A few locks like you describe are Enclave, andy pugh's, Built Different Design's, Carl L. Lambert's, and Michel Robert's.

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Animats 2 days ago | parent [-]

Right. Several of those use stacks of little discs instead of balls. More compact, but if one of those discs gets turned sideways, the lock is jammed.

Pick-resistant locks have two known problems. First, if they have to fit inside a traditional lock cylinder space, the options are very limited. If you're willing to have a bigger lock body, pick resistance isn't as hard.

The second is more subtle. Pin-tumbler locks, as they wear, become easier to open. The pins wear and become rounded. Pick resistance decreases, but you don't get locked out. Some high-security designs fail in the direction of staying locked, even with a valid key. So either you have angry customers locked out, or everything has to be made in stainless steel with high precision at high cost. (That's Abloy.)

	▲	Veedrac 2 days ago \| parent [-]
		I broadly agree those are good to consider (a typical requirement for my own designs is to fit the KIK format as-is), but I think you're being a little too absolute. Enclave deserves some recognition here for getting pretty close. It's just a sidebar and a cam, totally normal lock components. The simpler cylinder-in-cylinder designs are also mostly just hardware that multi-shearline locks already have for master keying.