Move CUP to new component client_update_protocol

components/update_client/client_update_protocol_ecdsa.h

-// Copyright 2016 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_UPDATE_CLIENT_CLIENT_UPDATE_PROTOCOL_ECDSA_H_
-#define COMPONENTS_UPDATE_CLIENT_CLIENT_UPDATE_PROTOCOL_ECDSA_H_
-
-#include <stdint.h>
-
-#include <string>
-#include <vector>
-
-#include "base/memory/scoped_ptr.h"
-#include "base/strings/string_piece.h"
-
-namespace update_client {
-
-// Client Update Protocol v2, or CUP-ECDSA, is used by Google Update (Omaha)
-// servers to ensure freshness and authenticity of update checks over HTTP,
-// without the overhead of HTTPS -- namely, no PKI, no guarantee of privacy,
-// and no request replay protection (since update checks are idempotent).
-//
-// CUP-ECDSA relies on a single signing operation using ECDSA with SHA-256,
-// instead of the original CUP which used HMAC-SHA1 with a random signing key
-// encrypted using RSA.
-//
-// Each ClientUpdateProtocolEcdsa object represents a single update check in
-// flight -- a call to SignRequest() generates internal state that will be used
-// by ValidateResponse().
-class ClientUpdateProtocolEcdsa {
- public:
-  ~ClientUpdateProtocolEcdsa();
-
-  // Initializes this instance of CUP-ECDSA with a versioned public key.
-  // |key_version| must be non-negative. |public_key| is expected to be a
-  // DER-encoded ASN.1 SubjectPublicKeyInfo containing an ECDSA public key.
-  // Returns a NULL pointer on failure.
-  static scoped_ptr<ClientUpdateProtocolEcdsa> Create(
-      int key_version,
-      const base::StringPiece& public_key);
-
-  // Generates freshness/authentication data for an outgoing update check.
-  // |request_body| contains the body of the update check request in UTF-8.
-  // On return, |query_params| contains a set of query parameters (in UTF-8)
-  // to be appended to the URL.
-  //
-  // This method will store internal state in this instance used by calls to
-  // ValidateResponse(); if you need to have multiple update checks in flight,
-  // initialize a separate CUP-ECDSA instance for each one.
-  void SignRequest(const base::StringPiece& request_body,
-                   std::string* query_params);
-
-  // Validates a response given to a update check request previously signed
-  // with SignRequest(). |response_body| contains the body of the response in
-  // UTF-8. |server_proof| contains the ECDSA signature and observed request
-  // hash, which is passed in the ETag HTTP header. Returns true if the
-  // response is valid and the observed request hash matches the sent hash.
-  // This method uses internal state that is set by a prior SignRequest() call.
-  bool ValidateResponse(const base::StringPiece& response_body,
-                        const base::StringPiece& server_etag);
-
- private:
-  friend class CupEcdsaTest;
-
-  ClientUpdateProtocolEcdsa(int key_version,
-                            const base::StringPiece& public_key);
-
-  // The server keeps multiple signing keys; a version must be sent so that
-  // the correct signing key is used to sign the assembled message.
-  const int pub_key_version_;
-
-  // The ECDSA public key to use for verifying response signatures.
-  const std::vector<uint8_t> public_key_;
-
-  // The SHA-256 hash of the XML request.  This is modified on each call to
-  // SignRequest(), and checked by ValidateResponse().
-  std::vector<uint8_t> request_hash_;
-
-  // The query string containing key version and nonce in UTF-8 form.  This is
-  // modified on each call to SignRequest(), and checked by ValidateResponse().
-  std::string request_query_cup2key_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(ClientUpdateProtocolEcdsa);
-};
-
-}  // namespace update_client
-
-#endif  // COMPONENTS_UPDATE_CLIENT_CLIENT_UPDATE_PROTOCOL_ECDSA_H_