How to track a website user without asking permission

By | August 5, 2015

HTML5 seems to have introduced a new way to track innocuous website visitors on mobile devices such as laptops, mobile phones, and tablets – no cookies required! The level of detail provided includes 16 decimal digits – a double – on your battery health, which allows a website to get a pretty accurate and unique device profile. That means a way to track you!

There's no magic potion against this yet, other than to use Tor (which is a bit slower and doesn't support the battery life API for that reason). Then again, if you have no problem with cookies, would you really care?

Privacy analysis shows battery status API as tracking tool

3 thoughts on “How to track a website user without asking permission

  1. Sophie Wrobel

    +T. Pascal Agree, there really isn't. I'd guess that the programmer saw that the specification just required sending the number onwards, and didn't think of why he might want to send a round(number) instead of simply the number.

    Also, there's no reason why the browser settings don't contain a 'hide send my device status' setting somewhere – the same way I can turn off sending my location data to sites who want to use it.

  2. T. Pascal

    There's no reason a device needs to return 16 decimal places. They should truncate to two at the client side.


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