Cast: Reshuffle files under media/cast

media/cast/common/transport_encryption_handler.cc

Index: media/cast/common/transport_encryption_handler.cc
diff --git a/media/cast/transport/utility/transport_encryption_handler.cc b/media/cast/common/transport_encryption_handler.cc
similarity index 76%
rename from media/cast/transport/utility/transport_encryption_handler.cc
rename to media/cast/common/transport_encryption_handler.cc
index 49a6cd3ede0a737c7419c51db6656d622b25d681..00980dfcddaf293db067b6d6cf30fe459b4128c9 100644
--- a/media/cast/transport/utility/transport_encryption_handler.cc
+++ b/media/cast/common/transport_encryption_handler.cc
@@ -2,16 +2,39 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "media/cast/transport/utility/transport_encryption_handler.h"
+#include "media/cast/common/transport_encryption_handler.h"
 
 #include "base/logging.h"
 #include "crypto/encryptor.h"
 #include "crypto/symmetric_key.h"
 #include "media/cast/transport/cast_transport_defines.h"
 
+namespace {
+
+// Crypto.
+const size_t kAesBlockSize = 16;
+const size_t kAesKeySize = 16;
+
+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;
+}
+
+}  // namespace
+
 namespace media {
 namespace cast {
-namespace transport {
 
 TransportEncryptionHandler::TransportEncryptionHandler()
     : key_(), encryptor_(), iv_mask_(), is_activated_(false) {}
@@ -60,7 +83,7 @@ bool TransportEncryptionHandler::Decrypt(uint32 frame_id,
   if (!is_activated_) {
     return false;
   }
-  if (!encryptor_->SetCounter(transport::GetAesNonce(frame_id, iv_mask_))) {
+  if (!encryptor_->SetCounter(GetAesNonce(frame_id, iv_mask_))) {
     NOTREACHED() << "Failed to set counter";
     return false;
   }
@@ -71,6 +94,5 @@ bool TransportEncryptionHandler::Decrypt(uint32 frame_id,
   return true;
 }
 
-}  // namespace transport
 }  // namespace cast
 }  // namespace media