When talking about Skype I usually mention that Skype is one of the few IM clients out there that has great encryption built into it. Due to it’s peer to peer hybrid structure encrypting data while sending it through the p2p network is very important, and Skype has some pretty advanced encryption algorithms in use.

But, guess what?
You won’t notice that somebody is spying on your Skype conversations if your Skype login information has been disclosed.

I noticed this after leaving my computer running while going to university today, and the IM conversation I had with Mathias was not only delivered to my laptop but also to my home computer. Completely unnoticeable (from the laptop) my home PC received the whole conversation, so a 2 way IM session could have been a 3 person chat session with only 2 nicknames. Weird isn’t it?

This behavior is especially dangerous if you think about how most users pick and protect their passwords.