im working on a javascript UI framework for personal projects and im trying to create something like a React-hook that handles “encrypted at rest”.

the react-hook is described in more detail here. id like to extend its functionality to have encrypted persistant data. my approach is the following and it would be great if you could follow along and let me know if im doing something wrong. all advice is apprciated.

im using indexedDB to store the data. i created some basic functionality to automatically persist and rehydrate data. im now investigating password-encrypting the data with javascript using the browser cryptography api.

i have a PR here you can test out on codespaces or clone, but tldr: i encrypt before saving and decrypt when loading. this seems to be working as expected. i will also encrypt/decrypt the event listeners im using and this should keep it safe from anything like browser extensions from listening to events.

the password is something the user will have to put in themselves at part of some init() process. i havent created an input for this yet, so its hardcoded. this is then used to encrypt/decrypt the data.

i would persist the unencrypted salt to indexedDB because this is then used to generate the key.

i think i am almost done with this functionality, but id like advice on anything ive overlooked or things too keep-in-mind. id like to make the storage as secure as possible.

  • oldfart
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    7 days ago

    I’m not sure if your crypto library does that for you, but I can’t see any code for integrity (encrypt-then-MAC). Not a cryptographer but I remember that’s important.

    Also maybe instead of rolling your own crypto, use libsodium secretbox or something?