Nowadays, when people talk about an EGP routing protocol, they aren't talking about the protocol called EGP. It went out of vogue a loong time ago. Insetad, they are talking of a class of protocols- External Gateway Protocol.

These are used to talk to other autonomous systems (think ISPs).

Today, there is only one modern EGP in existance, and thats BGPv4. But BGP is a 'meta-protocol' in such that it needs an IGP (internal gateway protocol) to actually send network topology data between your routers, assuming your net is more than one hop wide.

But judging from your post, this isnt the case. You have a unix machine which partakes in your networks' routing decisions, maybe because you have several interfaces? so you can have a dynamic routing table right?

RIP isn't insecure in itself. Perhaps you should just add some firewall rules which says that UDP to port 520 can only come from your friends' ip addresses? or your own net?

A rather long-winded reply, but hope I shed a little light on your question.