0CTF 2018 Quals – zer0TC (Crypto 916)

0ops Toy Cipher, hope you enjoy it:) zer0TC.zip Summary: meet-in-the-middle and key-schedule constraints


0CTF 2017 Quals – Zer0llvm

Talent Yang loves to customize his own obfuscator. Unfortunately, he lost his seed when he was watching Arsenal’s UEFA game. What a sad day! His team and his seed were lost together. To save him, could you help him to get back his seed? We can not save the game, but we may be able… Continue reading »


HITCON CTF QUALS 2016 – Reverse (Reverse + PPC 500)

At least our ETA is better than M$. http://xkcd.com/612/ reverse.bin Summary: optimizing an algorithm using Treap data structure and CRC32 properties.


Google CTF – Jekyll (Crypto)

Can you access the admin page? You can look at the crypto here. source.py Summary: finding a preimage for a simple 64-bit ARX-based hash.


Hack.lu 2012 CTF Challenge #3 (450)

3 – Zombies like PPTP Our intel shows us that the Zombies use a MS-PPTP like protocol and luckily we could intercept a challenge-response transmission of one of the Zombie outposts. The important thing for Zombies in this war is mass! Not only brain mass but their mass. So they built their PPTP protocol compatible… Continue reading »


PlaidCTF 2011 #20 – C++ upgrade (300)

Category: pwnables They have an update for the vulnerable C++ program trying to fix the bug. However, the coders at AED suck and introduced another stupid mistake. Get a shell (and the key, too.) ssh username@a5.amalgamated.biz Username: cpp2_1 Password: zKQaKrdFPSsT6j03XSt31NaT0H Summary: tricky overflow class’ method and exec’ing symlinks binary