Consolidated all code and token serializations to one binding element.

6 files changed, 180 insertions, 172 deletions

diff --git a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/DotNetOpenAuth.OAuth2.AuthorizationServer.csproj b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/DotNetOpenAuth.OAuth2.AuthorizationServer.csproj
index cffffa9..9498295 100644
--- a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/DotNetOpenAuth.OAuth2.AuthorizationServer.csproj
+++ b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/DotNetOpenAuth.OAuth2.AuthorizationServer.csproj
@@ -25,7 +25,7 @@
       <DependentUpon>AuthServerStrings.resx</DependentUpon>
     </Compile>
     <Compile Include="OAuth2\AuthServerUtilities.cs" />
-    <Compile Include="OAuth2\ChannelElements\AccessRequestBindingElement.cs" />
+    <Compile Include="OAuth2\ChannelElements\TokenCodeSerializationBindingElement.cs" />
     <Compile Include="OAuth2\ChannelElements\AccessTokenBindingElement.cs" />
     <Compile Include="OAuth2\ChannelElements\AuthorizationCode.cs" />
     <Compile Include="OAuth2\ChannelElements\MessageValidationBindingElement.cs" />
diff --git a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessRequestBindingElement.cs b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessRequestBindingElement.cs
deleted file mode 100644
index 1d85630..0000000
--- a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessRequestBindingElement.cs
+++ /dev/null
@@ -1,154 +0,0 @@
-//-----------------------------------------------------------------------
-// <copyright file="AccessRequestBindingElement.cs" company="Outercurve Foundation">
-//     Copyright (c) Outercurve Foundation. All rights reserved.
-// </copyright>
-//-----------------------------------------------------------------------
-
-namespace DotNetOpenAuth.OAuth2.ChannelElements {
-	using System;
-	using System.Collections.Generic;
-	using System.Diagnostics.CodeAnalysis;
-	using System.Globalization;
-	using System.Linq;
-	using System.Security.Cryptography;
-	using System.Text;
-	using DotNetOpenAuth.Messaging;
-	using DotNetOpenAuth.Messaging.Bindings;
-	using DotNetOpenAuth.OAuth2.AuthServer.ChannelElements;
-	using DotNetOpenAuth.OAuth2.Messages;
-
-	/// <summary>
-	/// Decodes authorization codes and refresh tokens on incoming messages.
-	/// </summary>
-	/// <remarks>
-	/// This binding element also ensures that the code/token coming in is issued to
-	/// the same client that is sending the code/token and that the authorization has
-	/// not been revoked and that an access token has not expired.
-	/// </remarks>
-	internal class AccessRequestBindingElement : AuthServerBindingElementBase {
-		/// <summary>
-		/// Gets the protection commonly offered (if any) by this binding element.
-		/// </summary>
-		/// <value></value>
-		/// <remarks>
-		/// This value is used to assist in sorting binding elements in the channel stack.
-		/// </remarks>
-		public override MessageProtections Protection {
-			get { return MessageProtections.None; }
-		}
-
-		/// <summary>
-		/// Prepares a message for sending based on the rules of this channel binding element.
-		/// </summary>
-		/// <param name="message">The message to prepare for sending.</param>
-		/// <returns>
-		/// The protections (if any) that this binding element applied to the message.
-		/// Null if this binding element did not even apply to this binding element.
-		/// </returns>
-		/// <remarks>
-		/// Implementations that provide message protection must honor the
-		/// <see cref="MessagePartAttribute.RequiredProtection"/> properties where applicable.
-		/// </remarks>
-		public override MessageProtections? ProcessOutgoingMessage(IProtocolMessage message) {
-			// Serialize the authorization code, if there is one.
-			var authCodeCarrier = message as IAuthorizationCodeCarryingRequest;
-			if (authCodeCarrier != null) {
-				var codeFormatter = AuthorizationCode.CreateFormatter(this.AuthorizationServer);
-				var code = authCodeCarrier.AuthorizationDescription;
-				authCodeCarrier.Code = codeFormatter.Serialize(code);
-				return MessageProtections.None;
-			}
-
-			return null;
-		}
-
-		/// <summary>
-		/// Performs any transformation on an incoming message that may be necessary and/or
-		/// validates an incoming message based on the rules of this channel binding element.
