RFID Tag Timing Circuit for Relay Attack Location Certification
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Solution Overview
Problem
RFID systems are vulnerable to relay attacks, which fake the close proximity of authorized users, and there is a need for a secure and efficient method to certify the location of RFID tags.
Innovation Solution
A low-energy, compact, and cost-effective circuit solution for RFID tags that uses a synchronization impulse and a sequence of bits to evaluate the signal travel time between the RFID reader and tag, employing RC, LC circuits or digital integrated elements, and XOR devices to ensure secure location certification, resistant to relay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional RFID systems are used, then communication between reader and tag is simple and inexpensive, but the system is vulnerable to relay attacks and lacks location certification security
Solution Approach 1:
The patent implements location certification by sending a synchronization impulse before the actual data transmission. This preliminary action establishes a reference time point that enables the reader to calculate signal travel time and verify the tag's physical location, preventing relay attacks before they can occur
Solution Approach 2:
The patent replaces complex cryptographic authentication mechanisms with a physics-based solution using signal travel time measurement. By measuring the time difference between sending the synchronization impulse and receiving the tag's response, the system determines physical proximity without requiring complex security circuits
2Reliability
If location certification is implemented using existing methods, then security against relay attacks is improved, but energy consumption and circuit size increase
Solution Approach 1:
The RFID tag uses the incoming signal from the reader to generate its response without requiring separate power amplification circuits. The tag's circuitry is designed to detect and respond to the synchronization impulse and data signals passively, minimizing energy consumption while still enabling location certification
Solution Approach 2:
The system recovers location information from the timing characteristics of the tag's natural response to the synchronization impulse. Instead of requiring the tag to send additional active signals that would consume energy, the reader measures the time delay of the tag's reflected or retransmitted signal, which contains the location information without requiring extra energy from the tag
3Measurement precision
If signal travel time measurement is implemented, then location accuracy is improved, but the system becomes more complex and expensive
Solution Approach 1:
The synchronization impulse serves multiple functions: it synchronizes the tag's response, provides a time reference for location calculation, and enables the reader to measure signal travel time. This multi-functionality eliminates the need for separate circuits for each function, maintaining manufacturing simplicity while achieving precise location measurement
Solution Approach 2:
The patent measures location by detecting changes in signal timing parameters rather than requiring complex spatial measurement circuits. By measuring the time delay between transmitting the synchronization impulse and receiving the tag's response, the system calculates distance based on the speed of light, achieving high precision with simple timing circuits that are easy to manufacture
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
The solution provides fast, simple, and secure location certification, resistant to relay attacks, allowing for accurate evaluation of the RFID tag's range and ensuring correct encryption, thus preventing unauthorized access.
Implementation Method 1
RFID (Radio Frequency Identification) systems are lacking security - today they are not secure against relay attacks. According to RFID methods, close proximity is needed for physical reasons to make the system work.
Implementation Method 2
Document US 2012/249296 describes a RFID system using the limitation of light speed to certify a location.
Implementation Method 3
the input transmission line, said main line and said different transmission lines act as signal delay elements
Implementation Method 4
said input transmission line, said main line and said different transmission lines comprise RC, LC circuits or digital integrated elements
Data Source
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Figure 4
AI summary
An RFID tag for a product, the RFID tag comprises: a receiver configured to receive an input signal from a RFID reading device, comprising a synchronization impulse and a sequence of bits, and to dispatch the input signal to a tag substrate comprising an input transmission line and a transmission line array allowing the input signal to be split from a main line into different transmission lines each comprising a connector or an absorber, an OR device configured to add up signals to a certificate signal that represents the bits from a certificate in a time sequence, the signals being yielded from the synchronization impulse having travelled through the different transmission lines, a XOR device processing the input signal from the input transmission line and the certificate signal from the transmission line array to yield an output signal, a transmitter configured to transmit the output signal to the RFID reading device.