Add simple helper functions for encrypting & decrypting content

[cinnamon-bun]

This issue is duplicated by #10

What's the problem you want solved?

Users have public keys, let's send them some private messages! Or eventually, encrypt messages to the workspace public key so only people with the workspace private key can read it (e.g. the members of the invite-only workspace).

Complicated solution

#11 Fully wrapped encrypted documents

Easy solution

Just encrypt the content and nothing else. The path and author will be exposed.

The recipient could be specified in the path so they know where to look for messages, or we could make recipients scan through everything looking for documents they can decrypt.

The encryption can probably be done with some function in Chloride. For multi-recipient messages we can use private-box

Potential crypto modules we can use:

Todo

• Research how to do basic message encryption with Chloride
• Write a helper function in crypto.ts
• Think about how this affects IStores -- will they try to decrypt stuff for you? How do they know what to try? Should an IStore become responsible for one specific author's decrypted view of the data, or stay neutral? Maybe this is an app-level concern?

[jb33k]

How close are you at implementing this? I'm mainly wondering whether I should do a userland e2e or wait for native support.

[cinnamon-bun]

@jb33k

I won't get to this in the next couple of weeks at least. This is really just a matter of finding the right functions from chloride and exporting them so people in userland can easily encrypt their document's content field by hand. It won't be something deeply integrated (...yet, that's #11 which will be Later).

If you do it yourself and want to share your code, that would be helpful!

[jb33k]

@cinnamon-bun

I use Sodium directly for crypto, so unfortunately I have no experience with chloride. Personally I'm planning to go with ChaCha20-Poly1305 for AEAD. Btw, when you get around to implement the encryption, you should plan to implement streaming with WASM because otherwise performance will be unbearable for anything more than small text files, especially with mobile. But the issue I've run into is that there is no ChaCha20-Poly1305 WASM implementation that I have found that supports streaming out-of-the-box.