-		/// </summary>
-		/// <param name="message">The incoming message to process.</param>
-		/// <returns>
-		/// The protections (if any) that this binding element applied to the message.
-		/// Null if this binding element did not even apply to this binding element.
-		/// </returns>
-		/// <exception cref="ProtocolException">
-		/// Thrown when the binding element rules indicate that this message is invalid and should
-		/// NOT be processed.
-		/// </exception>
-		/// <remarks>
-		/// Implementations that provide message protection must honor the
-		/// <see cref="MessagePartAttribute.RequiredProtection"/> properties where applicable.
-		/// </remarks>
-		[SuppressMessage("Microsoft.Naming", "CA2204:Literals should be spelled correctly", MessageId = "unauthorizedclient", Justification = "Protocol requirement")]
-		[SuppressMessage("Microsoft.Naming", "CA2204:Literals should be spelled correctly", MessageId = "incorrectclientcredentials", Justification = "Protocol requirement")]
-		[SuppressMessage("Microsoft.Naming", "CA2204:Literals should be spelled correctly", MessageId = "authorizationexpired", Justification = "Protocol requirement")]
-		[SuppressMessage("Microsoft.Globalization", "CA1303:Do not pass literals as localized parameters", MessageId = "DotNetOpenAuth.Messaging.ErrorUtilities.VerifyProtocol(System.Boolean,System.String,System.Object[])", Justification = "Protocol requirement")]
-		public override MessageProtections? ProcessIncomingMessage(IProtocolMessage message) {
-			var tokenRequest = message as IAuthorizationCarryingRequest;
-			if (tokenRequest != null) {
-				try {
-					var authCodeCarrier = message as IAuthorizationCodeCarryingRequest;
-					var refreshTokenCarrier = message as IRefreshTokenCarryingRequest;
-					var resourceOwnerPasswordCarrier = message as AccessTokenResourceOwnerPasswordCredentialsRequest;
-					var clientCredentialOnly = message as AccessTokenClientCredentialsRequest;
-					if (authCodeCarrier != null) {
-						var authorizationCodeFormatter = AuthorizationCode.CreateFormatter(this.AuthorizationServer);
-						var authorizationCode = authorizationCodeFormatter.Deserialize(message, authCodeCarrier.Code, Protocol.code);
-						authCodeCarrier.AuthorizationDescription = authorizationCode;
-					} else if (refreshTokenCarrier != null) {
-						var refreshTokenFormatter = RefreshToken.CreateFormatter(this.AuthorizationServer.CryptoKeyStore);
-						var refreshToken = refreshTokenFormatter.Deserialize(message, refreshTokenCarrier.RefreshToken, Protocol.refresh_token);
-						refreshTokenCarrier.AuthorizationDescription = refreshToken;
-					} else if (resourceOwnerPasswordCarrier != null) {
-						try {
-							if (this.AuthorizationServer.IsResourceOwnerCredentialValid(resourceOwnerPasswordCarrier.UserName, resourceOwnerPasswordCarrier.Password)) {
-								resourceOwnerPasswordCarrier.CredentialsValidated = true;
-							} else {
-								Logger.OAuth.ErrorFormat(
-									"Resource owner password credential for user \"{0}\" rejected by authorization server host.",
-									resourceOwnerPasswordCarrier.UserName);
-								throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.InvalidGrant, AuthServerStrings.InvalidResourceOwnerPasswordCredential);
-							}
-						} catch (NotSupportedException) {
-							throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.UnsupportedGrantType);
-						} catch (NotImplementedException) {
-							throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.UnsupportedGrantType);
-						}
-					} else if (clientCredentialOnly != null) {
-						// this method will throw later if the credentials are false.
-						clientCredentialOnly.CredentialsValidated = true;
-					} else {
-						throw ErrorUtilities.ThrowInternal("Unexpected message type: " + tokenRequest.GetType());
-					}
-				} catch (ExpiredMessageException ex) {
-					throw new TokenEndpointProtocolException(ex);
-				}
-
-				var accessRequest = tokenRequest as AccessTokenRequestBase;
-				if (accessRequest != null) {
-					// Make sure the client sending us this token is the client we issued the token to.
