CryptPad

Summary

CryptPad is a collaborative document suite with client-side, end-to-end encryption. Its implementation encrypts content in the browser before sending it to the server. Collaboration and confidentiality are separate design choices; see local-first software and CRDTs for that distinction.

How it works

Clients exchange encrypted document changes through an instance. The project provides the source code and an administrator guide for installing and maintaining your own instance. Self-hosting chooses who operates the service; it also assigns you the work of configuring, updating and maintaining it.

Trust model / threat model

The security guide explicitly requires trusting the chosen instance to deliver the published code and carry network messages. Under those assumptions the instance cannot read document contents. A server that supplies altered browser code breaks that assumption.

The instance can still see the user's IP address and browser/operating-system information. CryptPad calls this only weak anonymity. Collaborators must also be trusted with sharing links: forwarding a link can give another person access. The guide documents passwords as an additional protection when a sharing link crosses an insecure channel.

Readiness

Usable. The project publishes user documentation, production installation instructions and its implementation. Use the production guide for a real instance; a development configuration is not a production deployment.

Limits

Encryption is not a promise of uninterrupted availability or recovery from every mistaken deletion. Plan separate recovery arrangements for important work; see Private file sync and backup and decentralized storage.

Primary sources

• CryptPad project
• Security assumptions, metadata and sharing links
• Administrator guide
• Implementation and production deployment guidance

Also in Secure Messaging