[kakkksaknmdm]

This was used publicly in around 2016, stopped using around 2017 when research showed even better ways that cannot be spoofed: https://boingboing.net/2019/05/22/unique-device-fingerprints...

Ours was more advanced then this. As far as I've read the paper cited on the source above, they are like 30% of ours tech POC back in 2015.