Adjusted return_to argument fetching so that unsigned parameters can be queried for when necessary.

6 files changed, 85 insertions, 70 deletions

diff --git a/src/DotNetOpenAuth.Test/OpenId/Messages/IndirectSignedResponseTests.cs b/src/DotNetOpenAuth.Test/OpenId/Messages/IndirectSignedResponseTests.cs
index 8ee43cd..e140b24 100644
--- a/src/DotNetOpenAuth.Test/OpenId/Messages/IndirectSignedResponseTests.cs
+++ b/src/DotNetOpenAuth.Test/OpenId/Messages/IndirectSignedResponseTests.cs
@@ -157,12 +157,12 @@ namespace DotNetOpenAuth.Test.OpenId.Messages {
 			Assert.IsTrue(this.response.GetReturnToParameterNames().Contains("a"));
 			Assert.AreEqual("b", this.response.GetReturnToArgument("a"));
 
-			// Now simulate them NOT being signed.
+			// Now simulate them NOT being signed.  They should still be visible at this level.
 			this.response = new IndirectSignedResponse(this.request);
 			this.response.ReturnToParametersSignatureValidated = false;
-			Assert.AreEqual(0, this.response.GetReturnToParameterNames().Count());
-			Assert.IsFalse(this.response.GetReturnToParameterNames().Contains("a"));
-			Assert.IsNull(this.response.GetReturnToArgument("a"));
+			Assert.AreEqual(1, this.response.GetReturnToParameterNames().Count());
+			Assert.IsTrue(this.response.GetReturnToParameterNames().Contains("a"));
+			Assert.AreEqual("b", this.response.GetReturnToArgument("a"));
 		}
 	}
 }
diff --git a/src/DotNetOpenAuth.Test/OpenId/RelyingParty/PositiveAuthenticationResponseTests.cs b/src/DotNetOpenAuth.Test/OpenId/RelyingParty/PositiveAuthenticationResponseTests.cs
index 48473e0..7a18c8e 100644
--- a/src/DotNetOpenAuth.Test/OpenId/RelyingParty/PositiveAuthenticationResponseTests.cs
+++ b/src/DotNetOpenAuth.Test/OpenId/RelyingParty/PositiveAuthenticationResponseTests.cs
@@ -6,6 +6,7 @@
 
 namespace DotNetOpenAuth.Test.OpenId.RelyingParty {
 	using System;
+	using System.Collections.Generic;
 	using DotNetOpenAuth.Messaging;
 	using DotNetOpenAuth.OpenId;
 	using DotNetOpenAuth.OpenId.Extensions.SimpleRegistration;
@@ -58,6 +59,29 @@ namespace DotNetOpenAuth.Test.OpenId.RelyingParty {
 			Assert.AreEqual(AuthenticationStatus.Failed, authResponse.Status);
 		}
 
