This is the solution of the challenge “ChatWithPico” from Ph0wn 2023 CTF we solved together with @FdLSifu. It was an interaction with a chatGPT prompt well protected to avoid secret leakage and including a small reverse engineering task.

A recent feature of Jadx allows to easily hook functions in Frida.

This is the solution of the challenge “Schnorr Signatures” from Black Alps 2023 CTF. It was Schnorr signatures with a known prefix of 128 bits set to zero.

This is the solution of the challenge “Spooky Safebox” from Hack.lu 2023 CTF. It was a ECDSA signature with a known prefix but with a limited number of signatures. Applying the Bounded Distance Decoding with Predicate algorithm allows to recover the private key.

This is the solution of the challenge “Baby RSA” from CCCamp 2023. It was a RSA whitebox implementation in Python with a left to right windowed exponentiation.

This is the solution of the challenge “HR Complaints” from NorthSec 2023. It was an exploitation of the ROCA vulnerability on a 512-bit long RSA key.