Valkyrie

Wireless communications integrated in connected devices can expose their users to tracking via the exposure of link layer identifiers (e.g. MAC addresses). To counter this threat, it has been proposed to replace those permanent identifiers with periodically changing random pseudonyms [17]. This practice, called address randomization has been progressively adopted by vendors [28, 36] and has even made its way to wireless standards [1, 35]. However, an effective implementation of address randomization requires more than periodically rotating the link layer identifier. Indeed, several works [8, 11, 12, 16, 27, 28, 36] identified issues with address randomization implementation, where in-frames counters and identifiers can undermine the anti-tracking measure.