What Information Does A Locksmith Need In Order To Key A Lock?

I am having difficulty preventing people from entering my apartment. I have purchased pickproof locks, but they still get in. I can only conclude that a locksmith is involved and is cutting a key for my locks. Do they have to know the brand of lock in order to cut a key? I had a open house today, but was not invited, if you catch my drift.


Tempe Lock and Keysmith 4000 South Rural Road, Tempe, AZ Phone (480) 270-8688‎