Your phone's client encrypts it to a public key of the receiver phone's client. The associated decrypting key never leaves that receiving phone (verified by loo

Your phone's client encrypts it to a public key of the receiver phone's client. The associated decrypting key never leaves that receiving phone (verified by looking at the source code). You know it's the correct public key if you check the "security code" thing (not that many people do that, but hopefully enough people do that any tricks would be caught)