Cast: Adding helper crypto classes

media/cast/cast_defines.h

 // Copyright 2013 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 MEDIA_CAST_CAST_DEFINES_H_
 #define MEDIA_CAST_CAST_DEFINES_H_
 
 #include <map>
 #include <set>
 
@@ skipping 37 matching lines @@
   kTooOldPacket,
 };
 
 const uint16 kRtcpCastAllPacketsLost = 0xffff;
 
 const size_t kMinLengthOfRtcp = 8;
 
 // Basic RTP header + cast header.
 const size_t kMinLengthOfRtp = 12 + 6;
 
-const size_t kAesBlockSize = 16;
-const size_t kAesKeySize = 16;
-
 // Each uint16 represents one packet id within a cast frame.
 typedef std::set<uint16> PacketIdSet;
 // Each uint8 represents one cast frame.
 typedef std::map<uint8, PacketIdSet> MissingFramesAndPacketsMap;
 
 // TODO(pwestin): Re-factor the functions bellow into a class with static
 // methods.
 
 // January 1970, in NTP seconds.
 // Network Time Protocol (NTP), which is in seconds relative to 0h UTC on
@@ skipping 69 matching lines @@
   int64 ntp_time_us = static_cast<int64>(ntp_seconds) *
       base::Time::kMicrosecondsPerSecond +
           static_cast<int64>(ntp_fractions) / kMagicFractionalUnit;
 
   base::TimeDelta elapsed_since_unix_epoch =
       base::TimeDelta::FromMicroseconds(ntp_time_us -
           (kUnixEpochInNtpSeconds * base::Time::kMicrosecondsPerSecond));
   return base::TimeTicks::UnixEpoch() + elapsed_since_unix_epoch;
 }
 
-inline std::string GetAesNonce(uint32 frame_id, const std::string& iv_mask) {
-  std::string aes_nonce(kAesBlockSize, 0);
-
-  // Serializing frame_id in big-endian order (aes_nonce[8] is the most
-  // significant byte of frame_id).
-  aes_nonce[11] = frame_id & 0xff;
-  aes_nonce[10] = (frame_id >> 8) & 0xff;
-  aes_nonce[9] = (frame_id >> 16) & 0xff;
-  aes_nonce[8] = (frame_id >> 24) & 0xff;
-
-  for (size_t i = 0; i < kAesBlockSize; ++i) {
-    aes_nonce[i] ^= iv_mask[i];
-  }
-  return aes_nonce;
-}
-
 inline uint32 GetVideoRtpTimestamp(const base::TimeTicks& time_ticks) {
   base::TimeTicks zero_time;
   base::TimeDelta recorded_delta = time_ticks - zero_time;
   // Timestamp is in 90 KHz for video.
   return static_cast<uint32>(recorded_delta.InMilliseconds() * 90);
 }
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_CAST_DEFINES_H_