Core-Sleeve Lock Assembly With Decoy Shear Lines Against Picking
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Solution Overview
Problem
Pin tumbler lock cylinders are susceptible to attacks such as picking and bumping, as they rely on manipulating rotational torque and sensing cylinder pin positions, leading to vulnerabilities that existing security measures have not adequately addressed.
Innovation Solution
A pick-resistant lock assembly with a housing and core-sleeve mechanism featuring multiple pin stacks, decoy shear lines, and a true shear line, where only one true shear line out of many possible combinations allows the core and sleeve to rotate, making it extremely difficult to pick successfully.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pin tumbler lock cylinders are used, then the structure is simple and easy to manufacture, but they are susceptible to picking and bumping attacks
Solution Approach 1:
The lock assembly is segmented into multiple independent pin stacks (at least 5), each containing multiple pins (at least 3 per stack). This segmentation creates multiple separate security barriers, where each pin stack must be independently manipulated to achieve lock activation, significantly increasing the complexity of picking attacks while maintaining manageable manufacturing processes for each individual pin stack component.
Solution Approach 2:
The invention introduces multiple shear lines (first shear line and second shear line) at different vertical positions within the pin stacks, creating a multi-dimensional security landscape. The first shear line is positioned between the first and second pins, while the second shear line is positioned between the second and third pins. This vertical dimensionality means attackers must simultaneously manipulate pins at multiple different heights, transforming a traditional single-plane picking problem into a multi-level spatial challenge that dramatically reduces successful attack probability to 1 in 32,768.
2Reliability
If multiple pin stacks with multiple pins per stack are implemented, then pick resistance is significantly increased, but manufacturing complexity and cost increase
Solution Approach 1:
The housing is designed with a universal chamber structure that can accommodate multiple pin stacks using identical or similar pin configurations. Each pin stack uses the same basic components (pins, springs, shear lines) arranged in standardized patterns, allowing manufacturers to produce identical pin stack assemblies in bulk and simply install them in different positions within the housing, significantly reducing overall manufacturing complexity despite the increased number of components.
Solution Approach 2:
The pin stacks are nested within a standardized housing chamber that provides a uniform interface for all pin assemblies. The housing chamber is designed to contain and organize multiple pin stacks in a compact arrangement, with each pin stack fitting into its designated space within the same housing structure. This nesting approach allows for modular manufacturing where pin stacks can be pre-assembled and then installed into the housing as complete units, streamlining the manufacturing process.
3Difficulty of detecting and measuring
If decoy shear lines are added to increase security, then the difficulty of detecting the true shear line increases, but the device complexity increases
Solution Approach 1:
The invention creates multiple copies of shear line structures at different positions within each pin stack. The first shear line and second shear line are essentially copied versions of the same basic shear interface, positioned at different vertical levels. These copied shear lines serve as decoys that mimic the appearance and function of a valid shear line, forcing attackers to differentiate between authentic and fraudulent shear lines based on subtle structural differences in pin configurations and spring tensions, thereby significantly increasing detection difficulty while using relatively simple replicated components.
Data Source
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AI summary
A pick resistant lock assembly is provided. The lock assembly includes a housing having a main bore and a chamber including a plurality of channels holding a corresponding plurality of pin stacks, a core having a keyway and having a plurality of core openings configured to align with the channels of the housing, and a sleeve configured to fit within the main bore. The pin stacks are each configured to provide a plurality of decoy shear lines in which rotation of the core and the sleeve together is limited by a blocking position and a true shear line which permits rotation of the core and the sleeve together for actuation of the lock assembly when the true shear line is provided in each pin stack of the plurality of pin stacks.