Partitioning

What is partitioning?

Partitioning is the process of separating an individual’s browsing data from one website to another, as a countermeasure against the trackers embedded in third-party ads. These trackers will otherwise attempt to identify individuals and track their activity across websites.

How online tracking works

As you browse the Web, you may encounter third-party ads with trackers built into their programming. Web trackers will try to store data about you and your online activity on your device, and then collect that data when you’ve finished browsing. The data these trackers collect can be used to identify you the next time you’re browsing, with the goal of showing you targeted ads while adding more information to your profile.

Web trackers use different tactics to collect your data and build a profile of you. One tactic is called fingerprinting, where a tracker attempts to identify you based on your device hardware and the specific characteristics of the software on that device. Another tactic is third-party storage, which involves storing and linking unique identifiers for users across sites other than the one you intend to visit. Cookies are one kind of third-party storage mechanism that are often used to link users across websites but there are others such as local storage. A browser can just disable third-party storage, but this often breaks websites.

Browser partitioning attempts to block third-party storage tracking while still maintaining website functionality.

Cookie partitioning

Blocking third-party ads and trackers from storing cookies and other browser-state information can go a long way toward improving an individual’s online privacy. Unfortunately, blocking this state will often break a website, rendering it unviewable. Some browsers, including Brave, use browser partitioning to solve this problem.

Brave partitions cookies and other state data into separate areas, one per website, effectively quarantining this data from other websites. When you close the website with the tracker, the data in these partitions is erased. If you have more than one website open with the same tracker embedded, each cookie the tracker creates is placed in a separate partition.

A tracker counts on being able to not only collect their cookie data, but all the other data stored with it. Harvesting all this extra data is how a tracker can build a robust profile of you. By partitioning the tracker data along with the rest of the browsing data (especially the necessary and benign data needed for a seamless browsing experience), Brave minimizes the amount a tracker can learn about you and your activity. Nothing is learned about cross-site activity.

Brave actually goes a step further in its protections and deletes all partitions when the site is closed, thus also preventing the site itself from learning about repeat visits or building a long-term profile on the user.

Learn more about how Brave handles third-party storage using a process called Ephemeral third-party site storage.

Network state partitioning

In response to the rise in browsers that employ cookie partitioning, third-party ad servers have developed a more sophisticated tracking technique that taps into the network state of the browsing session. The network state is a collection of dozens of caches and connection data related to your browsing session—things like the same image being loaded across different websites, for instance. A sophisticated tracker can use this network data to identify users across different websites. 

Following the same approach used to partition cookies, Brave once again leads the way by partitioning and deleting network state data that trackers attempt to collect. The result is less data about both you (your fingerprint) and your activity (your digital footprint) in the hands of data brokers.

Learn more about how Brave uses network-state partitioning to improve privacy.