The following issue, owned by Brian Behlendorf, is on the HTTP/1.1
issues list:

* BB USERTRACKING Privacy from user tracking based on accept 
  ([holtman 6.2, 6.3])

I mailed Brian for status about this on April 7, but he has not
responded so far.  I'll take over the issue until I hear from Brian.
Below is proposed text for the 1.1 draft, adapted from [holtman 6.2,

I'd like to close this issue in a few days: I do not think it is very
controversial.  If you have any comments on, or improvements for, the
text below, please send them in private e-mail. I'll summarize on the



   [## Note: the text below could be in a separate section, but could
   also be added to the existing section 14.7 on `Privacy issues
   connected to Accept headers'.##]

14. Security Considerations

14.x User tracking based on accept headers

   Elaborate user-customized accept header fields sent in every
   request, in particular if these include quality values, can be used
   by servers as relatively reliable and long-lived user identifiers.
   Such user identifiers would allow content providers to do
   click-trail tracking, and would allow collaborating content
   providers to match cross-server click-trails or form submissions of
   individual users.  Note that for many users not behind a proxy, the
   network address of the host running the user agent will also serve
   as a long-lived user identifier.  In environments where proxies are
   used to enhance privacy, user agents should be conservative in
   offering accept header configuration options to end users.  As an
   extreme privacy measure, proxies could filter the accept headers in
   relayed requests.  General purpose user agents which provide a high
   degree of header configurability should warn users about the loss
   of privacy which can be involved.

[End of text]

Received on Saturday, 13 April 1996 13:48:02 UTC