MitM doesn't involve anyone faking how your friends talk -- it's always just passing your actual packets back and forth, but recording them first. E2E encrypti

MitM doesn't involve anyone faking how your friends talk -- it's always just passing your actual packets back and forth, but recording them first. E2E encryption is only as secure as the key exchange, so if the central Skype server gives you and your friend the keys you need to encrypt/decrypt then just passes along your E2E-encrypted packets... anyone who was able to snag the keys and has access to the encrypted packets can decrypt everything just as you can.