Modern mechanical locks allow the binding mechanism (that prevents an open) to interface with the input mechanism (that "reads" the key or pick input into the system). This allows lockingpicking, raking, and other attempts to move the lock elements into the appropriate position, because the input system gives physical feedback/resistance that allows a skilled attacker to manipulate the pins or lock elements 1-by-1 until he finds a valid input.
Lockpickinglawyer's kwikset improvement video (
https://www.youtube.com/watch?v=7JlgKCUqzA0 ) gave me an idea for an improvement to modern locks that doesn't involve too much additional complexity
His system has multiple wrong inputs (i.e. lifting pins without a wafer to slide over his construction holes) and those wrong inputs deny entry. Critically, there is no feedback when inputting the "combination" of pin heights into the lock - only when the core (and everything the attacker can access non-destructively) is turned is there physical feedback that the "combination" of pin heights was incorrect.
I think the improvement is to take this idea (the key inputs a combination of heights, which are then checked after core rotation starts) and apply it without freezing up the lock and simply make sure you have enough permutations in the lock settings to allow adequate security
I have two ideas for how to do this without freezing up the lock
1: On top of your driver pin you have a stack of wafers, the top one of which is double height and extends across the shear line when resting. There are some number of normal wafers below, which can be lifted into the bible, allowing either: 1 wafer (clearing the double-height wafer from the shear line), or 2 or 3 or X (however high your stack is, presumably 3ish) to be "input" as valid key heights and will not give physical feedback. Once the wafers are lifted, they sit in the bible. Now, for the next step, the bible has to be a metal frame that allows some sort of comb (attached to the core) to pass through. This comb will be shaped so that the double-height wafer can only be at a certain height (i.e. there is one double-spaced gap for a wafer to go through, but not two). If the wrong number of wafers are lifted prior to core rotation, the double-height wafer will not line up with its 1 and only hole, and block the further core rotation.
2: Instead the bible can have holes drilled in the sides and have wafers that do or don't have holes in them to allows metal tines/spikes through. This probably requires non-round pins in order to keep the hole aligned properly. Probably also restricts the number of differs, but you can just add more pins to up the math on the number of permutations.
