Add TryAllDecryptionKeys flag.

Author: pmaytak

src/Microsoft.IdentityModel.JsonWebTokens/JsonWebTokenHandler.CreateToken.cs

@@ -1320,7 +1320,7 @@ internal IEnumerable<SecurityKey> GetContentEncryptionKeys(JsonWebToken jwtToken
             // 2. ResolveTokenDecryptionKey returned null
             // 3. ResolveTokenDecryptionKeyFromConfig returned null
             // Try all the keys. This is the degenerate case, not concerned about perf.
-            if (keys == null)
+            if (validationParameters.TryAllDecryptionKeys && keys.IsNullOrEmpty())
             {
                 keys = JwtTokenUtilities.GetAllDecryptionKeys(validationParameters);
                 if (configuration != null)
@@ -1335,60 +1335,62 @@ internal IEnumerable<SecurityKey> GetContentEncryptionKeys(JsonWebToken jwtToken
             // keep track of exceptions thrown, keys that were tried
             StringBuilder exceptionStrings = null;
             StringBuilder keysAttempted = null;
-            foreach (var key in keys)
+            if (keys != null)
             {
-                try
+                foreach (var key in keys)
                 {
-#if NET472 || NET6_0_OR_GREATER
-                    if (SupportedAlgorithms.EcdsaWrapAlgorithms.Contains(jwtToken.Alg))
+                    try
                     {
-                        ECDsaSecurityKey publicKey;
-
-                        // Since developers may have already worked around this issue, implicitly taking a dependency on the
-                        // old behavior, we guard the new behavior behind an AppContext switch. The new/RFC-conforming behavior
-                        // is treated as opt-in. When the library is at the point where it is able to make breaking changes
-                        // (such as the next major version update) we should consider whether or not this app-compat switch
-                        // needs to be maintained.
-                        if (AppContextSwitches.UseRfcDefinitionOfEpkAndKid)
+#if NET472 || NET6_0_OR_GREATER
+                        if (SupportedAlgorithms.EcdsaWrapAlgorithms.Contains(jwtToken.Alg))
                         {
-                            // on decryption we get the public key from the EPK value see: https://datatracker.ietf.org/doc/html/rfc7518#appendix-C
-                            jwtToken.TryGetHeaderValue(JwtHeaderParameterNames.Epk, out string epk);
-                            publicKey = new ECDsaSecurityKey(new JsonWebKey(epk), false);
+                            ECDsaSecurityKey publicKey;
+
+                            // Since developers may have already worked around this issue, implicitly taking a dependency on the
+                            // old behavior, we guard the new behavior behind an AppContext switch. The new/RFC-conforming behavior
+                            // is treated as opt-in. When the library is at the point where it is able to make breaking changes
+                            // (such as the next major version update) we should consider whether or not this app-compat switch
+                            // needs to be maintained.
+                            if (AppContextSwitches.UseRfcDefinitionOfEpkAndKid)
+                            {
+                                // on decryption we get the public key from the EPK value see: https://datatracker.ietf.org/doc/html/rfc7518#appendix-C
+                                jwtToken.TryGetHeaderValue(JwtHeaderParameterNames.Epk, out string epk);
