Seattle Surveillance Technologies Up for Public Review

Re:Seattle Surveillance Technologies Up for Public Review by rfoo on Wednesday February 06, 2019 @04:32PM (#19100222)

> generates a one-way hash code from the detected device’s MAC address (using a SHA-256 algorithm)

This does not sound truly "no way to reverse" if they are using plain or some simple variants of SHA-256. There are only up to 2^48 possible MAC addresses (way less in practice), which is a very realistic number for rainbow tables.

That said, this might be less relevant quickly as more and more devices are going to use randomized MAC addresses for probing Wi-Fi networks.

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Re:Seattle Surveillance Technologies Up for Public Review by loeg on Wednesday February 06, 2019 @05:03PM (#19100553)

Also, (typical) MAC addresses are not random; the upper 24 bits are constrained to a given smaller set of manufacturer codes, so you can reduce the search space considerably.

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Re:Seattle Surveillance Technologies Up for Public Review by Zelizz on Wednesday February 06, 2019 @07:57PM (#19101934)

Unless they purposefully produced hash collisions by truncating the hash, they've just traded one unique identifier for another one. The information they throw away is not very hard to recreate, you just need to discover an individual person again (provided that the MAC hasn't changed), hash it, and now you've got the hash->MAC mapping for that individual, and you can look at their location history.

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