A workshop for the Lean community - Thursday, March 12, 2026

We’re pleased to announce the PSQ protocol for establishing a hybrid post-quantum shared secret between two parties. Cryptographic protocols, which exclusively rely on classical public key…

Jobs at Cryspen. Browse all our open positions and become part of our growing team! We are currently looking for additions to our company. Apply today!

In this post, we are going to use hax and F* to verify a small real world Rust crate. Then, we will try other verification tools (Kani, Verus, Aeneas) to the same thing. The Rust crate gcd by Corey…

We welcome Alex to Cryspen

22. escar Europe - November 19 to 20, 2024, Dortmund (Germany)

Cryspen found and fixed bugs in the Rust SIMD libraries using formal specs

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OpenSSL Conference Prague 2025 | October 7-9, 2025

Cryspen worked with Signal to formally analyze their new post-quantum ratchet

Real World Crypto Symposium

Recent years have seen several landmark results in the formal verification of high-performance cryptographic libraries, leading to verified crypto code being adopted by mainstream projects like…

MTG and Cryspen release JZLint 2.0: A tool for analyzing post-quantum certificates

Wavestone, en partenariat avec Bpifrance, a le plaisir de publier son Radar de l’innovation cybersécurité français 2025.

Orange Meets, our open-source video calling web application, now supports end-to-end encryption using the MLS protocol with continuous group key agreement

The Messaging Layer Security (MLS) protocol standard proposes a novel tree-based protocol that enables efficient end-to-end encrypted messaging over large groups with thousands of members. Its…

A Warm Welcome to Clement, Our Newest Cryspen Crew Member!

In April, we successfully merged 38 pull requests!

What are state forks, why can’t they happen but do anyway and how can they be resolved in OpenMLS?

A careful treatment of identifiers lies at the heart of all code analysis frameworks, and we hope our experience here proves useful to others.

In March, we successfully merged 32 pull requests!

Real World Crypto 2025 buzzed with energy as the cutting edge of cryptography was presented to and discussed among an audience of leading researchers and developers from academia and industry. Today,…

A difficulty of formal verification is that specifying programs can be hard. Certain kinds of programs can end up having a specification that is as complex as the code itself. In this case it is…

Real World Crypto Symposium

The hax toolchain has been successfully used to formally verify our cryptographic implementations for ML-KEM,Bertie and more. All these projects are developed with formal verification (using hax) in…

A Warm Welcome to Clara, Our Newest Cryspen Crew Member!

Cyberattacks on companies and public institutions are increasing dramatically worldwide. The PROTECT project, funded by the Cyberagentur, is developing solutions to enhance the resilience of IT system...

We're thrilled to announce that hax is entering a new era of stability and growth with the launch of our new website, a fresh start at Cryspen, and our first official release, v0.1.0!

Work with us

Mini-C is a subset of C that can be automatically turned to Rust without much fuss

Despite some team members attending an offsite work week event, we merged 24 PRs this month. Here’s an overview of the work of the month. The frontend remained stable this month, with only a few pull ...

Where the Berlin Crypto Community gets together.

Jobs at Cryspen. Browse all our open positions and become part of our growing team! We are currently looking for additions to our company. Apply today!

Karthik gave an invited talk on High Assurance Post-Quantum Cryptography at VSTTE 2024.

October 14-15, 2024, Prague, Czech Republic Co-located with Formal Methods in Computer-Aided Design 2024 (FMCAD 2024)

In July, we merged 33 PRs! 🎉 On the side of the frontend, Nadrieril and I worked at making hax handling of binders (e.g. 'a in for<'a> &'a T: PartialEq<i32>) and traits better. This is not finished ye...

When implementing cryptographic protocols, probably the most important thing is to not forget validating all inputs. Failing to do so can lead to inadvertant leakage of private information, state…

IoT meets Secure Supply Chain, 30.9.-4.10.2024 in Paris, France