Cover your tracks
The EFF's test: do your blockers work, and how rare are you?
Cover Your Tracks loads simulated trackers to see which ones your browser blocks, then fingerprints you to measure how identifiable you remain even when they are blocked. It is the shortest honest answer to whether a privacy extension is doing anything.
What it checks
- Blocking of tracking ads and of invisible trackers
- Whether blocked trackers can still be read through cookies
- Fingerprint uniqueness, in bits of identifying information
- Which single attribute contributes the most bits
How to read the result
Bits of entropy are the number to watch: each extra bit halves the crowd you could be hiding in. Blocking trackers and being rare are separate results and often disagree.
What it does not prove
Randomising an attribute so it looks different on every visit can raise your uniqueness instead of lowering it — this test will show you that, and a pass-or-fail tool will not.
These tools are run by their own operators, not by us. Opening one sends your IP address and browser details to that site.
