How does TeamExtreme MC launcher bypass auth?

Question

I am developing a custom game launcher and as I was looking on how to launch minecraft 1.7.4 it seemed to me that the *.jar cannot be launched without setting an authentication process to the mojang site. However, TeamExtreme minecraft launcher bypasses this. How?

Answer 1

Most likely, it just sends in false data, or empty data. This should allow minecraft to launch in offline mode, meaning that it lets you join but you are not logged in, so that you cannot play on servers.

I am not entirely sure, however, this should send you on the right track.