A wormhole generator is fabricated in a factory. It will be comprised of two identical Hole Punches, one of which is dropped at each end of the intended "tunnel". Through an exceptionally focused, massive, and complicated set of gravitational and quantum fields, each Punch twists a hole in the surface of space, similar to a rotating black hole or singularity. The two Punches must be dropped, calibrated, and synchronized by an incredibly specialized ship. Both components need to be dropped by the same ship, which then resonantly calibrates both generators so that a skin of space forms between the holes. Ships propel themselves along this skin with standard propulsion drives... the Wormhole Key just keeps them from being torn to bits as they come within proximity of the wormhole and related fields that create it.

The Holes generate massive distortions in very close proximity to themselves. Ships wishing to use the wormhole need a Wormhole Key, which is comprised of a specialized set of hardware and software that feeds a battery of 13-dimensional information about the physical characteristics of the generators, the fields they produce, and the wormhole itself. The "soft" part of the key changes constantly but predictably based on the physical and quantum properties of the wormhole and generator. Keys are generally either privately distributed by whoever lays the wormhole or broadcast publicly or privately by the generator itself. Keys can be calculated but the necessary computing and scanning resources are considerable and specialized. To decode an unknown Wormhole Key requires parking these resources right beside the Wormhole for a considerable period of time.

Wormhole Ettiquette
You don't just go sticking your Wormhole any old place you choose. When placing Wormholes in a system controlled by a foreign government, there are certain conventions that are generally followed. You are expected to provide a "refueling facility" which will provide services including basic lodging, refueling, restocking, and repair capabilities as well as emergency management crews. The refueling base also needs to be able to provide traffic control and maintain order if the hole becomes busy. 

Taxes and levies for placing the hole are negotiated and paid by the government or organization laying the wormhole as well as by ships passing through, based on factors like tonnage, ship function, and cargo. In most cases, the government controlling the system will insist that they be provided with the key. If the key is to be publicly broadcast, the host government will generally insist on some form of regulation of the traffic allowed to use the wormhole to prevent activities like invasion and smuggling.