Changes

Note that a verification usually requires that you exchange information with your contact. Don't exchange it using the same chat, because you could in fact be talking to the MITM. If you exchange the verification information over the the internet, that channel might be controlled by a MITM, too. So a reliable verification requires that you use a different channel for verification, such as meeting in person, or calling on the phone, or using encrypted/signed email, with known correct keys.