+                                publicKey = new ECDsaSecurityKey(new JsonWebKey(epk), false);
+                            }
+                            else
+                            {
+                                publicKey = validationParameters.TokenDecryptionKey as ECDsaSecurityKey;
+                            }
+
+                            var ecdhKeyExchangeProvider = new EcdhKeyExchangeProvider(
+                                key as ECDsaSecurityKey,
+                                publicKey,
+                                jwtToken.Alg,
+                                jwtToken.Enc);
+                            jwtToken.TryGetHeaderValue(JwtHeaderParameterNames.Apu, out string apu);
+                            jwtToken.TryGetHeaderValue(JwtHeaderParameterNames.Apv, out string apv);
+                            SecurityKey kdf = ecdhKeyExchangeProvider.GenerateKdf(apu, apv);
+                            var kwp = key.CryptoProviderFactory.CreateKeyWrapProviderForUnwrap(kdf, ecdhKeyExchangeProvider.GetEncryptionAlgorithm());
+                            var unwrappedKey = kwp.UnwrapKey(Base64UrlEncoder.DecodeBytes(jwtToken.EncryptedKey));
+                            unwrappedKeys.Add(new SymmetricSecurityKey(unwrappedKey));
                         }
                         else
+#endif
+                        if (key.CryptoProviderFactory.IsSupportedAlgorithm(jwtToken.Alg, key))
                         {
-                            publicKey = validationParameters.TokenDecryptionKey as ECDsaSecurityKey;
+                            var kwp = key.CryptoProviderFactory.CreateKeyWrapProviderForUnwrap(key, jwtToken.Alg);
+                            var unwrappedKey = kwp.UnwrapKey(jwtToken.EncryptedKeyBytes);
+                            unwrappedKeys.Add(new SymmetricSecurityKey(unwrappedKey));
                         }
-
-                        var ecdhKeyExchangeProvider = new EcdhKeyExchangeProvider(
-                            key as ECDsaSecurityKey,
-                            publicKey,
-                            jwtToken.Alg,
-                            jwtToken.Enc);
-                        jwtToken.TryGetHeaderValue(JwtHeaderParameterNames.Apu, out string apu);
-                        jwtToken.TryGetHeaderValue(JwtHeaderParameterNames.Apv, out string apv);
-                        SecurityKey kdf = ecdhKeyExchangeProvider.GenerateKdf(apu, apv);
-                        var kwp = key.CryptoProviderFactory.CreateKeyWrapProviderForUnwrap(kdf, ecdhKeyExchangeProvider.GetEncryptionAlgorithm());
-                        var unwrappedKey = kwp.UnwrapKey(Base64UrlEncoder.DecodeBytes(jwtToken.EncryptedKey));
-                        unwrappedKeys.Add(new SymmetricSecurityKey(unwrappedKey));
                     }
-                    else
-#endif
-                    if (key.CryptoProviderFactory.IsSupportedAlgorithm(jwtToken.Alg, key))
+                    catch (Exception ex)
                     {
-                        var kwp = key.CryptoProviderFactory.CreateKeyWrapProviderForUnwrap(key, jwtToken.Alg);
-                        var unwrappedKey = kwp.UnwrapKey(jwtToken.EncryptedKeyBytes);
-                        unwrappedKeys.Add(new SymmetricSecurityKey(unwrappedKey));
+                        (exceptionStrings ??= new StringBuilder()).AppendLine(ex.ToString());
                     }
-                }
-                catch (Exception ex)
-                {
-                    (exceptionStrings ??= new StringBuilder()).AppendLine(ex.ToString());
-                }
 
