Is there such a thing as a lock that bolt cutters can not cut through?
But it might not fit the application you want. A U-Lock is a yoke-and-bold design like this Kryptonite model: They are designed for bicycles in high-crime areas – most of the bike messengers in downtown Chicago have them. They are made of aircraft-grade aluminum that is hardened and tempered so as to be nearly impervious to a hacksaw, and the tubing is too fat for a bolt cutter. I have seen them used for other applications, like locking gates and double doors, but something like this is too big to be used in place of a padlock with a conventional hasp. This is not to say there are no good padlocks. You don’t want a model that can be cut with any bolt cutter that’s small enough to conceal under a long coat. You might also consider a model like this, from Master Lock: It has a protected shackle that should foil most a
