Secure Distance Measurement via Sub-period Pulse Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secure distance measurement systems are vulnerable to early detect late commit attacks, where attackers can manipulate the time of flight by anticipating the arrival of pulses, and they require longer inter symbol distances to avoid inter symbol interference, leading to slower verification times.
Innovation Solution
Defining sub-periods for pulse detection and decoding, using pulse modulation with two or more states, and correcting inter pulse interference based on channel impulse response to prevent attackers from manipulating the time of flight, while allowing shorter inter pulse distances for faster verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If longer inter symbol distances are used to avoid inter symbol interference, then measurement precision is improved, but verification time increases (productivity deteriorates)
Solution Approach 1:
The patent segments the pulse transmission into multiple sub-periods, where each sub-period corresponds to a specific time interval for receiving pulse components. By dividing the reception window into sub-periods, the system can selectively process only the relevant portions of the signal, enabling faster verification while maintaining precision through targeted measurement of specific sub-periods rather than requiring longer overall inter-symbol distances.
2Measurement precision
If the time period of received pulse is extended due to multipath transmission or redundancy, then measurement precision is improved, but vulnerability to early detect late commit attacks increases
Solution Approach 1:
The patent applies preliminary action by pre-defining sub-periods based on the expected channel impulse response before the actual measurement takes place. These pre-calculated sub-periods are used to structure the reception and processing of pulse signals, allowing the system to anticipate and filter out malicious extensions of pulse time periods while maintaining accurate measurement of the legitimate first path signal.
Solution Approach 2:
The patent applies local quality by focusing measurement and processing resources specifically on the sub-periods corresponding to the first path of the channel impulse response. Instead of uniformly processing the entire extended pulse period, the system selectively analyzes only the relevant sub-periods, thereby maintaining measurement precision for the legitimate signal while ignoring or filtering out extensions that could be exploited by attackers.
3Productivity
If equalizer is used to remove inter symbol interference, then productivity is improved, but reliability deteriorates due to potential misuse for early detect late commit attacks
Solution Approach 1:
Rather than using a full equalizer that processes the entire signal, the patent segments the signal processing into sub-period-specific operations. Each sub-period is processed independently with tailored processing parameters, which prevents the equalizer from creating vulnerabilities while maintaining processing efficiency. This segmented approach achieves productivity improvement without the reliability risks associated with conventional equalization.
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 prevents early detect late commit attacks and ensures reliable, fast, and secure distance measurement by giving weight to specific sub-periods of the receiving signal for decoding, thereby enhancing the security and speed of verification.
Implementation Method 1
the receiving device detects the transmitted message in the receiving signal and decodes the verifying bit sequence from the receiving signal
Implementation Method 2
a bit of the transmission message is transmitted in the transmission signal by a pulse with a pulse modulation parameter with two pulse states
Implementation Method 3
correcting inter pulse interference based on channel impulse response to prevent attackers from manipulating the time of flight
Data Source
AI summary
Device for secure distance measurement being a prover (P) or a verifier (V) comprising: a receiver (R3) configured to receive a receiving signal (RS) with a transmitted message (M) encoded therein, wherein the transmitted message (M) contains a verifying bit sequence (VBS), wherein a bit of the transmission message (M) is transmitted in the transmission signal (TS) by a pulse with a pulse modulation parameter with two pulse states, and a decoder (R2) configured to decode the verifying bit sequence (VBS) from the transmitted message (M) encoded in the receiving signal (RS). The decoder (R2) is based on a transmission format of the transmitted message (M) and based on the transmitted message (M) detected in the receiving signal (RS) defines sub-periods (4) in the receiving signal (RS) in which the first path (F1, F2) of the pulses (S1, S2) of the bits of the verifying bit sequence (VBS) of the transmitted message (M) are expected in the receiving signal (RS); and the decoder (R2) decodes a pulse state of a pulse (S1, S2) of a bit of the verifying bit sequence (VBS) based on the receiving signal (RS) received during one of the defined sub-periods (4) belonging to the pulse (S1, S2) to be decoded.