I’m trying to create a web app that involves sharing of user-generated content, but one of the goals is that the service host operator should be blind to the content. Only authorized users should be able to see the content shared with them. This implies the content must be encrypted at rest, and users must hold custody of their private signing key.

I figure the situation requires an open source browser extension to hold onto a user’s keys and decrypt content for them. The web app would still be able to browse all of the site’s metadata, but any plaintext content must be siloed in the extension. The reason for using an extension is that the source code would be open source and independently verifiable, while building the same functionality into the web app would require trusting the host to serve the code you expect.

Do you think that’s a reasonable tradeoff or is this asking too much from users?

The other option would be just requiring users to download an open source app for content viewing.

EDIT: Perhaps an important followup: are you OK placing trust in the host to never access your confidential data if it means you don’t have to install additional client software or worry about verifying that client software’s authenticity?

  • paks@feddit.uk
    1·
    3 days ago

    Something along these lines is a good idea, but be aware you need extra considerations to keep the e2ee intact. If like most websites you would send the password to the server to login, and if you derive the private key from the password, suddenly the server would have your private key.

    There’s probably something you can do with hashing before sending to the server on login, but I don’t have enough confidence to be definitive on that.