Shmoocon 2011 Crypto Challenge Pack

The Ghost In The Shellcode organizers gave me the privilege again this year to write some challenges for their CTF event. Here are the contents of the README:



Shmoocon 2011 Cryptography Challenge Pack
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http://www.ghostintheshellcode.com/
https://www.shmoocon.org/ghost_in_the_shellcode
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These are the cryptography challenges submitted to the Shmoocon 2011 "Ghost In
The Shellcode" organizers for potential use in the CTF event and December
qualifier.
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Challenges were made with a few features to facilitate analysis:
1) open source (skip the disassembly->algorithm translation phase)
2) calculations, input, output are all in decimal, allowing easy entry of
values between external tools
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Python?
1) seems program logic is easy to understand even without knowing Python
2) debugger is easy to use (python -mpdb chall1.py) but you probably won't need
it
3) installs nearly everywhere
4) tested with 2.6.5
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I hope you find these algorithms easy to understand, interesting, but
challenging to keygen. Chall4 and Chall5 are exceptions :)

http://crackmes.de/users/andrewl.us/shmoocon_2011_crypto_challenge_pack/