-					AuthServerUtilities.TokenEndpointVerify(string.Equals(accessRequest.ClientIdentifier, tokenRequest.AuthorizationDescription.ClientIdentifier, StringComparison.Ordinal), Protocol.AccessTokenRequestErrorCodes.InvalidClient);
-
-					var scopedAccessRequest = accessRequest as ScopedAccessTokenRequest;
-					if (scopedAccessRequest != null) {
-						// Make sure the scope the client is requesting does not exceed the scope in the grant.
-						if (!scopedAccessRequest.Scope.IsSubsetOf(tokenRequest.AuthorizationDescription.Scope)) {
-							Logger.OAuth.ErrorFormat("The requested access scope (\"{0}\") exceeds the grant scope (\"{1}\").", scopedAccessRequest.Scope, tokenRequest.AuthorizationDescription.Scope);
-							throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.InvalidScope, AuthServerStrings.AccessScopeExceedsGrantScope);
-						}
-					}
-				}
-
-				// Make sure the authorization this token represents hasn't already been revoked.
-				if (!this.AuthorizationServer.IsAuthorizationValid(tokenRequest.AuthorizationDescription)) {
-					Logger.OAuth.Error("Rejecting access token request because the IAuthorizationServer.IsAuthorizationValid method returned false.");
-					throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.InvalidGrant);
-				}
-
-				return MessageProtections.None;
-			}
-
-			return null;
-		}
-	}
-}
diff --git a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessTokenBindingElement.cs b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessTokenBindingElement.cs
index 1dd650c..9d7e8f2 100644
--- a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessTokenBindingElement.cs
+++ b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/AccessTokenBindingElement.cs
@@ -59,32 +59,18 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 				}
 			}
 
-			AccessToken accessToken = null;
 			if (authCarryingRequest != null) {
 				ErrorUtilities.VerifyInternal(request != null, MessagingStrings.UnexpectedMessageReceived, typeof(IAccessTokenRequestInternal), request.GetType());
-				accessToken = new AccessToken(authCarryingRequest.AuthorizationDescription, accessTokenResponse.Lifetime);
+				accessTokenResponse.AuthorizationDescription = new AccessToken(authCarryingRequest.AuthorizationDescription, accessTokenResponse.Lifetime);
 			} else if (implicitGrantResponse != null) {
 				IAccessTokenCarryingRequest tokenCarryingResponse = implicitGrantResponse;
-				accessToken = new AccessToken(
+				accessTokenResponse.AuthorizationDescription = new AccessToken(
 					request.ClientIdentifier,
 					implicitGrantResponse.Scope,
 					implicitGrantResponse.AuthorizingUsername,
 					implicitGrantResponse.Lifetime);
 			}
 
-			if (accessToken != null) {
-				accessTokenResponse.AuthorizationDescription = accessToken;
-				var accessTokenFormatter = AccessToken.CreateFormatter(this.AuthorizationServer.AccessTokenSigningKey, request.AccessTokenCreationParameters.ResourceServerEncryptionKey);
-				accessTokenResponse.AccessToken = accessTokenFormatter.Serialize(accessToken);
-			}
-
-			var refreshTokenResponse = message as AccessTokenSuccessResponse;
-			if (refreshTokenResponse != null && refreshTokenResponse.HasRefreshToken) {
-				var refreshToken = new RefreshToken(authCarryingRequest.AuthorizationDescription);
-				var refreshTokenFormatter = RefreshToken.CreateFormatter(this.AuthorizationServer.CryptoKeyStore);
-				refreshTokenResponse.RefreshToken = refreshTokenFormatter.Serialize(refreshToken);
-			}
-
 			return null;
 		}
 
diff --git a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/MessageValidationBindingElement.cs b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/MessageValidationBindingElement.cs
index 3d408ec..43ce243 100644
--- a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/MessageValidationBindingElement.cs
+++ b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/MessageValidationBindingElement.cs
@@ -17,6 +17,11 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 	/// A guard for all messages to or from an Authorization Server to ensure that they are well formed,
 	/// have valid secrets, callback URIs, etc.