+		[TestMethod]
+		public void GetCallbackArguments() {
+			PositiveAssertionResponse assertion = this.GetPositiveAssertion();
+			var rp = CreateRelyingParty();
+
+			UriBuilder returnToBuilder = new UriBuilder(assertion.ReturnTo);
+			returnToBuilder.AppendQueryArgs(new Dictionary<string, string> { { "a", "b" } });
+			assertion.ReturnTo = returnToBuilder.Uri;
+			var authResponse = new PositiveAuthenticationResponse(assertion, rp);
+
+			// First pretend that the return_to args were signed.
+			assertion.ReturnToParametersSignatureValidated = true;
+			Assert.AreEqual(1, authResponse.GetCallbackArguments().Count);
+			Assert.IsTrue(authResponse.GetCallbackArguments().ContainsKey("a"));
+			Assert.AreEqual("b", authResponse.GetCallbackArgument("a"));
+
+			// Now simulate them NOT being signed.
+			assertion.ReturnToParametersSignatureValidated = false;
+			Assert.AreEqual(0, authResponse.GetCallbackArguments().Count);
+			Assert.IsFalse(authResponse.GetCallbackArguments().ContainsKey("a"));
+			Assert.IsNull(authResponse.GetCallbackArgument("a"));
+		}
+
 		private PositiveAssertionResponse GetPositiveAssertion() {
 			Protocol protocol = Protocol.Default;
 			PositiveAssertionResponse assertion = new PositiveAssertionResponse(protocol.Version, this.returnTo);
diff --git a/src/DotNetOpenAuth.vsmdi b/src/DotNetOpenAuth.vsmdi
index 000c06d..2f5c275 100644
--- a/src/DotNetOpenAuth.vsmdi
+++ b/src/DotNetOpenAuth.vsmdi
@@ -28,7 +28,7 @@
       <TestLink id="bdba0004-be80-f5c1-1aae-487db09bdf04" name="GetReturnToArgumentDoesNotReturnExtraArgs" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="8fd673c8-977a-7b66-72cb-38c7054796c7" name="DiscoverRequireSslWithSecureRedirects" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="8a5c9404-1e77-68cf-229a-ef7ed413e6e7" name="OptionalNonNullableStruct" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="8375c7bb-b539-3396-885a-a3ca220078ec" name="InsufficientlyProtectedMessageSent" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="8346368c-9c8a-de76-18dd-5faeeac3917d" name="OPRejectsMismatchingAssociationAndSessionTypes" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="315b5857-7697-8222-f94c-f6f10d539491" name="BaseSignatureStringTest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="0290975f-02ce-d8a7-d723-5dae623cab46" name="CtorNullTokenManager" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="21cf1f9a-063f-395a-f8aa-92c190c69146" name="SignaturesMatchKnownGood" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -131,7 +131,7 @@
       <TestLink id="e2b1ae2a-8f30-b6b3-bca6-ef28fc5a0175" name="ClaimedIdAndLocalIdSpecifiedIsValid" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="577b8522-8516-4f62-22db-76227bf82f4c" name="UserSetupUrlNotRequiredInV1SetupOrV2" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="9026e58c-8582-0852-3c3c-9eadfd544cbc" name="VerifyNonZeroLengthOnEmpty" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="a59c5dc0-de4d-8136-8545-2e2e9616de46" name="SerializationWithXri" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="65f16786-7296-ee46-8a8f-82f18b211234" name="AddByKeyValuePair" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="cc0031b8-1fdb-cd87-97c1-c6f893c296e0" name="TooManyBindingElementsProvidingSameProtection" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="e2ab77b2-a6dc-f165-1485-140b9b3d916f" name="EqualityTests" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="d66a3b7a-1738-f6b3-aed1-e9bc80734ae9" name="CtorNullString" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -157,7 +157,7 @@
       <TestLink id="62c6ee5b-ac29-461c-2373-bf620e948825" name="InvalidRealmNoScheme" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="63944cb8-4c61-c42c-906f-986fa793370b" name="SignatureTest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="98e7a0f9-ab6c-7ff1-3a2c-00d8244e1bec" name="CommonMethods" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="93c157e8-1293-3aff-f616-66502872b37d" name="DiscoveryRequiresSslIgnoresInsecureEndpointsInXrds" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="385c302d-b546-c164-2a59-2e35f75d7d60" name="RemoveStructDeclaredProperty" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="e137b84a-d2a7-9af6-d15d-a92417668ccf" name="Transport" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="a1ff4ada-fe5d-d2f3-b7fb-8e72db02b3c3" name="Full" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5218fba2-d1af-e1f4-7641-9ae1d4975430" name="DirectResponsesSentUsingKeyValueForm" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -192,10 +192,9 @@
       <TestLink id="f787ae5d-b8fc-0862-a527-9157d11bbed7" name="UntrustedWebRequest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="f583b298-139a-e733-dde6-f9dc4b73d4bf" name="SendDirectMessageResponseHonorsHttpStatusCodes" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5f02e24c-2972-c598-ca71-ea362b2fe7d8" name="SecuritySettingsSetNull" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="65f16786-7296-ee46-8a8f-82f18b211234" name="AddByKeyValuePair" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="f49bcd49-76fb-bfea-b119-4e0f70159f80" name="OpenIdProvider" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5aa4dfa9-9691-bfe0-7d81-587cfa519a55" name="DirectResponsesReceivedAsKeyValueForm" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="8346368c-9c8a-de76-18dd-5faeeac3917d" name="OPRejectsMismatchingAssociationAndSessionTypes" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="832dbf28-5bf2-bd95-9029-bf798349d917" name="GetCallbackArguments" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5c66a1b8-5b20-2e3b-8427-d6ff4640ac53" name="BadRequestsGenerateValidErrorResponses" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="f6979feb-7016-4e2b-14e2-e6c2c392419f" name="RemoveByKeyValuePair" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="454165a2-c26e-5740-09a9-d234db052ba3" name="InvalidRealmNullUri" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -207,7 +206,7 @@
       <TestLink id="73c6c979-205d-2216-d98d-2dd136b352c6" name="UtcCreationDateConvertsToUniversal" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="4bd86299-18d7-abbe-e5d2-1afad17279e9" name="Parse" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="fa2e5bbd-4c41-f2b1-e875-38c6ef011fa1" name="RandomCharactersTest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="47706bc6-7bee-0385-62b4-4f9cec6cc702" name="CtorWithTextMessage" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="93c157e8-1293-3aff-f616-66502872b37d" name="DiscoveryRequiresSslIgnoresInsecureEndpointsInXrds" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="a778f331-f14e-9d6e-f942-a023423540f6" name="Ctor" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="495dd486-08dd-d365-7a84-67d96fef8460" name="SendIndirectedUndirectedMessage" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="fda58c48-e03a-73a3-4294-9a49e776ffb6" name="CtorWithTextMessageAndInnerException" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -262,6 +261,7 @@
       <TestLink id="64142858-d52e-be06-d11f-6be326c6176b" name="RespondTwoValues" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="910f8448-5454-8ae5-cba3-690c7f375576" name="ParameterNames" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="88ae5661-da27-91c5-4d78-1f43cd716127" name="EqualsTest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="8375c7bb-b539-3396-885a-a3ca220078ec" name="InsufficientlyProtectedMessageSent" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="507cd1b6-1010-0bca-cf7f-f96e3f4f6c6c" name="QueryBeforeSettingUrl" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="734dd45c-6320-26a9-e412-62ecacfd285a" name="CtorNullAttribute" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="3df1f62b-4fb4-d399-cf7f-40b72001d9d6" name="CtorUnsolicited" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -286,7 +286,6 @@
