Anti-theft Kill Switch

[camaro1969]

I would like to install a on.off switch to prevent theft. I want to have a cut off switch to an electrical source that will not let the car start unless the switch is turned on. Any idea where i can bypass a source to have this work without the thief knowing how to get past it? Will bypassing the solenoid wire to the starter work?

Any set up by sponsors made to have a little more sophistication than just an on/off switch? I know fesler has a kill switch, but it is a time switch, which kills the car after 90 seconds.. any other takers who make a quality set up?