-                (keysAttempted ??= new StringBuilder()).AppendLine(key.KeyId);
+                    (keysAttempted ??= new StringBuilder()).AppendLine(key.KeyId);
+                }
             }
-
             if (unwrappedKeys.Count > 0 || exceptionStrings is null)
                 return unwrappedKeys;
             else

src/Microsoft.IdentityModel.JsonWebTokens/JsonWebTokenHandler.DecryptToken.cs

@@ -121,7 +121,7 @@ internal ValidationResult<string> DecryptToken(
             // 2. ResolveTokenDecryptionKey returned null
             // 3. ResolveTokenDecryptionKeyFromConfig returned null
             // Try all the keys. This is the degenerate case, not concerned about perf.
-            if (keys == null)
+            if (validationParameters.TryAllDecryptionKeys && keys.IsNullOrEmpty())
             {
                 keys = validationParameters.TokenDecryptionKeys;
                 if (configuration != null)

src/Microsoft.IdentityModel.Tokens/LogMessages.cs

@@ -142,7 +142,7 @@ internal static class LogMessages
         public const string IDX10617 = "IDX10617: Encryption failed. Keywrap is only supported for: '{0}', '{1}' and '{2}'. The content encryption specified is: '{3}'.";
         public const string IDX10618 = "IDX10618: Key unwrap failed using decryption Keys: '{0}'.\nExceptions caught:\n '{1}'.\ntoken: '{2}'.";
         public const string IDX10619 = "IDX10619: Decryption failed. Algorithm: '{0}'. Either the Encryption Algorithm: '{1}' or none of the Security Keys are supported by the CryptoProviderFactory.";
-        public const string IDX10620 = "IDX10620: Unable to obtain a CryptoProviderFactory, both EncryptingCredentials.CryptoProviderFactory and EncryptingCredentials.Key.CrypoProviderFactory are null.";
+        public const string IDX10620 = "IDX10620: Unable to obtain a CryptoProviderFactory, both EncryptingCredentials.CryptoProviderFactory and EncryptingCredentials.Key.CryptoProviderFactory are null.";
         //public const string IDX10903 = "IDX10903: Token decryption succeeded. With thumbprint: '{0}'.";
         public const string IDX10904 = "IDX10904: Token decryption key : '{0}' found in TokenValidationParameters.";
         public const string IDX10905 = "IDX10905: Token decryption key : '{0}' found in Configuration/Metadata.";

src/Microsoft.IdentityModel.Tokens/PublicAPI.Unshipped.txt

@@ -1,3 +1,5 @@
 Microsoft.IdentityModel.Tokens.SecurityTokenDescriptor.IncludeKeyIdInHeader.get -> bool
 Microsoft.IdentityModel.Tokens.SecurityTokenDescriptor.IncludeKeyIdInHeader.set -> void
 static Microsoft.IdentityModel.Tokens.JsonWebKeyConverter.TryConvertToSecurityKey(Microsoft.IdentityModel.Tokens.JsonWebKey webKey, out Microsoft.IdentityModel.Tokens.SecurityKey key) -> bool
+Microsoft.IdentityModel.Tokens.TokenValidationParameters.TryAllDecryptionKeys.get -> bool
+Microsoft.IdentityModel.Tokens.TokenValidationParameters.TryAllDecryptionKeys.set -> void

src/Microsoft.IdentityModel.Tokens/TokenValidationParameters.cs

@@ -89,6 +89,7 @@ protected TokenValidationParameters(TokenValidationParameters other)
             TokenReplayCache = other.TokenReplayCache;
             TokenReplayValidator = other.TokenReplayValidator;
             TransformBeforeSignatureValidation = other.TransformBeforeSignatureValidation;
+            TryAllDecryptionKeys = other.TryAllDecryptionKeys;
             TryAllIssuerSigningKeys = other.TryAllIssuerSigningKeys;
             TypeValidator = other.TypeValidator;
             ValidateActor = other.ValidateActor;
@@ -118,6 +119,7 @@ public TokenValidationParameters()
             RequireSignedTokens = true;
             RequireAudience = true;
             SaveSigninToken = false;
+            TryAllDecryptionKeys = true;
             TryAllIssuerSigningKeys = true;
             ValidateActor = false;
             ValidateAudience = true;
@@ -552,10 +554,13 @@ public string RoleClaimType
         /// <summary>
         /// Gets or sets the <see cref="SecurityKey"/> that is to be used for decryption.
         /// </summary>
+        /// <remarks>
+        /// This <see cref="TokenDecryptionKey"/> will only be used if its <see cref="SecurityKey.KeyId"/> matches the 'kid' parameter in the token.
+        /// </remarks>
         public SecurityKey TokenDecryptionKey { get; set; }
 
