You should read the docs. It’s impressive.

I get where you’re coming from, but after readinhow badly security is implemented in iMessage frankly I trust the Beeper devs more than Apple.

Get this, iMessage delivers the AES encrypted message in a package with the AES key, that package is encrypted with your RSA key.

iMessage lacks forward secrecy. So if anyone ever got your RSA key, they could read all your messages, including past messages, because your RSA key never changes!