2003 Toyota Camry immobiliser system

I have a 2003 Camry which I purchased used. I believe the car is equipped with the immobiliser system. The car has been running great until yesterday. I went to start the car and the alarm went off and the engine would not turnover. I have tried everything(turning the alarm off with the key fob, using a second key… no luck) any ideas on how to proceed?

Thanks, DB