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This page assembles various matters related to the International Journal of Proof-of-Concept or Get The Fuck Out (PoC||GTFO or PoC or GTFO)
I limit voluntarily myself to topics I've been directly involved with.


  • PoC||GTFO 0x05 3: ECB as an Electronic Coloring Book
  • PoC||GTFO 0x06 7: More Cryptographic Coloring Books (original title was "Coloring Book Continued")
    • Errata in 7.6 due to Frenglish to English translation ;-) : OFB and CTR are fine, only CBC & CFB can be compared to ECB
  • PoC||GTFO 0x08 12: Weird cryptography; or, How to resist brute-force attacks.
    • See also Sci-Fi Crypto
    • pocorgtfo08.pdf itself is also a ZIP and a shell script to perform grammatically correct encryption
  • PoC||GTFO 0x09 12: What If You Could Listen to This PDF?
    • pocorgtfo09.pdf itself is also a ZIP and a WavPack audio file
  • PoC||GTFO 0x12 11: Are Androids Polyglots?
    • pocorgtfo12.pdf itself is also a ZIP and an Android APK able to share itself via NFC
  • PoC||GTFO 0x13 10: Post Scriptum: A Schizophrenic Ghost, with E. Sultanik
    • pocorgtfo12.pdf itself is also a ZIP and a PostScript file

Misc from PoC||GTFO

PoC||GTFO 0x06

Happy thanksgiving ;)

sed '4025,4048!d' pocorgtfo06.pdf
Spoilers for our Pictures of Cats

- 1.png is a PNG picture. It's a RGB picture, with a palette.
  The RGB values have been altered to display another picture via the palette.
  So just change offset 0x19 from 0x2 (RGB) to 0x3 (paletted)
  to enjoy the hidden picture.
  Extra efforts were taken to make the picture not trivial to extract,
  and remove as many artifacts as possible

  by Philippe Teuwen & Ange Albertini, original idea by Dominique Bongard

- 2.bmp is a BMP/PCM polyglot, which means it's a Bitmap picture,
  and a RAW audio polyglot that is directly playable
  (it's not really hidden, it's just happy co-existence).
  The audio, when viewed in spectrogram view, will show a familiar face.

  To enjoy it fully, just run
  sox -t raw -r 44100 -c 1 -e signed -b 32 2.bmp -n spectrogram
  (with optional -m -x 555 -y 512 -z 24 -Z -36, for better rendering)

  For more details, check http://wiki.yobi.be/wiki/BMP_PCM_polyglot,
  including a nifty RGB spectrogram via baudline.

  by Philippe Teuwen & Ange Albertini

For PNG in PNG, see PNG Merge
For BMP/PCM, see BMP PCM polyglot

PoC||GTFO 0x06 contains also a scan of a softstrip

PoC||GTFO 0x07

PoC||GTFO 0x08

  • Animated covers
    • @pdfkungfoo made lovely gifs for those of you not having Adobe to enjoy last PoC||GTFO 0x08

(click them to see the animations)
Also as video: https://vimeo.com/131434211 and https://vimeo.com/131445216


Misc in the same PoC spirit

Ange had fun with Cameron recent declarations: https://imgur.com/xNUlzaE
That PNG contains a dummy chunk ("dumb" chunk actually) with 32b PCM so you can actually play the PNG and hear the content of dumb chunk (before hearing the white noise of the picture data itself)

wget -O - https://imgur.com/download/xNUlzaE | aplay -r 44100 -c1 -f S32_BE

Note that we're supposed to apply a ROT13 but I don't hear a difference (rot13 on binary only affects slightly a small part of the range)

wget -O - https://imgur.com/download/xNUlzaE | tr '[A-Za-z]' '[N-ZA-Mn-za-m]' |aplay -r 44100 -c1 -f S32_BE

The voice says "I've no idea what I'm saying"