Cryptpad: An open-source end-to-end encrypted collaborative document editor

Collaborative document editing is a great tool that is useful to edit a document with real-time feedbacks on what other collaborators are changing. From the users point of view, it allows always having the last version of the document and limits the risk of overwritting what have already been made. However, the documents that are edited in this fashion may contain sensitive information, that users don't want to share with the service provider, henceforth the use of cryptography to protect these data from external agents.

Cryptpad propose a solution to reconcile both world by providing a user-friendly solution to edit their documents, while their browser decrypts the messages sent by other collaborators to incorporate their change while the server remains oblivious to the content of their exchange.

In this presentation, we will define our threat model and how the cryptography underlying cryptpad is working, how these design choices influence the user experience and future directions.