Originally Posted by
Monster Pete
..or a set of vise grips clamped to the outer surface. I'd just go for a regular bolted axle.
There isn't a set of locking skewers made that can't be overcome fairly easily. The Zefal ones are disabled by a magnet, Pitlocks by a flat-head screwdriver, and these with vice grips. Security isn't about making theft impossible, it's about raising the risks associated with it.