Description
Bluetooth Channel Sounding (BCS) represents a significant advancement in secure,
high-accuracy distance measurement for proximity-based applications. This thesis
evaluates the security mechanisms of BCS, focusing on its usage of Phase-Based Ranging
(PBR) and Round-Trip-Time (RTT) to mitigate sophisticated attacks such as relay
attacks and Man-in-the-Middle attacks. Through structured analysis, the protocol’s
cryptographic features, including Deterministic Random Bit Generator (DRBG) randomization,
Normalized Attack Detector Metric (NADM), and physical layer interface
hardening, are shown to provide robust defenses when fully implemented. However,
the specification’s flexibility introduces critical implementation-dependent vulnerabilities.
Key findings reveal that optional security features and non-enforcement of
hardened PHYs leave room for exploitable configurations. Testing commercial development
kits from Silicon Laboratories and Nordic Semiconductor further highlights
gaps in compliance, such as omitted PBR/RTT cross-validation and NADM reporting.
While BCS offers a powerful toolkit for secure ranging, its efficacy ultimately hinges on
rigorous adherence to security best practices.
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