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• Non-RSA TLS1.2 Packet decryption

  7 février 2017, par Joseph Wahba

  I am trying to decrypt a pcap file. This pcap file contains a capture of an HLS encrypted video stream. The pcap contains TLSv1.2 packets.

  Below are some information from the pcap file

  Server Hello message Cipher Suite :

  TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384.

  EC Diffie-Hellman server Params : pubkey (1)

  The Certificate Status message :

  Signature Hash Algorithm Hash : SHA256

  Signature Hash Algorithm Signature : ECDSA

  Client Key Exchange Message

  EC Diffie-Hellman server Params : pubkey (2)

  I tried to follow this Wireshark SSL decryption tutorial. But it seems that it works only for RSA encryptions.
  I have been researching for a while and found this discussion. I am quoting an extract from this discussion :

  There is an important parameter to mind : decryption of a passively
  recorded session (with a copy of the server private key) works only if
  the key exchange was of type RSA or static DH ; with "DHE" and "ECDHE"
  cipher suites, you won’t be able to decrypt such a session, even with
  knowledge of the server private key. In that case, you will need
  either the negotiated "master secret", or to use the server private
  key to actively intercept the connection

  It’s note worthy that I have the client private key. In my case, the client is FFmpeg video streamer (FFplay). I had a look also on the TLS v1.2 RFC.

  My question :

  Is it possible to do a decryption in this scenario ? If yes, what do I need to have to do so ?

  Is the decryption done using the client’s private key or using the pre_shared_master (i.e. Diffie-Hellman) ?

• avformat : add vapoursynth wrapper

  27 avril 2018, par wm4

  avformat : add vapoursynth wrapper
  This can "demux" .vpy files. Autodetection of .vpy scripts is
  
  intentionally not done, because it would be a major security issue. You
  
  need to force the format, for example with "-f vapoursynth" for the
  
  FFmpeg CLI tools.
  Some minor code copied from other LGPL parts of FFmpeg.
  I did not find a good way to test a few of the more obscure VS features,
  
  like VFR nodes, compat pixel formats, or nodes with dynamic size/format
  
  changes. These can be easily implemented on demand.
  

  • [DH] configure
  • [DH] libavformat/Makefile
  • [DH] libavformat/allformats.c
  • [DH] libavformat/vapoursynth.c
  • [DH] libavformat/version.h

• Converting DAV to MP4 and OGG

  25 avril, par mackowiakp

  I want to prepare WEB page containing films from security camera recorders. Each recorder transmit video files in DAV format so each film is converted to MP4 format by script, using such syntax :

  



  ffmpeg -y -i movie.dav -vcodec libx264 -crf 24 movie.mp4


  



  So I included in HTMLv5 code such entry :

  



   <video width="320" height="240">&#xA;  <source src="movie.mp4" type="video/mp4">&#xA;</source></video> &#xA;

  



  It works correctly with Chrome but not with Firefox. For proper work in FF it is necessary add link to OGG file. So correct HTMLv5 syntax for both browsers should look like this :

  



   <video width="320" height="240">&#xA;  <source src="movie.mp4" type="video/mp4">&#xA;  <source src="movie.ogg" type="video/ogg">&#xA;</source></source></video>&#xA;

  



  Can anybody help me to pass correct ffmpeg syntax to create OGG file ?

  



  Output from console after using -movflags +faststart options

  



  [maciek@piotr MMM]$ ../ffmpeg-2.4.2-64bit-static/ffmpeg -movflags +faststart -y -i   04.24.23-04.24.38\[M\]\[@0\]\[0\].dav -vcodec libx264 -crf 24 10.mp4
ffmpeg version 2.4.2-   http://johnvansickle.com/ffmpeg/    Copyright (c) 2000-2014 the FFmpeg developers
  built on Oct  9 2014 07:24:56 with gcc 4.8 (Debian 4.8.3-11)
  configuration: --enable-gpl --enable-version3 --disable-shared --disable-debug --enable-runtime-cpudetect --enable-libmp3lame --enable-libx264 --enable-libx265 --enable- libwebp --enable-libspeex --enable-libvorbis --enable-libvpx --enable-libfreetype --enable-fontconfig --enable-libxvid --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-gray --enable-libopenjpeg --enable-libopus --disable-ffserver --enable-libass --enable-gnutls --cc=gcc-4.8
  libavutil      54.  7.100 / 54.  7.100
  libavcodec     56.  1.100 / 56.  1.100
  libavformat    56.  4.101 / 56.  4.101
  libavdevice    56.  0.100 / 56.  0.100
  libavfilter     5.  1.100 /  5.  1.100
  libswscale      3.  0.100 /  3.  0.100
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  0.100 / 53.  0.100
Option movflags not found.