 	/// </summary>
+	/// <remarks>
+	/// This binding element also ensures that the code/token coming in is issued to
+	/// the same client that is sending the code/token and that the authorization has
+	/// not been revoked and that an access token has not expired.
+	/// </remarks>
 	internal class MessageValidationBindingElement : AuthServerBindingElementBase {
 		/// <summary>
 		/// Gets the protection commonly offered (if any) by this binding element.
@@ -72,15 +77,40 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 			bool applied = false;
 
 			// Check that the client secret is correct for client authenticated messages.
+			var clientCredentialOnly = message as AccessTokenClientCredentialsRequest;
 			var authenticatedClientRequest = message as AuthenticatedClientRequestBase;
 			if (authenticatedClientRequest != null) {
 				var client = this.AuthorizationServer.GetClientOrThrow(authenticatedClientRequest.ClientIdentifier);
 				string secret = client.Secret;
 				AuthServerUtilities.TokenEndpointVerify(!string.IsNullOrEmpty(secret), Protocol.AccessTokenRequestErrorCodes.UnauthorizedClient); // an empty secret is not allowed for client authenticated calls.
 				AuthServerUtilities.TokenEndpointVerify(MessagingUtilities.EqualsConstantTime(secret, authenticatedClientRequest.ClientSecret), Protocol.AccessTokenRequestErrorCodes.InvalidClient, AuthServerStrings.ClientSecretMismatch);
+
+				if (clientCredentialOnly != null) {
+					clientCredentialOnly.CredentialsValidated = true;
+				}
+
 				applied = true;
 			}
 
+			// Check that any resource owner password credential is correct.
+			var resourceOwnerPasswordCarrier = message as AccessTokenResourceOwnerPasswordCredentialsRequest;
+			if (resourceOwnerPasswordCarrier != null) {
+				try {
+					if (this.AuthorizationServer.IsResourceOwnerCredentialValid(resourceOwnerPasswordCarrier.UserName, resourceOwnerPasswordCarrier.Password)) {
+						resourceOwnerPasswordCarrier.CredentialsValidated = true;
+					} else {
+						Logger.OAuth.ErrorFormat(
+							"Resource owner password credential for user \"{0}\" rejected by authorization server host.",
+							resourceOwnerPasswordCarrier.UserName);
+						throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.InvalidGrant, AuthServerStrings.InvalidResourceOwnerPasswordCredential);
+					}
+				} catch (NotSupportedException) {
+					throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.UnsupportedGrantType);
+				} catch (NotImplementedException) {
+					throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.UnsupportedGrantType);
+				}
+			}
+
 			// Check that authorization requests come with an acceptable callback URI.
 			var authorizationRequest = message as EndUserAuthorizationRequest;
 			if (authorizationRequest != null) {
@@ -98,6 +128,32 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 				applied = true;
 			}
 
+			var authCarrier = message as IAuthorizationCarryingRequest;
+			if (authCarrier != null) {
+				var accessRequest = authCarrier as AccessTokenRequestBase;
+				if (accessRequest != null) {
+					// Make sure the client sending us this token is the client we issued the token to.
+					AuthServerUtilities.TokenEndpointVerify(string.Equals(accessRequest.ClientIdentifier, authCarrier.AuthorizationDescription.ClientIdentifier, StringComparison.Ordinal), Protocol.AccessTokenRequestErrorCodes.InvalidClient);
+
+					var scopedAccessRequest = accessRequest as ScopedAccessTokenRequest;
+					if (scopedAccessRequest != null) {
+						// Make sure the scope the client is requesting does not exceed the scope in the grant.
+						if (!scopedAccessRequest.Scope.IsSubsetOf(authCarrier.AuthorizationDescription.Scope)) {
+							Logger.OAuth.ErrorFormat("The requested access scope (\"{0}\") exceeds the grant scope (\"{1}\").", scopedAccessRequest.Scope, authCarrier.AuthorizationDescription.Scope);
+							throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.InvalidScope, AuthServerStrings.AccessScopeExceedsGrantScope);
+						}
+					}
+				}
+
+				// Make sure the authorization this token represents hasn't already been revoked.
