Added version number to symmetric encryption blob.

3 files changed, 17 insertions, 4 deletions

diff --git a/src/DotNetOpenAuth/Messaging/MessagingStrings.Designer.cs b/src/DotNetOpenAuth/Messaging/MessagingStrings.Designer.cs
index f600330..235e558 100644
--- a/src/DotNetOpenAuth/Messaging/MessagingStrings.Designer.cs
+++ b/src/DotNetOpenAuth/Messaging/MessagingStrings.Designer.cs
@@ -619,6 +619,15 @@ namespace DotNetOpenAuth.Messaging {
         }
         
         /// <summary>
+        ///   Looks up a localized string similar to This blob is not a recognized encryption format..
+        /// </summary>
+        internal static string UnsupportedEncryptionAlgorithm {
+            get {
+                return ResourceManager.GetString("UnsupportedEncryptionAlgorithm", resourceCulture);
+            }
+        }
+        
+        /// <summary>
         ///   Looks up a localized string similar to The HTTP verb &apos;{0}&apos; is unrecognized and unsupported..
         /// </summary>
         internal static string UnsupportedHttpVerb {
diff --git a/src/DotNetOpenAuth/Messaging/MessagingStrings.resx b/src/DotNetOpenAuth/Messaging/MessagingStrings.resx
index 7f9d91b..fdeb756 100644
--- a/src/DotNetOpenAuth/Messaging/MessagingStrings.resx
+++ b/src/DotNetOpenAuth/Messaging/MessagingStrings.resx
@@ -315,4 +315,7 @@
   <data name="MessageTimestampInFuture" xml:space="preserve">
     <value>This message has a timestamp of {0}, which is beyond the allowable clock skew for in the future.</value>
   </data>
-</root>
+  <data name="UnsupportedEncryptionAlgorithm" xml:space="preserve">
+    <value>This blob is not a recognized encryption format.</value>
+  </data>
+</root>
\ No newline at end of file
diff --git a/src/DotNetOpenAuth/Messaging/MessagingUtilities.cs b/src/DotNetOpenAuth/Messaging/MessagingUtilities.cs
index 96b1fcf..7d0b913 100644
--- a/src/DotNetOpenAuth/Messaging/MessagingUtilities.cs
+++ b/src/DotNetOpenAuth/Messaging/MessagingUtilities.cs
@@ -513,7 +513,7 @@ namespace DotNetOpenAuth.Messaging {
 
 			var ms = new MemoryStream();
 			var binaryWriter = new BinaryWriter(ms);
-			binaryWriter.Write(crypto.IV.Length);
+			binaryWriter.Write((byte)1); // version of encryption algorithm
 			binaryWriter.Write(crypto.IV);
 			binaryWriter.Flush();
 
@@ -535,8 +535,9 @@ namespace DotNetOpenAuth.Messaging {
 
 			var ms = new MemoryStream(buffer);
 			var binaryReader = new BinaryReader(ms);
-			int ivLength = binaryReader.ReadInt32();
-			crypto.IV = binaryReader.ReadBytes(ivLength);
+			int algorithmVersion = binaryReader.ReadByte();
+			ErrorUtilities.VerifyProtocol(algorithmVersion == 1, MessagingStrings.UnsupportedEncryptionAlgorithm);
+			crypto.IV = binaryReader.ReadBytes(crypto.IV.Length);
 
 			// Allocate space for the decrypted buffer.  We don't know how long it will be yet,
 			// but it will never be larger than the encrypted buffer.