Skip to content
Files we used to reverse-engineer Siri
Ruby C Objective-C
Latest commit 82fcc0b Nov 14, 2011 Romain Goyet Markdown, not RedCloth
Failed to load latest commit information.
Siri.old.inline.rb Initial import Nov 14, 2011
Siri.old.rb Initial import Nov 14, 2011
Siri.rb Initial import Nov 14, 2011
Siri.txt Initial import Nov 14, 2011
sampleenc.c Initial import Nov 14, 2011
siriClient.inline.rb Initial import Nov 14, 2011
siriServer.old.rb Initial import Nov 14, 2011
siriServer.rb Initial import Nov 14, 2011
zpipe.c Initial import Nov 14, 2011

Here are the tools we wrote to reverse-engineer Siri.

The code is extremely dirty as it was written, erased, written again, and is a pure product of a trial-and-error process. Anyway, here's a simple how-to if you want to have fun with it :

How to get the necessary bits

  • Generate a certificate authority
  • Add it to your iPhone
  • Sign a certificate for "" using that authority. This should produce the ".crt" and ".key" files your server will need.
  • Setup a fake DNS server that resolves "" to your own machine, and configure your iPhone to use it.
  • Start the "siriServer.rb" server. You will need some ruby gem installed. I have tested it only on Mac OS X 10.7.2 with Ruby 1.9.2.
  • Make Siri dictation request, for example from the application. On the server, this will dump all the "interesting" bits (X-Ace-Host identifier, sessionData and such).
  • Use them to replace instances of "COMMENTED_OUT" in the code

How to do speech-to-text using a non-iPhone4S machine

  • Record your voice into whatever format you like
  • Use ffmpeg to convert the sound to raw sound samples (see the text file for the exact command line). Name it "tentative.raw"
  • Install the speex library and its header. On Mac OS X, "brew install speex" once you've setup Homebrew
  • Compile the speexEnc.m file (gcc speexEnc.m -lspeex -framework Foundation -o speexEnc)
  • Run ./speexEnc. It will produce a input.sif file with speex packets the Ruby script will be able to read
  • Run the "Siri.old.inline.rb" script. Et voilĂ  !
Something went wrong with that request. Please try again.