
        mockKeyRingProvider.Setup(o => o.GetCurrentKeyRing()).Returns(mockKeyRing.Object);
 
        IDataProtector protector = new KeyRingBasedDataProtector(
            keyRingProvider: mockKeyRingProvider.Object,
            logger: GetLogger(),
            originalPurposes: null,
            newPurpose: "purpose1").CreateProtector("purpose2");
 
        // Act
        byte[] retVal = protector.Protect(expectedPlaintext);
 
        // Assert
        Assert.Equal(expectedProtectedData, retVal);
    }
 
    private static byte[] BuildAadFromPurposeStrings(Guid keyId, params string[] purposes)
    {
        var expectedAad = new byte[] { 0x09, 0xF0, 0xC9, 0xF0 } // magic header
            .Concat(keyId.ToByteArray()) // key id
            .Concat(BitConverter.GetBytes(IPAddress.HostToNetworkOrder(purposes.Length))); // purposeCount
 
        foreach (string purpose in purposes)
        {
            var memStream = new MemoryStream();
            var writer = new BinaryWriter(memStream, encoding: new UTF8Encoding(encoderShouldEmitUTF8Identifier: false), leaveOpen: true);
            writer.Write(purpose); // also writes 7-bit encoded int length
            writer.Dispose();
            expectedAad = expectedAad.Concat(memStream.ToArray());
        }
 
        return expectedAad.ToArray();
    }
 
    private static byte[] BuildProtectedDataFromCiphertext(Guid keyId, byte[] ciphertext)
    {
        return new byte[] { 0x09, 0xF0, 0xC9, 0xF0 } // magic header
          .Concat(keyId.ToByteArray()) // key id
          .Concat(ciphertext).ToArray();
 
    }
 
    private static ILogger GetLogger()
    {
        var loggerFactory = NullLoggerFactory.Instance;
        return loggerFactory.CreateLogger(typeof(KeyRingBasedDataProtector));
    }
}