       <TestLink id="fdf439d0-3b74-4d32-d395-d5a2559ed88b" name="Ctor" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5f3758b3-1410-c742-e623-b964c01b0633" name="AuthenticationTimeUtcConvertsToUtc" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="547cfee6-bbb4-6138-a114-fc0eb6cc94f6" name="PrivateAssociationTampered" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="385c302d-b546-c164-2a59-2e35f75d7d60" name="RemoveStructDeclaredProperty" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="7650ec62-b144-f36f-8b56-31ad20521d0e" name="DoesNotStripFragment" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="14acb719-f090-018f-b870-9a5acb1d7179" name="AddAuthLevelTypes" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="90d3c411-8895-a07f-7a21-258b9d43c5b2" name="InvalidMessageNoNonceReceivedTest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -347,6 +346,7 @@
       <TestLink id="809afd59-8f10-ce37-6630-06b59351a05a" name="CommonProperties" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="ca9f3da7-e19f-b58b-54fe-54fa56ab9556" name="AddByKeyAndValue" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="95e1fc36-2500-2721-1919-35e9e8349a1c" name="AddPolicyMultipleTimes" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="a59c5dc0-de4d-8136-8545-2e2e9616de46" name="SerializationWithXri" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="aedfde98-4357-5b63-7dca-cced838ee416" name="Provider" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="ae8b7cba-696e-2362-d5e1-79a9c202a994" name="EmptyLineLoose" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="e7aacb49-62ef-637d-ada2-0a12d836414d" name="ExtensionFactory" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -355,6 +355,7 @@
       <TestLink id="fc7af2d7-6262-d761-335b-ef3ec029484d" name="DeserializeVerifyElementOrdering" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5dd2e6c9-ff0f-48de-3a1a-cbab61370843" name="SetCountNegative" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="dbf7855c-0cc6-309f-b5f5-022e0b95fe3b" name="QueryStringLookupWithoutQuery" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="736a09b4-f56e-0176-6c1c-81db0fbe3412" name="CtorUriHttpsSchemeSecure" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="cc9200bf-1399-d40a-9754-6415f0b7bcf8" name="CreateRequest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="0aa1bc22-0b26-3977-5983-5dc4a454cea5" name="OptionalNullableStruct" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="7ea157db-cf32-529f-f1d3-b3351f17725a" name="CtorSimpleServiceProvider" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -375,7 +376,6 @@
       <TestLink id="264cd371-e830-c09b-5511-18f54d4c69d5" name="RespondSimpleValue" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="035cd43a-23d5-af91-12ee-0a0ce78b3548" name="XrdsDiscoveryFromHttpHeader" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="f69f1c0c-e258-95fb-4fcb-ad14bfc40e3c" name="Discover" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="d067c55c-3715-ed87-14a2-c07349813c94" name="IsDirectedIdentity" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="ef20222d-b2e2-d593-17fa-512041020643" name="InvalidRealmNullString" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="50986611-9de6-a112-2fe8-691210989f45" name="IsTypeUriPresent" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="d647fd93-40b3-24d5-25fc-661c0d58335c" name="SendIndirectMessageFormPostNullMessage" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -389,7 +389,7 @@
       <TestLink id="9684f7bf-cdda-a2c5-0822-29cb0add3835" name="ResponseNonceGetter" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="4ba7ca33-72f1-3fc6-d37c-65134eda904d" name="AddDeclaredValueThatAlreadyExists" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5e0c892d-7ad8-6d56-1f1d-2fb6236670d6" name="CtorDefault" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
-      <TestLink id="736a09b4-f56e-0176-6c1c-81db0fbe3412" name="CtorUriHttpsSchemeSecure" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="d067c55c-3715-ed87-14a2-c07349813c94" name="IsDirectedIdentity" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="069995aa-4136-610b-3f41-df80a138c244" name="AppendQueryArgsNullUriBuilder" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="71564ca7-7845-92b3-7433-2f2beeb6b9f7" name="VerifyNonZeroLengthOnNonEmpty" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="b191e585-49d9-df8e-c156-307f798db169" name="AddAttributeRequest" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
@@ -410,6 +410,7 @@
       <TestLink id="a9f7897c-b299-807b-0612-384732cd10c9" name="Ctor" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="456c3468-9081-4879-7e7e-8299bd8c7f68" name="IsReadOnly" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="0f36556d-ece7-eb70-8597-a9d085165c2c" name="Sign" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
+      <TestLink id="47706bc6-7bee-0385-62b4-4f9cec6cc702" name="CtorWithTextMessage" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="5435ab79-de25-e2fc-0b2d-b05d5686d27d" name="IsUrlWithinRealmTests" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="06ec5bce-5a78-89c3-0cda-fa8bddfea27d" name="SetCountZero" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
       <TestLink id="93041654-1050-3878-6b90-656a7e2e3cfd" name="CtorDefault" storage="..\bin\debug\dotnetopenauth.test.dll" type="Microsoft.VisualStudio.TestTools.TestTypes.Unit.UnitTestElement, Microsoft.VisualStudio.QualityTools.Tips.UnitTest.ObjectModel,   PublicKeyToken=b03f5f7f11d50a3a" />
diff --git a/src/DotNetOpenAuth/OpenId/ChannelElements/BackwardCompatibilityBindingElement.cs b/src/DotNetOpenAuth/OpenId/ChannelElements/BackwardCompatibilityBindingElement.cs
index 071058a..4484fa4 100644
--- a/src/DotNetOpenAuth/OpenId/ChannelElements/BackwardCompatibilityBindingElement.cs
+++ b/src/DotNetOpenAuth/OpenId/ChannelElements/BackwardCompatibilityBindingElement.cs
@@ -95,15 +95,17 @@ namespace DotNetOpenAuth.OpenId.ChannelElements {
 		public MessageProtections? PrepareMessageForReceiving(IProtocolMessage message) {
 			IndirectSignedResponse response = message as IndirectSignedResponse;
 			if (response != null && response.Version.Major < 2) {
-				// Although GetReturnToArgument may return null if the parameters are not signed,
-				// the ReturnToSignatureBindingElement should have thrown an exception already
-				// if this is a 1.0 OP signed response without a valid signature since 1.0 OPs
-				// are not supposed to be able to send unsolicited assertions.
-				// Any safe solicited assertion would include our signature, allowing us to find
-				// these values.
+				// GetReturnToArgument may return parameters that are not signed,
+				// but we must allow for that since in OpenID 1.x, a stateless RP has 
+				// no way to preserve the provider endpoint and claimed identifier otherwise.  
+				// We'll verify the positive assertion later in the 
+				// RelyingParty.PositiveAuthenticationResponse constructor anyway.
+				// If this is a 1.0 OP signed response without these parameters then we didn't initiate
+				// the request ,and since 1.0 OPs are not supposed to be able to send unsolicited 
+				// assertions it's an invalid case that we throw an exception for.
 				if (response.ProviderEndpoint == null) {
 					string op_endpoint = response.GetReturnToArgument(ProviderEndpointParameterName);
-					ErrorUtilities.VerifyInternal(op_endpoint != null, ProviderEndpointParameterName + " could not be retrieved from the return_to URL.");
+					ErrorUtilities.VerifyProtocol(op_endpoint != null, MessagingStrings.RequiredParametersMissing, message.GetType().Name, ProviderEndpointParameterName);
 					response.ProviderEndpoint = new Uri(op_endpoint);
 				}
 
