Pretty Good Phone Privacy Masks Your Android Device ID, Mobile Data Leave a comment

As marketers, data brokers, and tech giants endlessly expand their access to individuals’ data and movements across the web, tools like VPNs or cookie blockers can feel increasingly feeble and futile. Short of going totally off the grid forever, there are few options for the average person to meaningfully resist tracking online. Even after coming up with a technical solution last year for how phone carriers could stop automatically collecting users’ locations, researchers Barath Raghavan and Paul Schmitt knew it would be challenging to convince telecoms to implement the change. So they decided to be the carrier they wanted to see in the world.

The result is a new company, dubbed Invisv, that offers mobile data designed to separate users from specific identifiers so the company can’t access or track customers’ metadata, location information, or mobile browsing. Launching in beta today for Android, the company’s Pretty Good Phone Privacy or PGPP service will replace the mechanism carriers normally use to turn cell phone tower connection data into a trove of information about users’ movements. And it will also offer a Relay service that disassociates a user’s IP address from their web browsing.

“If you can decouple a user’s identity from the way they connect to a network, that’s a general-purpose hammer that can solve a lot of privacy problems,” says Raghavan, a professor at the University of Southern California. “Privacy should be the default and it’s not currently, so we’re working on that. There’s a growing appetite as people become more concerned about what their phone is leaking to telecoms and tech companies.”

PGPP’s ability to mask your phone’s identity from cell towers comes from a revelation about why cell towers collect the unique identifiers known as IMSI numbers, which can be tracked by both telecoms and other entities that deploy devices known as IMSI catchers, often called stringrays, which mimic a cell tower for surveillance purposes. Raghavan and Schmitt realized that at its core, the only reason carriers need to track IMSI numbers before allowing devices to connect to cell towers for service is so they can run billing checks and confirm that a given SIM card and device are paid up with their carrier. By acting as a carrier themselves, Invisv can implement their PGPP technology that simply generates a “yes” or “no” about whether a device should get service. 

On the PGPP “Mobile Pro” plan, which costs $90 per month, users get unlimited mobile data in the US and, at launch, unlimited international data in most European Union countries. Users also get 30 random IMSI number changes per month, and the changes can happen automatically (essentially one per day) or on demand whenever the customer wants them. The system is designed to be blinded so neither INVISV nor the cell towers you connect to know which IMSI is yours at any given time. There’s also a “Mobile Core” plan for $40 per month that offers eight IMSI number changes per month and 9 GB of high-speed data per month.

Both of these plans also include PGPP’s Relay service. Similar to Apple’s iCloud Private Relay, PGPP’s Relay is a method for blocking everyone, from your internet provider or carrier to the websites you visit, from knowing both who you are and what you’re looking at online at the same time. Such relays send your browsing data through two way stations that allow you to browse the web like normal while shielding your information from the world. When you navigate to a website, your IP address is visible to the first relay—in this case, Invisv—but the information about the page you’re trying to load is encrypted. Then the second relay generates and connects an alternate IP address to your request, at which point it is able to decrypt and view the website you’re trying to load. The content delivery network Fastly is working with Invisv to provide this second relay. Fastly is also one of the third-party providers for iCloud Private Relay.