Arcane Lock

An arcane lock spell cast upon a door, chest, or portal magically locks it. You can freely pass your own arcane lock without affecting it. If the locked object has a lock, the DC to open that lock increases by 10 while it remains attached to the object. If the object does not have a lock, this spell creates one that can only be opened with a DC 20 Disable Device skill check. A door or object secured with this spell can be opened only by breaking in or with a successful dispel magic or knock spell. Add 10 to the normal DC to break open a door or portal affected by this spell. A knock spell does not remove an arcane lock; it only suppresses the effect for 10 minutes.