Currently, the client assumes the server's public key is correct the first time they connect. This isn't a horrible assumption to make as in most cases it will be, but it leaves rooms for MITM attacks in specific scenarios.

The circumstances for this to be a problem are the following:

• the user has already created a server connected to the internet and already has data on it
• the user is connected to an untrustworthy network (such as a public wifi)
• the user is logging in on a device which never connected to the server
• the owners of the untrustworthy network are targeting specifically PMP

While this is unlikely to happen, it should still be fixed. There should be a human-readable version of the public key which the user should confirm.