         /// <summary>
-        /// Gets or sets a delegate that will be called to retreive a <see cref="SecurityKey"/> used for decryption.
+        /// Gets or sets a delegate that will be called to retrieve a <see cref="SecurityKey"/> used for decryption.
         /// </summary>
         /// <remarks>
         /// This <see cref="SecurityKey"/> will be used to decrypt the token. This can be helpful when the <see cref="SecurityToken"/> does not contain a key identifier.
@@ -565,6 +570,9 @@ public string RoleClaimType
         /// <summary>
         /// Gets or sets the <see cref="IEnumerable{SecurityKey}"/> that is to be used for decrypting inbound tokens.
         /// </summary>
+        /// <remarks>
+        /// The decryption keys in this <see cref="TokenDecryptionKeys"/> collection will only be used if their <see cref="SecurityKey.KeyId"/> matches the 'kid' parameter in the token.
+        /// </remarks>
         public IEnumerable<SecurityKey> TokenDecryptionKeys { get; set; }
 
         /// <summary>
@@ -592,7 +600,14 @@ public string RoleClaimType
         public TokenReplayValidator TokenReplayValidator { get; set; }
 
         /// <summary>
-        /// Gets or sets a value indicating whether all <see cref="IssuerSigningKeys"/> should be tried during signature validation when a key is not matched to token kid or if token kid is empty.
+        /// Gets or sets a value indicating whether all <see cref="TokenDecryptionKeys"/> should be tried during token decryption when a key is not matched to token 'kid' or if token 'kid' is empty.
+        /// The default is <c>true</c>.
+        /// </summary>
+        [DefaultValue(true)]
+        public bool TryAllDecryptionKeys { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether all <see cref="IssuerSigningKeys"/> should be tried during signature validation when a key is not matched to token 'kid' or if token 'kid' is empty.
         /// The default is <c>true</c>.
         /// </summary>
         [DefaultValue(true)]

src/Microsoft.IdentityModel.Tokens/Validation/ValidationParameters.cs

@@ -92,6 +92,7 @@ protected ValidationParameters(ValidationParameters other)
             SaveSigninToken = other.SaveSigninToken;
             _signatureValidator = other.SignatureValidator;
             TimeProvider = other.TimeProvider;
+            TryAllDecryptionKeys = other.TryAllDecryptionKeys;
             TokenDecryptionKeyResolver = other.TokenDecryptionKeyResolver;
             _tokenDecryptionKeys = other.TokenDecryptionKeys;
             TokenReplayCache = other.TokenReplayCache;
@@ -112,6 +113,7 @@ public ValidationParameters()
         {
             LogTokenId = true;
             SaveSigninToken = false;
+            TryAllDecryptionKeys = true;
             ValidateActor = false;
         }
 
@@ -478,6 +480,9 @@ public SignatureValidationDelegate? SignatureValidator
         /// <summary>
         /// Gets the <see cref="IList{T}"/> that is to be used for decrypting inbound tokens.
         /// </summary>
+        /// <remarks>
+        /// The decryption keys in this <see cref="TokenDecryptionKeys"/> collection will only be used if their <see cref="SecurityKey.KeyId"/> matches the 'kid' parameter in the token.
+        /// </remarks>
         public IList<SecurityKey> TokenDecryptionKeys
         {
             get
@@ -513,6 +518,13 @@ public TokenReplayValidationDelegate TokenReplayValidator
             set { _tokenReplayValidator = value ?? throw new ArgumentNullException(nameof(value), "TokenReplayValidator cannot be set as null."); }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether all <see cref="TokenDecryptionKeys"/> should be tried during token decryption when a key is not matched to token 'kid' or if token 'kid' is empty.
+        /// The default is <c>true</c>.
+        /// </summary>
+        [DefaultValue(true)]
+        public bool TryAllDecryptionKeys { get; set; }
+
         /// <summary>
         /// If the IssuerSigningKeyResolver is unable to resolve the key when validating the signature of the SecurityToken,
         /// all available keys will be tried.