+				if (!this.AuthorizationServer.IsAuthorizationValid(authCarrier.AuthorizationDescription)) {
+					Logger.OAuth.Error("Rejecting access token request because the IAuthorizationServer.IsAuthorizationValid method returned false.");
+					throw new TokenEndpointProtocolException(Protocol.AccessTokenRequestErrorCodes.InvalidGrant);
+				}
+
+				applied = true;
+			}
+
 			return applied ? (MessageProtections?)MessageProtections.None : null;
 		}
 	}
diff --git a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/OAuth2AuthorizationServerChannel.cs b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/OAuth2AuthorizationServerChannel.cs
index 9c15045..09d35ee 100644
--- a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/OAuth2AuthorizationServerChannel.cs
+++ b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/OAuth2AuthorizationServerChannel.cs
@@ -116,7 +116,7 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 			// The order they are provided is used for outgoing messgaes, and reversed for incoming messages.
 			bindingElements.Add(new MessageValidationBindingElement());
 			bindingElements.Add(new AccessTokenBindingElement());
-			bindingElements.Add(new AccessRequestBindingElement());
+			bindingElements.Add(new TokenCodeSerializationBindingElement());
 
 			return bindingElements.ToArray();
 		}
diff --git a/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/TokenCodeSerializationBindingElement.cs b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/TokenCodeSerializationBindingElement.cs
new file mode 100644
index 0000000..b14f366
--- /dev/null
+++ b/src/DotNetOpenAuth.OAuth2.AuthorizationServer/OAuth2/ChannelElements/TokenCodeSerializationBindingElement.cs
@@ -0,0 +1,120 @@
+//-----------------------------------------------------------------------
+// <copyright file="TokenCodeSerializationBindingElement.cs" company="Outercurve Foundation">
+//     Copyright (c) Outercurve Foundation. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.OAuth2.ChannelElements {
+	using System;
+	using System.Collections.Generic;
+	using System.Diagnostics.CodeAnalysis;
+	using System.Globalization;
+	using System.Linq;
+	using System.Security.Cryptography;
+	using System.Text;
+	using DotNetOpenAuth.Messaging;
+	using DotNetOpenAuth.Messaging.Bindings;
+	using DotNetOpenAuth.OAuth2.AuthServer.ChannelElements;
+	using DotNetOpenAuth.OAuth2.Messages;
+
+	/// <summary>
+	/// Serializes and deserializes authorization codes, refresh tokens and access tokens
+	/// on incoming and outgoing messages.
+	/// </summary>
+	internal class TokenCodeSerializationBindingElement : AuthServerBindingElementBase {
+		/// <summary>
+		/// Gets the protection commonly offered (if any) by this binding element.
+		/// </summary>
+		/// <value></value>
+		/// <remarks>
+		/// This value is used to assist in sorting binding elements in the channel stack.
+		/// </remarks>
+		public override MessageProtections Protection {
+			get { return MessageProtections.None; }
+		}
+
+		/// <summary>
+		/// Prepares a message for sending based on the rules of this channel binding element.
+		/// </summary>
+		/// <param name="message">The message to prepare for sending.</param>
+		/// <returns>
+		/// The protections (if any) that this binding element applied to the message.
+		/// Null if this binding element did not even apply to this binding element.
+		/// </returns>
+		/// <remarks>
+		/// Implementations that provide message protection must honor the
+		/// <see cref="MessagePartAttribute.RequiredProtection"/> properties where applicable.
+		/// </remarks>
+		public override MessageProtections? ProcessOutgoingMessage(IProtocolMessage message) {
+			var directResponse = message as IDirectResponseProtocolMessage;
+			var request = directResponse != null ? directResponse.OriginatingRequest as IAccessTokenRequestInternal : null;
+
+			// Serialize the authorization code, if there is one.
+			var authCodeCarrier = message as IAuthorizationCodeCarryingRequest;
+			if (authCodeCarrier != null) {
+				var codeFormatter = AuthorizationCode.CreateFormatter(this.AuthorizationServer);
+				var code = authCodeCarrier.AuthorizationDescription;
+				authCodeCarrier.Code = codeFormatter.Serialize(code);
+				return MessageProtections.None;
+			}
+
+			// Serialize the refresh token, if applicable.
