2001 S-10 Security Light

I searched the forum and can't seem to find the same problem I'm having. Every now and then a security light randomly appears on my dash while I'm driving, yet I have no security system (no power locks or alarm system). What does this mean?
Thanks for any help.

You do have a security system. It's to prevent hot wiring of the truck... That said, it usually ends up either being the key or the cylinder because it can't read the resistance value on the key correctly.