Engine won't start. Looking for other causes.

What is your question?

My Corolla's engine will not turn on. When the key is turned, you hear nothing (not even a crank). The starter was checked and it was working fine. Fuses were checked and they were fine. Ignition cylinder (where the key enters the ignition) is not broken. Auto mechanic friend believes it could have something to do with the factory security system. Please advise.