COD 4 Network protocol specification

[Horkyze]

Hello, I am interested in the format, how server communicates with clients. I know that Quake3 protocol is used for RCON. I coded application in Java, for kicking player from server and stuff. Basically it was just about sending the right UDP packet. All comunication was plain-text, so nothing exciting. But it was my first network app, I am proud for it.

Now I want to move to higher level. I was thinking about sniffing traffic on my local machine, getting other players location (and other info) and displaying it.
Problem is, when I take a look at the packet it is not plain-text.

I have no idea what alg. is used to compress || encrypt the packet. Before doing the hardcore reverse-engineering I was wondering someone may save my time.

Many thanks