A little-known feature of HTML5 called Battery Status enables the sites in the Network to know how much power is left in the battery of a laptop or smartphone user. Experts in the field of information security from France and Belgium warn that this information can be used to track human activity.
Currently the data transfer status of the battery support browsers Firefox, Opera and Chrome. This functionality was introduced in 2012 to help websites to extend the battery life of gadgets. Wonder what a resource the Internet will be able to recognize when a visitor is on low battery, and switch in a low power mode by turning off energy-consuming functions.
The W3C specification relieve websites from having to ask the user permission to read battery life, as “this information has a minimal effect on privacy. However, the results of the study suggest otherwise.
Experts note that the sites receive information on the calculation time in seconds and the battery level, expressed in percent. These two numbers, taken together, create 14 million combinations, and is refreshed every 30 seconds. This means that for half minute information about the status of the battery can be used for identification of a person, regardless of privacy settings. In other words, these details create a unique unique ID of the user’s device.
For a short period of time, the site may determine one and the same person, even if at first he went after private browsing or VPN service, and then in normal mode. Battery Status can also “learn” the person after he removes the cookies. After this API will help to restore deleted cookies on the user side.
Moreover, on some platforms, as discovered by the researchers, it is possible, having sent enough requests, calculate the maximum capacity of the battery, which will allow long-term tracking of user activity on the Internet.
