2026-07-01 –, Amphitheater 122
CryptPad is an open-source end-to-end encrypted collaborative office suite focusing on being easy to use and protecting the privacy of its user, including from the service provider itself.
While security against a quantum adversary becomes more and more relevant, we experimented on the realisability of Post-Quantum CryptPad. This talk will expose how cryptography is used inside CryptPad, our methodology and the results of these experiments.
CryptPad is an open-source end-to-end encrypted (E2EE) collaborative office suite. It enables secure collaboration between users without the service owner knowledgable about the content of their documents. It has been designed to be secure from login to document sharing… with even the internal support system being E2EE.
This architecture is by design interlaced with cryptographic constructions. Meanwhile, the deployment of quantum resilient solutions are becoming more and more urgent, especially in the context of encryption (as they can be targeted by “harvest-now-decrypt-later” attacks, while authentication cannot be forged a posteriori). In this context, we explored the different implementations of post-quantum standards selected by the NIST post-quantum cryptography standardisation process.
After careful consideration of the different candidates for both encryption and signature, we integrated crypto-agility solutions in CryptPad. This was done both for the advantages from a security and software engineering standpoint, and to be able to easily switch between traditional and post-quantum solutions for testing.
In this talk, we will first present how CryptPad works, then expose the different challenges we faced during the experiments, and finally show the results of these aforementioned post-quantum experiments from a performance and usability point of view.
Fabrice started as a cryptography researcher working on post-quantum and classical construction for privacy-preserving constructions. He joined the CryptPad team in 2023 to work on a cryptography-first open-source product and make cryptography accessible to most people.