Linux support

[aidansteele]

Would you be interested in a PR that adds support for Linux? Things that would need to change would be references to CommonCrypto and the Keychain. I'd be happy to do such work, just want to check it's something you might be interested in reviewing.

[mattrubin]

I haven't had the bandwidth to tackle this myself, but I'd definitely be interested in reviewing some PRs to add Linux support. I think you've correctly identified the two things that would need to change, but the core functionality should be able to remain the same.