A study called “SensorID: Sensor Calibration Fingerprinting for Smartphones” examined sensor fingerprinting techniques against smartphones. It found that Micro Electro Mechanical Systems (MEMS) are inaccurate in small ways that make them unique. But Apple thwarted this technique in iOS 12.2 and used the researchers’ suggestion to add random noise to the analog-to-digital converter output and removing default access to motion sensors in Safari.
We demonstrate that our approach is very likely to produce globally unique fingerprints for iOS devices, with an estimated 67 bits of entropy in the fingerprint for iPhone 6S devices. In addition, we find that the accelerometer of Google Pixel 2 and Pixel 3 devices can also be fingerprinted by our approach.
Check It Out: Apple Thwarts Sensor Fingerprinting With iOS 12.2
Of course a router has to know the MAC address. It’d do a rather poor job of routing if it didn’t. Same if true of all the Ethernet switches you might have too.
But It doesn’t provide that address to to apps on the iPhone. And THAT’S what’s important here. So an app on your iPhone can’t “fingerprint” to get a unique identifier to tag you with.
“Apple removed access to MAC addresses”
Really many iOS apps don’t have access to Apple devices MAC addresses, interesting is that my Huawei WiFi router have all Apple MAC Addresses…