1 files changed, 100 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.OAuth2/OAuth2/ChannelElements/AuthorizationCode.cs b/src/DotNetOpenAuth.OAuth2/OAuth2/ChannelElements/AuthorizationCode.cs
new file mode 100644
index 0000000..6900b89
--- /dev/null
+++ b/src/DotNetOpenAuth.OAuth2/OAuth2/ChannelElements/AuthorizationCode.cs
@@ -0,0 +1,100 @@
+//-----------------------------------------------------------------------
+// <copyright file="AuthorizationCode.cs" company="Andrew Arnott">
+//     Copyright (c) Andrew Arnott. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.OAuth2.ChannelElements {
+	using System;
+	using System.Collections.Generic;
+	using System.Diagnostics.Contracts;
+	using System.Security.Cryptography;
+	using System.Text;
+	using DotNetOpenAuth.Messaging;
+
+	/// <summary>
+	/// Represents the authorization code created when a user approves authorization that
+	/// allows the client to request an access/refresh token.
+	/// </summary>
+	internal class AuthorizationCode : AuthorizationDataBag {
+		/// <summary>
+		/// The name of the bucket for symmetric keys used to sign authorization codes.
+		/// </summary>
+		internal const string AuthorizationCodeKeyBucket = "https://localhost/dnoa/oauth_authorization_code";
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="AuthorizationCode"/> class.
+		/// </summary>
+		public AuthorizationCode() {
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="AuthorizationCode"/> class.
+		/// </summary>
+		/// <param name="clientIdentifier">The client identifier.</param>
+		/// <param name="callback">The callback the client used to obtain authorization.</param>
+		/// <param name="scopes">The authorized scopes.</param>
+		/// <param name="username">The name on the account that authorized access.</param>
+		internal AuthorizationCode(string clientIdentifier, Uri callback, IEnumerable<string> scopes, string username) {
+			Requires.NotNullOrEmpty(clientIdentifier, "clientIdentifier");
+			Requires.NotNull(callback, "callback");
+
+			this.ClientIdentifier = clientIdentifier;
+			this.CallbackHash = CalculateCallbackHash(callback);
+			this.Scope.ResetContents(scopes);
+			this.User = username;
+			this.UtcCreationDate = DateTime.UtcNow;
+		}
+
+		/// <summary>
+		/// Gets or sets the hash of the callback URL.
+		/// </summary>
+		[MessagePart("cb")]
+		private byte[] CallbackHash { get; set; }
+
+		/// <summary>
+		/// Creates a serializer/deserializer for this type.
+		/// </summary>
+		/// <param name="authorizationServer">The authorization server that will be serializing/deserializing this authorization code.  Must not be null.</param>
+		/// <returns>A DataBag formatter.</returns>
+		internal static IDataBagFormatter<AuthorizationCode> CreateFormatter(IAuthorizationServer authorizationServer) {
+			Requires.NotNull(authorizationServer, "authorizationServer");
+			Contract.Ensures(Contract.Result<IDataBagFormatter<AuthorizationCode>>() != null);
+
+			return new UriStyleMessageFormatter<AuthorizationCode>(
+				authorizationServer.CryptoKeyStore,
+				AuthorizationCodeKeyBucket,
+				signed: true,
+				encrypted: true,
+				compressed: false,
+				maximumAge: AuthorizationCodeBindingElement.MaximumMessageAge,
+				decodeOnceOnly: authorizationServer.VerificationCodeNonceStore);
+		}
+
+		/// <summary>
+		/// Verifies the the given callback URL matches the callback originally given in the authorization request.
+		/// </summary>
+		/// <param name="callback">The callback.</param>
+		/// <remarks>
+		/// This method serves to verify that the callback URL given in the original authorization request
+		/// and the callback URL given in the access token request match.
+		/// </remarks>
+		/// <exception cref="ProtocolException">Thrown when the callback URLs do not match.</exception>
+		internal void VerifyCallback(Uri callback) {
+			ErrorUtilities.VerifyProtocol(MessagingUtilities.AreEquivalent(this.CallbackHash, CalculateCallbackHash(callback)), Protocol.redirect_uri_mismatch);
+		}
+
+		/// <summary>
+		/// Calculates the hash of the callback URL.
+		/// </summary>
+		/// <param name="callback">The callback whose hash should be calculated.</param>
+		/// <returns>
+		/// A base64 encoding of the hash of the URL.
+		/// </returns>
+		private static byte[] CalculateCallbackHash(Uri callback) {
+			using (var hasher = new SHA256Managed()) {
+				return hasher.ComputeHash(Encoding.UTF8.GetBytes(callback.AbsoluteUri));
+			}
+		}
+	}
+}