Security system turned on

I have just bought a 1994 Camry CSI (made in 11/1994), which has a security system and a FM/AM/Casette system. When I changed the batter, I can no longer used this casette system as the letters "SEC" appeared in the screen of it. I had read through the logbook of the car, which says that I have to enter the security code to make the casette work again. However, the seller has no idea about this code. I wonder there is any way that I can use to solve it? Help me please! Many thanks.

It's my belief that if you call your local toyota dealer with the vin of the vehicle and can prove ownership they can give you the code.