CTF writeups · offensive security
CTF player and security researcher
I take things apart, figure out why they broke, and document the whole mess. This site is my lab notebook: the challenges I solved, the dead ends I hit, and the tricks I want to remember next time.
Fresh solves from the archive
A hardened Merkle-Hellman knapsack: 96 public weights generated as a_i = r·b_i mod q from a tight superincreasing sequence, at density ≈ 0.91 — deliberately just under the 0.9408 CJLOS…
A stego challenge built on visual secret sharing: two images (share1.png, share2.png) from a lighthouse keeper's apprentices. Individually they look like noise; XOR them back together…
A stream cipher built on an LCG, leaking only the high 16 bits of each 64-bit state. The flag is XORed with the low bytes of the state sequence — so recovering the hidden low bits…
Total Recall (SunshineCTF 2026) is a statically linked, stripped x86-64 binary with essentially no code to reuse — but it leaks its own stack address and offers two full-chunk reads,…
The TCTF 2026 challenge behind this folder presents a shell-like service on a remote host (TCP port 23, banner included) that ships with a very restricted command vocabulary. Without any…
This TCTF 2026 crypto service ("Feed the BOX") encrypts every supplied 16-byte block with a custom AES variant under a fixed secret key, handshakes a checksum cryptogram (the key…
Competitions represented in the archive, newest first.
The home-team event: a full slate of pwn, crypto, web, forensics, IoT and mobile challenges.
Cloud, forensics, mobile, pwn and reverse engineering.
Crypto, pwn, steganography and network challenges.
AI, cloud and Android security challenges.
DevSecOps and web security.
Forensics and web.
Web and miscellaneous challenges.
Digital forensics.
Enterprise DFIR.
Web exploitation challenges.
Crypto and web challenges.
Beginner-friendly web challenges.