@@ -111,7 +113,7 @@ namespace DotNetOpenAuth.OpenId.ChannelElements {
 				if (authResponse != null) {
 					if (authResponse.ClaimedIdentifier == null) {
 						string claimedId = response.GetReturnToArgument(ClaimedIdentifierParameterName);
-						ErrorUtilities.VerifyInternal(claimedId != null, ClaimedIdentifierParameterName + " could not be retrieved from the return_to URL.");
+						ErrorUtilities.VerifyProtocol(claimedId != null, MessagingStrings.RequiredParametersMissing, message.GetType().Name, ClaimedIdentifierParameterName);
 						authResponse.ClaimedIdentifier = claimedId;
 					}
 				}
diff --git a/src/DotNetOpenAuth/OpenId/Messages/IndirectSignedResponse.cs b/src/DotNetOpenAuth/OpenId/Messages/IndirectSignedResponse.cs
index e5c4e3a..2c22171 100644
--- a/src/DotNetOpenAuth/OpenId/Messages/IndirectSignedResponse.cs
+++ b/src/DotNetOpenAuth/OpenId/Messages/IndirectSignedResponse.cs
@@ -50,11 +50,6 @@ namespace DotNetOpenAuth.OpenId.Messages {
 		private IDictionary<string, string> returnToParameters;
 
