Updating D2D protocol to v1 to support separate sequence numbers.

components/cryptauth/device_to_device_secure_context.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_CRYPTAUTH_DEVICE_TO_DEVICE_SECURE_CONTEXT_H_
 #define COMPONENTS_CRYPTAUTH_DEVICE_TO_DEVICE_SECURE_CONTEXT_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "components/cryptauth/secure_context.h"
 
 namespace securemessage {
 class Header;
 }
 
 namespace cryptauth {
 
 class SecureMessageDelegate;
+class SessionKeys;
 
 // SecureContext implementation for the DeviceToDevice protocol.
 class DeviceToDeviceSecureContext : public SecureContext {
  public:
   DeviceToDeviceSecureContext(
       std::unique_ptr<SecureMessageDelegate> secure_message_delegate,
-      const std::string& symmetric_key,
+      std::unique_ptr<SessionKeys> session_keys,
       const std::string& responder_auth_message_,
       ProtocolVersion protocol_version);
 
   ~DeviceToDeviceSecureContext() override;
 
   // SecureContext:
   void Decode(const std::string& encoded_message,
               const MessageCallback& callback) override;
   void Encode(const std::string& message,
               const MessageCallback& callback) override;
   ProtocolVersion GetProtocolVersion() const override;
   std::string GetChannelBindingData() const override;
 
  private:
   // Callback for unwrapping a secure message. |callback| will be invoked with
   // the decrypted payload if the message is unwrapped successfully; otherwise
   // it will be invoked with an empty string.
   void HandleUnwrapResult(
       const DeviceToDeviceSecureContext::MessageCallback& callback,
       bool verified,
       const std::string& payload,
       const securemessage::Header& header);
 
   // Delegate for handling the creation and unwrapping of SecureMessages.
   std::unique_ptr<SecureMessageDelegate> secure_message_delegate_;
 
-  // The symmetric key used to create and unwrap messages.
-  const std::string symmetric_key_;
+  // The symmetric keys used to create and unwrap messages.
+  std::unique_ptr<SessionKeys> session_keys_;
 
   // The [Responder Auth] message received from the remote device during
   // authentication.
   const std::string responder_auth_message_;
 
   // The protocol version supported by the remote device.
   const ProtocolVersion protocol_version_;
 
-  // The last sequence number of the message sent or received.
-  int last_sequence_number_;
+  // The last sequence number of the message sent.
+  int last_encode_sequence_number_;
+
+  // The last sequence number of the message received.
+  int last_decode_sequence_number_;
 
   base::WeakPtrFactory<DeviceToDeviceSecureContext> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceToDeviceSecureContext);
 };
 
 }  // namespace cryptauth
 
 #endif  // COMPONENTS_CRYPTAUTH_DEVICE_TO_DEVICE_SECURE_CONTEXT_H_