Easy

They keep secrets locked away. And you pass through them each day. For each one there is a key, They respond to sesame.

related riddles

I am neither a guest nor a trespasser in this place. I belong that belongs to me. Where is it?

I have joy in bringing two together, but darning my existence! My life hangs by a thread, filled with ups, downs and resistance!

The more you take away, the bigger it gets.