 		/// <summary>
-		/// Backing store for the <see cref="ReturnToParametersSignatureValidated"/> property.
-		/// </summary>
-		private bool returnToParametersSignatureValidated;
-
-		/// <summary>
 		/// Initializes a new instance of the <see cref="IndirectSignedResponse"/> class.
 		/// </summary>
 		/// <param name="request">
@@ -233,20 +228,7 @@ namespace DotNetOpenAuth.OpenId.Messages {
 		/// This property is not persisted in the transmitted message, and
 		/// has no effect on the Provider-side of the communication.
 		/// </remarks>
-		internal bool ReturnToParametersSignatureValidated {
-			get {
-				return this.returnToParametersSignatureValidated;
-			}
-
-			set {
-				if (this.returnToParametersSignatureValidated == value) {
-					return;
-				}
-
-				this.returnToParametersSignatureValidated = value;
-				this.returnToParameters = null;
-			}
-		}
+		internal bool ReturnToParametersSignatureValidated { get; set; }
 
 		/// <summary>
 		/// Gets or sets the nonce that will protect the message from replay attacks.
@@ -293,13 +275,7 @@ namespace DotNetOpenAuth.OpenId.Messages {
 		private IDictionary<string, string> ReturnToParameters {
 			get {
 				if (this.returnToParameters == null) {
-					// Only return data that can be validated as untampered with.
-					if (this.ReturnToParametersSignatureValidated) {
-						this.returnToParameters = HttpUtility.ParseQueryString(this.ReturnTo.Query).ToDictionary();
-					} else {
-						// Store an empty dictionary since we can't consider any callback data reliable.
-						this.returnToParameters = new Dictionary<string, string>(0);
-					}
+					this.returnToParameters = HttpUtility.ParseQueryString(this.ReturnTo.Query).ToDictionary();
 				}
 
 				return this.returnToParameters;
@@ -325,7 +301,7 @@ namespace DotNetOpenAuth.OpenId.Messages {
 		}
 
 		/// <summary>
-		/// Gets the value of a named parameter in the return_to URL.
+		/// Gets the value of a named parameter in the return_to URL without signature protection.
 		/// </summary>
 		/// <param name="key">The full name of the parameter whose value is being sought.</param>
 		/// <returns>The value of the parameter if it is present and unaltered from when
@@ -344,13 +320,10 @@ namespace DotNetOpenAuth.OpenId.Messages {
 		}
 
