There isn't *the* key, SimpleX isn't nostr, the concept of digital identity is much more refined in SimpleX, there is a multitude of keys.

That's why you need the whole database, in addition to your contacts and messages it has your gazillion keys in them.

Not that I like that, I think it should be possible to reduce it all to just a few keys for the identity and one for each contact.

Stuff you can print out on a piece of paper if need be. This should be enough to at least re-bootstrap your network after a catastrophic loss.