Evercookie Demo

This Page tries to remember how often you visited it. You can try various Tricks to reset the Counter. This is normally not done but this Page will inform you about any problems it finds when you try to avoid its Tracking.

We believe you are here for the first time. Reload this Page to see if we can track you.
Current Time 2021-02-28 16:44:40 CET
Number of Visits 1
Current ETag Value wKzjWT081aeAJzHweBnF9Q==:RHhEjh9OqgVSxc6c:PA==
JavaScript enabled but not working (usually blocked by an Extension)disabled
Cookies unknown

To reset the counter, you have to clear your browser cache and delete cookies at the same time. Just disabling JavaScript and/or Cookies will not help, just clearing the cache alone won't either. Most Browsers offer an uncached refresh with CTRL+F5 if you want to try.

If Cookies are enabled (see above) you will find that the Counter will still persist and increase with every reload. You have to disable or delete Cookies and clear the Cache before performing any Type of Request again to reset the Counter.

Click here to clear all Data We can't detect if this works or not as of now. You have to try.

This method is used by Ad Agencies to track People and is resistant to clearing the Cookies. It abuses the ETag Header, which is normally used to handle caching of Resources. The Cookie is used as a Backup in case the ETag value is not sent by the client (cache deleted).

This works because a Server can simulate that the Value sent back from the Browser has expired. The Server then updates the Value and sends new Content.

The information below is from the Perspective of the Ad

Advantages

This Technology brings multiple Advantages over a traditional Cookie only approach

Hard to remove

ETag is resistant against Removal or Blocking of Cookies.

No JS or Cookies

ETag is a feature of the HTTP Protocol itself. Neither JavaScript nor Cookies are required for it to work

Universal

All Browsers implement the ETag Feature

Hidden

The ETag Cookie is automatically handled by Server and Browser. Users will not notice it

Resource type independent

ETags work with any Type of Resource as long as a Request is involved. This means a static Request to /some-ad can still deliver different Content each time it's requested.

Free Format

There are almost no Format Requirements for the Value of the ETag

Uneditable

No Browser offers Users a Way to edit ETags, which means the Value is faked out less likely

User Bound

The Tag is bound to a user rather than an IP address

Disadvantages

This Technology also comes with a few Disadvantages

Cache Cleaning

If the User or the Browser cleans up the Cache, the Tag can get lost. Browsers clean old Items from the Cache to keep the Size small and the Content relevant. Depending on how much new Content is cached, this can happen sooner or later. This Issue can sometimes be mitigated by combining the Header with a Cookie and using the Cookie as a Backup in case the Header is missing.

Identical URLs

The URL to deliver a certain Tag must always be the same. It doesn't has to deliver the same Content Type at all. Switching between Video and Images is possible if the Page that includes the Ad knows beforehand what Type is delivered.

Length Restriction

The Value of the ETag has to be rather short, for example a User Id. The Length of this sites ETag is 46 bytes. In our case, it's an encrypted view counter.

Protection

There is currently no real Protection against this Type of Tracking. Users can sort of protect themselves by instructing their Browsers to delete all Browser Data on every Exit. This would cause Ads to see Users as new after every Browser Restart. A Downside for the User is that all Sessions and Site Settings are also lost. Browsers could be trained to ignore ETag if a Resource changes too often.