+			var refreshTokenResponse = message as AccessTokenSuccessResponse;
+			if (refreshTokenResponse != null && refreshTokenResponse.HasRefreshToken) {
+				var refreshTokenCarrier = (IAuthorizationCarryingRequest)message;
+				var refreshToken = new RefreshToken(refreshTokenCarrier.AuthorizationDescription);
+				var refreshTokenFormatter = RefreshToken.CreateFormatter(this.AuthorizationServer.CryptoKeyStore);
+				refreshTokenResponse.RefreshToken = refreshTokenFormatter.Serialize(refreshToken);
+			}
+
+			// Serialize the access token, if applicable.
+			var accessTokenResponse = message as IAccessTokenIssuingResponse;
+			if (accessTokenResponse != null && accessTokenResponse.AuthorizationDescription != null) {
+				ErrorUtilities.VerifyInternal(request != null, "We should always have a direct request message for this case.");
+				var accessTokenFormatter = AccessToken.CreateFormatter(this.AuthorizationServer.AccessTokenSigningKey, request.AccessTokenCreationParameters.ResourceServerEncryptionKey);
+				accessTokenResponse.AccessToken = accessTokenFormatter.Serialize(accessTokenResponse.AuthorizationDescription);
+			}
+
+			return null;
+		}
+
+		/// <summary>
+		/// Performs any transformation on an incoming message that may be necessary and/or
+		/// validates an incoming message based on the rules of this channel binding element.
+		/// </summary>
+		/// <param name="message">The incoming message to process.</param>
+		/// <returns>
+		/// The protections (if any) that this binding element applied to the message.
+		/// Null if this binding element did not even apply to this binding element.
+		/// </returns>
+		/// <exception cref="ProtocolException">
+		/// Thrown when the binding element rules indicate that this message is invalid and should
+		/// NOT be processed.
+		/// </exception>
+		/// <remarks>
+		/// Implementations that provide message protection must honor the
+		/// <see cref="MessagePartAttribute.RequiredProtection"/> properties where applicable.
+		/// </remarks>
+		[SuppressMessage("Microsoft.Naming", "CA2204:Literals should be spelled correctly", MessageId = "unauthorizedclient", Justification = "Protocol requirement")]
+		[SuppressMessage("Microsoft.Naming", "CA2204:Literals should be spelled correctly", MessageId = "incorrectclientcredentials", Justification = "Protocol requirement")]
+		[SuppressMessage("Microsoft.Naming", "CA2204:Literals should be spelled correctly", MessageId = "authorizationexpired", Justification = "Protocol requirement")]
+		[SuppressMessage("Microsoft.Globalization", "CA1303:Do not pass literals as localized parameters", MessageId = "DotNetOpenAuth.Messaging.ErrorUtilities.VerifyProtocol(System.Boolean,System.String,System.Object[])", Justification = "Protocol requirement")]
+		public override MessageProtections? ProcessIncomingMessage(IProtocolMessage message) {
+			var authCodeCarrier = message as IAuthorizationCodeCarryingRequest;
+			if (authCodeCarrier != null) {
+				var authorizationCodeFormatter = AuthorizationCode.CreateFormatter(this.AuthorizationServer);
+				var authorizationCode = authorizationCodeFormatter.Deserialize(message, authCodeCarrier.Code, Protocol.code);
+				authCodeCarrier.AuthorizationDescription = authorizationCode;
+			}
+
+			var refreshTokenCarrier = message as IRefreshTokenCarryingRequest;
+			if (refreshTokenCarrier != null) {
+				var refreshTokenFormatter = RefreshToken.CreateFormatter(this.AuthorizationServer.CryptoKeyStore);
+				var refreshToken = refreshTokenFormatter.Deserialize(message, refreshTokenCarrier.RefreshToken, Protocol.refresh_token);
+				refreshTokenCarrier.AuthorizationDescription = refreshToken;
+			}
+
+			return null;
+		}
+	}
+}