Key Derivation for UWB Ranging in Keyless Entry
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Solution Overview
Problem
Modern keyless entry systems in vehicles face security challenges, particularly in ultra-wide band (UWB) RF ranging systems, where attacks like relay and preamble injection can manipulate distance measurements, and existing solutions have high overhead and do not adequately protect the confidentiality, integrity, and authenticity of data frames, especially in limited RF budgets.
Innovation Solution
A key derivation scheme is introduced for UWB RF communication that uses Type 1 and Type 2 data frames, employing ECB or CBC encryption for Type 1 frames and authenticated encryption for Type 2 frames, with a Generic Scrambled Timestamp Sequence (GSTS) index to ensure confidentiality, integrity, and authenticity, minimizing data transmission while protecting against attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encryption schemes are used for data frame transmission in UWB ranging systems, then security against relay and preamble injection attacks is improved, but data overhead increases and RF budget is consumed
Solution Approach 1:
The patent extracts and removes unnecessary encryption overhead from data frame transmission. Instead of encrypting entire data frames, the invention applies encryption only to critical security elements (preamble and specific fields), thereby maintaining security while significantly reducing data overhead and preserving RF budget for ranging measurements
Solution Approach 2:
The patent applies different encryption strategies to different parts of the data frame based on their security requirements. The preamble receives full encryption protection, while other fields use selective encryption or authentication mechanisms, optimizing the balance between security and efficiency for each specific component
2Reliability
If full encryption of data frames is applied to protect confidentiality and integrity, then security is improved, but transmission efficiency decreases and energy consumption increases
Solution Approach 1:
The patent applies partial encryption action by encrypting only the essential security-critical portions of data frames (particularly the preamble containing synchronization and security information) rather than the entire frame. This partial approach maintains data integrity and confidentiality for critical elements while preserving transmission efficiency and reducing energy consumption
3Reliability
If authentication mechanisms are added to verify data frame authenticity, then protection against attacks is improved, but device complexity increases
Solution Approach 1:
The patent merges authentication functionality with the existing encryption framework by integrating authentication tags and verification mechanisms directly into the encrypted data frame structure. This consolidation allows authenticity verification to be performed as part of the normal decryption process, reducing the need for separate authentication hardware or protocols and thereby managing device complexity
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 scheme effectively reduces data overhead, enhances security by protecting user privacy and data integrity, and prevents attacks like relay and preamble injection, while maintaining efficient energy use in UWB RF communication.
Implementation Method 1
An UWB RF ranging system typically employs the Time-of-Flight principle to determine the distance between the tag and the structure to be opened or markers on the structure. Usually, a transceiver's transmitter sends out a waveform, commonly a chirp or a pulse, which is either reflected by an object or retransmitted by a second transceiver. Based on the amount of time it takes for the reflection or retransmission to reach the originating transceiver's receiver, the distance between the objects can be calculated.
Data Source
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AI summary
Disclosed are methods and devices for deriving keys for coding the contents of data frames, which are to be transmitted in a keyless entry system during an ultra-wide band ranging session between a transceiver device coupled to a base structure to be opened and closed and/or to be locked and unlocked, and a mobile transceiver device associated with the structure-coupled transceiver device.