Local (and remote) file storage encryption is doable with nostr too, here's an article with an early architecture, we made a lot of progress since, but I haven't made an update post yet.

Check it out and please give some feedback.

nostr:naddr1qqgrsde5xcexzvny8qerjvf3vgmkxqg3waehxw309ahx7um5wgh8w6twv5hsyg9ha45tqck7dd9p9egl6559c8s7pmgw2y5vm2f6kyd5z594tmfjlspsgqqqw4rs37vdn7