cryptohard

Flux Key

ASIS CTF

Task: NLFSR-based block cipher with IV-dependent nonlinearity. Solution: Set IV=0xFFFFFFFF to linearize cipher, then recover 64-bit key via Gaussian elimination over GF(2) using decryption oracle pairs.

$ ls tags/ techniques/

linear_cryptanalysis keeloq nlfsr chosen_iv_attack gaussian_elimination gf2 block_cipher decryption_oracle symmetric_cipher

Linear cryptanalysis with chosen IVGaussian elimination over GF(2)Decryption oracle exploitationKey recovery via linear equations

Analysis

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

$ python3 exploit.py --target 192.168.1.1 --port 8080
[*] Connecting to target...
[+] Shell obtained!

Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

🔒

Permission denied (requires tier.pro)

Sign in to access full writeups

Create a free account with GitHub, then upgrade to Pro.

$ssh [email protected]