I wonder if there's a way using javascript/dom events to tell whether an image
is loaded from cache. Then sending data async would be trivial...
On March 29, 2014 3:19:13 PM EDT, Claudio Fontana <[email protected]>
wrote:
>something involving canvas maybe? That info can be queried by the
>server
>afaik
>
>On Saturday, March 29, 2014, <[email protected]> wrote:
>
>> Are you sure about that ? My source was an academic research a guy
>made,
>> in Germany.
>>
>> On 2014-03-29 20:32, Narcis Garcia wrote:
>>
>>> As I know, cached files or their content aren't uploaded back to
>>> webserver.
>>>
>>>
>>> Al 29/03/14 15:24, En/na [email protected] ha escrit:
>>>
>>>> I would like to report some additional findings:
>>>>
>>>> One way to track a user is to use graphic files as a substitute for
>>>> cookies. An image is created on a server with an identification
>number
>>>> encoded as color information. This image will be saved on a user's
>>>> computer in the browser cache. When this user visits the website
>again,
>>>> the locally stored image file will be opened and analyzed. The
>stored
>>>> color information will be sent back to the server to make tracking
>>>> possible. Since graphics are stored in a different location than
>>>> cookies, they aren't deleted when you clear your cookies. Other
>>>> techniques include HTTP E-Tags, Flash cookies or web storage.
>>>>
>>>> --
>>>> http://gnuzilla.gnu.org
>>>>
>>>
>>> --
>>> http://gnuzilla.gnu.org
>>>
>>
>> --
>> http://gnuzilla.gnu.org
>>
>
>
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>Claudio Fontana
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>email: [email protected]
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>tel mobile (work): +49 15253060158
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