Generating Rogue Certificate Via Finding Hash Collisions

CMU 18733 Mini Project (Spring 2017)

Brief:

The idea of "rogue certificate" attack proposed by Sotirov et. al. in this presentation shows that the attacker is able to obtain a valid certificate for a rogue intermediate CA, which includes the certificate that is allowed to be used to endorse ither certificate, giving attackers virtually unlimited power. This mini-project aims to generate a rougue certificate by replacing certain fields of a valid endorsed certificate such that the entire hash remains unchanged. This means the signatures on the old certificate will be same as that on the new.

Getting Started:

Installing Z3 SMT Solver:

See https://github.com/Z3Prover/z3

Run:

sudo python main.py

SHA:

The SHA used in this mini project is a simplified version of SHA-256, named SHA-256-18, where only 18 rounds and special padding scheme has been removed. The full version of SHA-256-18 can be referred to sha256_template.py.