Transponder Relay Attack Detection via Energy-Dependent Processing Time
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Solution Overview
Problem
Transponder units are vulnerable to relay attacks, where an attacker intercepts and relays communication between a transponder unit and a reading device, allowing unauthorized transactions, and existing methods are inadequate for effective detection and defense.
Innovation Solution
A method involving a reading device that prompts a transponder unit to perform a calculation twice, once with energy within its saturation range and once with reduced energy, to evaluate processing times and detect significant differences, indicating a potential relay attack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the transponder unit operates with reduced energy to extend battery life or function in weak fields, then energy efficiency is improved, but processing time increases
Solution Approach 1:
The patent measures processing time as a function of energy availability by varying the read field strength (energy parameter) and observing changes in processing time. This parameter-based approach allows detection of relay attacks through the relationship between energy levels and processing time characteristics.
2Reliability
If relay attack detection methods are implemented, then security is improved, but device complexity increases
Solution Approach 1:
The transponder unit performs self-identification by providing its unique identifier in response to a request, and the reader detects relay attacks by analyzing the processing time characteristics of this self-service response. The system uses the transponder's own operational characteristics for detection without requiring additional external verification infrastructure.
Solution Approach 2:
The system measures the feedback loop time between requesting the transponder to perform a calculation and receiving the result. This feedback time measurement provides information about the transponder's energy availability and helps detect relay attacks through abnormal time characteristics.
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
Effectively detects relay attacks by identifying discrepancies in processing times, preventing unauthorized transactions and providing a means for testing and quality control of transponder units.
Implementation Method 1
Typically, such transponder units are powered by a read field generated by the reader
Data Source
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AI summary
In a method between a transponder unit (20) and a reading device (10), the reading device prompts (S2) the transponder unit to carry out a predetermined calculation. The predetermined calculation is carried out (S3) in the transponder unit, wherein the transponder unit makes energy available according to a first value in order to carry out the predetermined calculation. A first processing time (t1) is determined (T2, T5, T6), which the transponder unit has required in order to carry out the predetermined calculation. The steps of carrying out (S7) the predetermined calculation and of determining a processing time, the second processing time (t2), are repeated, wherein the transponder unit makes energy available according to a second value that is different from the first value, in order to repeat the carrying out of the predetermined calculation. Finally, the first and second processing times are evaluated (S9).