 		/// <summary>
-		/// Gets the names of the callback parameters added to the original authentication request.
+		/// Gets the names of the callback parameters added to the original authentication request
+		/// without signature protection.
 		/// </summary>
 		/// <returns>A sequence of the callback parameter names.</returns>
-		/// <remarks>
-		/// Callback parameters are only available if they are complete and untampered with
-		/// since the original request message (as proven by a signature).
-		/// </remarks>
 		internal IEnumerable<string> GetReturnToParameterNames() {
 			return this.ReturnToParameters.Keys;
 		}
diff --git a/src/DotNetOpenAuth/OpenId/RelyingParty/PositiveAuthenticationResponse.cs b/src/DotNetOpenAuth/OpenId/RelyingParty/PositiveAuthenticationResponse.cs
index db1720f..8d71fc6 100644
--- a/src/DotNetOpenAuth/OpenId/RelyingParty/PositiveAuthenticationResponse.cs
+++ b/src/DotNetOpenAuth/OpenId/RelyingParty/PositiveAuthenticationResponse.cs
@@ -158,13 +158,18 @@ namespace DotNetOpenAuth.OpenId.RelyingParty {
 		/// The value of the argument, or null if the named parameter could not be found.
 		/// </returns>
 		/// <remarks>
-		/// 	<para>This may return any argument on the querystring that came with the authentication response,
-		/// which may include parameters not explicitly added using
-		/// <see cref="IAuthenticationRequest.AddCallbackArguments(string, string)"/>.</para>
-		/// 	<para>Note that these values are NOT protected against tampering in transit.</para>
+		/// Callback parameters are only available if they are complete and untampered with
+		/// since the original request message (as proven by a signature).
+		/// If the relying party is operating in stateless mode <c>null</c> is always
+		/// returned since the callback arguments could not be signed to protect against
+		/// tampering.
 		/// </remarks>
 		public string GetCallbackArgument(string key) {
-			return this.response.GetReturnToArgument(key);
+			if (this.response.ReturnToParametersSignatureValidated) {
+				return this.response.GetReturnToArgument(key);
+			} else {
+				return null;
+			}
 		}
 
 		/// <summary>
@@ -174,22 +179,27 @@ namespace DotNetOpenAuth.OpenId.RelyingParty {
 		/// </summary>
 		/// <returns>A name-value dictionary.  Never null.</returns>
 		/// <remarks>
-		/// 	<para>This MAY return any argument on the querystring that came with the authentication response,
-		/// which may include parameters not explicitly added using
-		/// <see cref="IAuthenticationRequest.AddCallbackArguments(string, string)"/>.</para>
-		/// 	<para>Note that these values are NOT protected against tampering in transit.</para>
+		/// Callback parameters are only available if they are complete and untampered with
+		/// since the original request message (as proven by a signature).
+		/// If the relying party is operating in stateless mode an empty dictionary is always
+		/// returned since the callback arguments could not be signed to protect against
+		/// tampering.
 		/// </remarks>
 		public IDictionary<string, string> GetCallbackArguments() {
-			var args = new Dictionary<string, string>();
+			if (this.response.ReturnToParametersSignatureValidated) {
+				var args = new Dictionary<string, string>();
 
-			// Return all the return_to arguments, except for the OpenID-supporting ones.
-			// The only arguments that should be returned here are the ones that the host
-			// web site adds explicitly.
-			foreach (string key in this.response.GetReturnToParameterNames().Where(key => !OpenIdRelyingParty.IsOpenIdSupportingParameter(key))) {
-				args[key] = this.response.GetReturnToArgument(key);
-			}
+				// Return all the return_to arguments, except for the OpenID-supporting ones.
+				// The only arguments that should be returned here are the ones that the host
+				// web site adds explicitly.
+				foreach (string key in this.response.GetReturnToParameterNames().Where(key => !OpenIdRelyingParty.IsOpenIdSupportingParameter(key))) {
+					args[key] = this.response.GetReturnToArgument(key);
+				}
 
-			return args;
+				return args;
+			} else {
+				return EmptyDictionary<string, string>.Instance;
+			}
 		}
 
 		/// <summary>
@@ -234,6 +244,11 @@ namespace DotNetOpenAuth.OpenId.RelyingParty {
 			// Yadis.IdentifierDiscoveryCachePolicy is set to HttpRequestCacheLevel.CacheIfAvailable
 			// which means that the .NET runtime is caching our discoveries for us.  This turns out
 			// to be very fast and keeps our code clean and easily verifiable as correct and secure.
+			// CAUTION: if this discovery is ever made to be skipped based on previous discovery
+			// data that was saved to the return_to URL, be careful to verify that that information
+			// is signed by the RP before it's considered reliable.  In 1.x stateless mode, this RP
+			// doesn't (and can't) sign its own return_to URL, so its cached discovery information
+			// is merely a hint that must be verified by performing discovery again here.
 			var discoveryResults = this.response.ClaimedIdentifier.Discover(this.relyingParty.WebRequestHandler);
 			ErrorUtilities.VerifyProtocol(discoveryResults.Contains(this.endpoint), OpenIdStrings.IssuedAssertionFailsIdentifierDiscovery, this.endpoint, discoveryResults.ToStringDeferred(true));
 		}