# The Privacy Risk Posed by Unique Identifiers Assigned to Android and iOS Devices
In our highly interconnected society, smartphones have become a crucial component of our everyday routines. Whether it’s checking emails or exploring new routes, we depend on these devices for a variety of activities. However, beneath this convenience lies a considerable privacy concern that many users may not recognize: the unique IDs assigned to Android and iOS devices. These identifiers, intended to assist advertisers and developers in tracking user activities, can be misused by organizations to observe your movements and actions, often without your awareness or consent.
## The Influence of Companies Such as Babel Street and Location X
You might not be familiar with companies like Babel Street or their service, Location X, yet they probably possess more information about you than you think. Babel Street, located in Reston, Virginia, operates Location X, a service capable of monitoring the whereabouts of hundreds of millions of mobile devices for extended durations. While Babel Street asserts that access is limited to governmental law enforcement and contractors, the truth is that this information can be accessed by others under specific conditions.
For instance, an employee from a firm that aids individuals in removing their data from information broker databases managed to obtain a two-week free trial of Location X. By merely mentioning that they were considering future work with the government, they gained entry to a wealth of location data.
### The Functioning of Location X
Location X enables users to draw a perimeter—whether a state border, a city block, or even a specific structure—and obtain a historical record of Internet-connected devices that have traversed those boundaries. This information can disclose sensitive aspects of individuals’ movements and routines.
In one scenario, data from Location X indicated almost 100,000 occurrences involving the phone of a New Jersey police officer who had been subjected to a doxing harassment. The data depicted a comprehensive overview of the officer’s movements over multiple months, including visits to her residence. Although there’s no proof that those targeting the officer utilized Location X, the platform could have been easily leveraged to track her phone and home location.
## The Impact of Mobile Advertising Data
The technology that facilitates this degree of surveillance is embedded in the very operating systems we utilize each day—Android and iOS. Both systems allocate unique identifiers to devices, accessible by applications that possess location permissions. Android’s “Ad ID” is open to any app with location access, while iOS employs an “Identifier for Advertisers” (IDFA), which is more restricted yet still reachable by apps that seek permission.
Applications that gather location data often sell it to consumer data brokers, who then provide it to third parties, including companies like Babel Street. This data can also be acquired through the web advertising ecosystem. When a user visits an ad-supported website, the advertising network holds a real-time auction to deliver a personalized advertisement. A crucial element in determining the advertisement’s price is the location of the device accessing the site.
### Real-World Consequences
The ramifications of this data collection are extensive. In one particular instance, a journalist from 404 Media utilized Location X to focus on the parking lot of an abortion clinic in Florida. The reporter noted over 700 red dots, each symbolizing a phone that had recently visited the clinic. By selecting one device, the journalist was capable of tracing its journey from a home in Alabama, through various stops, and ultimately to the clinic. The data indicated that the individual carrying the phone had only visited the clinic once, but the depth of detail was concerning.
This method of tracking can lead to severe repercussions, particularly in sensitive scenarios like visits to healthcare facilities, protests, or other confidential activities. The ability to follow someone’s movements over time presents a substantial risk to personal privacy and safety.
## How to Safeguard Your Privacy
While the outlook may appear grim, there are measures you can adopt to protect your privacy and reduce the volume of data collected about you.
### 1. Review Application Permissions
The initial step is to assess which applications have access to your location. On Android, you can accomplish this by going to **Settings > Location > App location permissions**. For iOS, navigate to **Settings > Privacy & Security > Location Services**. Both operating systems allow you to identify which applications have location access and whether they can access it continuously, only during use, or never.
For the majority of users, it’s unnecessary for applications to have ongoing access to precise location information. For instance, apps like mapping or transit services may require accurate location data, but social media or gaming applications likely do not. You can also opt to provide applications with only approximate location data, which is less specific but still useful for many purposes.
### 2. Remove Your Advertising ID
On Android, you can further take measures to limit tracking by deleting your advertising ID. This can be achieved by going to **Settings > Security & Privacy > Ads** and selecting “Delete advertising ID.” While Google offers
