content/public/browser/media_device_id.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 #include "content/public/browser/media_device_id.h"
   5
   6 #include "base/logging.h"
   7 #include "base/strings/string_number_conversions.h"
   8 #include "base/strings/string_util.h"
   9 #include "crypto/hmac.h"
  10
  11 namespace content {
  12
  13 std::string GetHMACForMediaDeviceID(const GURL& security_origin,
  14                                     const std::string& raw_unique_id) {
  15   DCHECK(security_origin.is_valid());
  16   DCHECK(!raw_unique_id.empty());
  17   crypto::HMAC hmac(crypto::HMAC::SHA256);
  18   const size_t digest_length = hmac.DigestLength();
  19   std::vector<uint8> digest(digest_length);
  20   bool result = hmac.Init(security_origin.spec()) &&
  21       hmac.Sign(raw_unique_id, &digest[0], digest.size());
  22   DCHECK(result);
  23   return StringToLowerASCII(base::HexEncode(&digest[0], digest.size()));
  24 }
  25
  26 bool DoesMediaDeviceIDMatchHMAC(const GURL& security_origin,
  27                                 const std::string& device_guid,
  28                                 const std::string& raw_unique_id) {
  29   DCHECK(security_origin.is_valid());
  30   DCHECK(!raw_unique_id.empty());
  31   std::string guid_from_raw_device_id =
  32       GetHMACForMediaDeviceID(security_origin, raw_unique_id);
  33   return guid_from_raw_device_id == device_guid;
  34 }
  35
  36 }  // namespace content