“One afternoon late last month, security researcher Hristo Bojinov placed his Galaxy Nexus phone face up on the table in a cramped Palo Alto conference room. Then he flipped it over and waited another beat.
And that was it. In a matter of seconds, the device had given up its “fingerprints.”
Code running on the website in the device’s mobile browser measured the tiniest defects in the device’s accelerometer — the sensor that detects movement — producing a unique set of numbers that advertisers could exploit to identify and track most smartphones.“