Most people would be okay with plaintext content sitting on your server and even publicly accessible by anyone. But this is HN, and we wouldn't use even an AES

Most people would be okay with plaintext content sitting on your server and even publicly accessible by anyone. But this is HN, and we wouldn't use even an AES-512-encrypted service if it has to leave our computers. Our password could still be cracked with enough computing power. So, we'd all be extremely happy if you could make a version for paranoid people like us. Also, I don't know how your indexing works, but please make it easy to backup (just allowing us to define the index folder would do). Possible data loss is the tradeoff with local content.