Flat Key Profile Asymmetry for Electro-Picking Resistance
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Solution Overview
Problem
Existing key profiles are inadequate in providing effective copy protection and resistance to electro-picking attacks, as they do not sufficiently intercept or block the movement of pick fingers in keyways.
Innovation Solution
A key profile with wedge-shaped features on the side surfaces of the key shank, where the profile base is wedge-shaped towards the key channel's back and the upper surface is horizontal, combined with paracentric features and catch grooves, to guide and block the pick finger's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional key profiles are used, then manufacturing is simple, but copy protection and electro-picking resistance are insufficient
Solution Approach 1:
The patent applies asymmetry by designing profile features with a wedge-shaped base (inclined at angle α) and a horizontal upper surface, creating an asymmetric geometry that effectively blocks electro-picking attempts. This asymmetric design causes the pick finger to be guided away on upward movement and blocked on downward movement, providing superior electro-picking resistance while maintaining manufacturability through standard machining operations.
2Reliability
If wedge-shaped profile features are implemented, then electro-picking resistance improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a wedge angle α of at least 25°, which has been determined to be optimal for providing adequate electro-picking resistance. This parameter specification balances the need for effective pick interception with manufacturability, as the angle is large enough to be effective but not so steep as to require excessive manufacturing precision. The horizontal upper surface further simplifies manufacturing while maintaining the wedge's protective function.
Data Source
Figure 1
AI summary
The invention relates to a key profile for flat keys, which is formed on the side surfaces of the key shaft and interacts with a corresponding profile in the keyway of a cylinder core (1) rotatably mounted in the lock cylinder housing. The profile of the keyway has profile features whose base (4, 5) extends wedge-shaped towards the recess in the keyway that receives the back of the key, and whose upper surface facing the recess is essentially horizontal with respect to the longitudinal plane of the key.