Bochum Challenges

Welcome!

The purpose of our Bochum Challenges is to encourage cryptanalysis of medium-sized instances of post-quantum schemes, in order to get more confidence in the reliability of current security estimates.

We explicitly focus on feasible challenge parameter sets to stimulate real-world cryptanalysis research in this field. We started our project with challenges for the lattice-based NIST encryption standard Kyber, but will regularly enhance our challenges with down-scaled parameter sets for cryptographic schemes of real world significance.

In 2025, we released challenges for the Mayo signature scheme and the McEliece encryption scheme. We will continue to release challenges for other post-quantum schemes in the future.

Although we consider a parameter set solved when you recover its secret key, for the fun of cryptanalysis we strongly encourage you to also decode our challenge ciphertext into a (meaningful) message.
For our signature scheme challenges, we ask you to forge a signature. More details can be found in the respective challenge descriptions.

Changelog
2025-09-26 Mayo Challenges
2025-09-26 McEliece Challenges
2023-06-27 Kyber Challenges

Citation

You can use the following BibTeX snippet to cite and refer to this page:

@misc{bochum-challenges,
  title = {Bochum Challenges},
  author = {The {Bochum Challenges} Team},
  url = {https://bochum-challeng.es},
  note = {Available at \url{https://bochum-challeng.es}},
  year = 2025,
  month = oct,
}