Auth work to support new auth protocol

chrome/browser/extensions/api/cast_channel/cast_channel.proto

Index: chrome/browser/extensions/api/cast_channel/cast_channel.proto
diff --git a/chrome/browser/extensions/api/cast_channel/cast_channel.proto b/chrome/browser/extensions/api/cast_channel/cast_channel.proto
index d321eaf8ad6c3a69b90fd5bbd436dcefe254e6ad..fd226541d5abdf22730b462ec9de946aa9b021d4 100644
--- a/chrome/browser/extensions/api/cast_channel/cast_channel.proto
+++ b/chrome/browser/extensions/api/cast_channel/cast_channel.proto
@@ -53,19 +53,31 @@ message CastMessage {
   optional bytes payload_binary = 7;
 }
 
+enum SignatureAlgorithm {
+  UNSPECIFIED = 0;
+  RSASSA_PKCS1v15 = 1;
+  RSASSA_PSS = 2;

[Ryan Sleevi, 2014/04/30 01:32:13]

Just to confirm, you can change this symbolic name later, right?

In the case of PSS, you'd also want to specify the parameters (the salt/mgf
function - although collectively, just use mgf1 with SHA-whatever)

Concretely:
RSASSA_PKCS1v15 -> RSASSA_PKCS1v15_SHA1
RSASSA_PSS -> RSASSA_PSS_SHA256

[Munjal (Google), 2014/05/05 00:01:46]

This is just a copy of the proto definition that is in the spec and is also on
the server side. Yes, we can change the name in the future without problems.

[mark a. foltz, 2014/05/05 19:22:22]

Only the value is sent on the wire so names can be changed later (obviously you
don't want to change the meaning by doing so).

+}
+
 // Messages for authentication protocol between a sender and a receiver.
 message AuthChallenge {
+  optional SignatureAlgorithm signature_algorithm = 1
+      [default = RSASSA_PKCS1v15];
 }
 
 message AuthResponse {
   required bytes signature = 1;
   required bytes client_auth_certificate = 2;
+  repeated bytes intermediate_certificate = 3;
+  optional SignatureAlgorithm signature_algorithm = 4
+      [default = RSASSA_PKCS1v15];
 }
 
 message AuthError {
   enum ErrorType {
     INTERNAL_ERROR = 0;
     NO_TLS = 1;  // The underlying connection is not TLS
+    SIGNATURE_ALGORITHM_UNAVAILABLE = 2;
   }
   required ErrorType error_type = 1;
 }