Description
MAC address randomisation is the OS-level countermeasure that rotates the MAC address used in Wi-Fi probe requests so that passive sniffers cannot link successive frames to the same device. iOS, Android, and Windows have all rolled it out in slightly different forms. From the sensing side it is the central obstacle to wifi-probe-request-sensing working as a long-term tracking primitive and is the constant context for any privacy-aware CSI / probe-request crowd-analytics pipeline.
When it's used
- Privacy threat model in crowd-analytics deployments
- De-randomisation feature engineering (IE fingerprints, sequence numbers)
- Justification for moving from probe sniffing to CSI-based occupancy
Limitations
- Implementations leak side-channels (sequence numbers, vendor IEs)
- Vendor inconsistency complicates sensing pipelines
- Counter-counter-measures change the threat model regularly