MAC Address

Guide to Using MAC Address for People Counting

MAC Address stands for Media Access Control Address. This is an identification code assigned to network connected devices. It uniquely identifies every device on a network.

MAC addresses comprise six groups of two hexadecimal digits. In mobile phones, they can be used to identify people.

The addresses are "pseudonymised". This means that additional information is needed to connect the data to a person. However, pseudonymised data can still be used to single individuals out and combine their data from different records.

Mobile device manufacturers increasingly deploy MAC address randomisation to try to protect user privacy and the persistent hardware identifiers being tracked. However, there are many phones that do not effectively prevent tracking

Devices continually send out Probe Requests to scan for available access points. This has the side effect of announcing their presence and trackable identity information to every nearby eavesdropper.

Media Access Control (MAC) address randomization involves sending a random identifier in network transmissions in place of the fixed identifier, in an attempt to improve privacy.

More Information

Why you shouldn't use mobile phone signals to count people: Dutch city fined €600000

Three Years Later: A Study of MAC Address Randomization In Mobile Devices And When It Succeeds. July 2021 Proceedings on Privacy Enhancing Technologies 2021(3):164-181

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