Given all of the personal information that we have stored on our mobile devices, Android phones could potentially serve as treasure troves of private data for those who wish to learn everything about you for profit. It’s not only Google who is trying to learn everything about you. Rather, many other vendors that also collect as much personal data as possible. One of the main personal identifiers is the MAC addresses of the communication devices on your phone. Another’s your IMEI or ESN. This data can be and probably will be used to make as much money from you as possible, and you can find out more about that in this related article.
One method to prevent breach of privacy is constantly switching off your data connections when not in use (or manually changing your WiFi adapter’s MAC address). However, this is quite tedious and time consuming. Thankfully, there is a better way with XDA Senior Recognized Developer Chainfire‘s new application Pry-Fi. This application prevents your phone from sharing sensitive information about your saved networks without forgetting them, so your device will still connect to your preferred networks automatically. Normally, your device constantly broadcasts its MAC address even when the WiFi is off, due to the “scanning always visible” option. With Pry-Fi, your MAC address will be pseudo-randomized and will slowly poison the tracking database with useless information. And while connected, your MAC address will not be used again per session, making tracking nearly useless. Pry-Fi can also create a “war” and let your device appear as dozens of devices.
Pry-Fi doesn’t work with all devices, as some OEMs have implemented their own security policies. It should work fine with a handful of devices including the Google Nexus 5, Samsung Galaxy S4, Samsung Galaxy Note 3, and HTC One. It might work on other devices, but your mileage may vary. It requires SuperSU to work fully, and there is a great chance that Pry-Fi won’t work with other superuser apps. The list of issues contains a few quirks, but the pros still far outnumber the cons.
More information about the project can be found in the original thread.