Hardware Key Generation via Time-Domain Reflectometry
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Solution Overview
Problem
Existing anti-tamper technologies face challenges in effectively concealing encryption and decryption key locations within hardware systems, making them vulnerable to unauthorized access and reverse engineering, especially in systems composed of standard components.
Innovation Solution
The use of hardware-based internal measurement techniques such as time-domain reflectometry (TDR) to embed encryption, decryption, and access key information within system components, ensuring that any changes to the hardware render the system inaccessible and making it difficult to create imitation systems by requiring identical physical characteristics for analysis and testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption keys are stored in hardware components, then data security is improved, but the system becomes vulnerable to reverse engineering and unauthorized access
Solution Approach 1:
The patent extracts the key storage function from traditional secure memory locations and embeds it within the functional operation of hardware components. Instead of storing keys in dedicated secure storage, the system embeds key material within the operational characteristics (timing, power consumption, signal propagation) of standard hardware components, making extraction difficult without disrupting component function.
Solution Approach 2:
The patent introduces measurement and analysis techniques (such as time-domain reflectometry, power analysis, or timing analysis) as intermediaries between the hardware component and the key extraction process. These intermediary measurement methods allow the system to derive key material from operational characteristics without directly accessing traditional key storage locations, adding a layer of complexity to reverse engineering attempts.
2Ease of manufacture
If key information is concealed in standard hardware components, then manufacturing cost is reduced, but detecting and measuring the key information becomes more difficult
Solution Approach 1:
The patent replaces traditional mechanical or electronic key storage mechanisms with measurement-based key derivation. Instead of physically storing key bits in memory cells, the system uses measurement of hardware operational characteristics (timing, power consumption, signal properties) to derive key material, substituting direct storage with indirect measurement.
Solution Approach 2:
The patent changes the fundamental parameter used for key storage from static memory contents to dynamic operational characteristics. Keys are derived from parameters such as signal propagation time, power consumption patterns, or timing characteristics that naturally vary with hardware manufacturing tolerances, making each device unique while using standard components.
3Reliability
If hardware measurement techniques are used for key generation, then unauthorized access is restricted, but system complexity increases
Solution Approach 1:
The patent makes standard hardware components serve multiple functions: their primary functional role plus key generation/storage. For example, a standard logic gate or transmission line not only performs its logical or signal transmission function but also contributes to key material generation through its measurement characteristics, eliminating the need for separate key storage hardware.
Solution Approach 2:
The system uses the hardware components' own operational characteristics to generate their own key material. Each component's natural variations in timing, power consumption, or signal properties serve as the source of key entropy, making the hardware self-describing in terms of its security credentials without requiring external key provisioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly restricts unauthorized access by ensuring that only authorized systems can generate and use the correct keys, maintaining system security and integrity even in harsh or unpredictable environments.
Implementation Method 1
a transmitter that transmits, at a pulse transmission location, at least one pulse along the at least one signal conductor; a detector that determines transmission characteristics of the at least one signal conductor by detecting, at a detection location, a return signal propagated along the conductor as a result of the pulse transmission
Data Source
AI summary
A system and method of recovering encoded information contained in a device by storing and retrieving at least part of the necessary decoding data by setting and measuring the physical characteristics of the device. Storage and recovery options include, but are not limited to, measurement of electronic or optical characteristics of electrically or optically conductive portions of the device using a range of measurement techniques that include, but are not limited to, time-domain reflectometry.