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Re: Privacy and HTTP intermediaries

From: Ben Niven-Jenkins <ben@niven-jenkins.co.uk>
Date: Tue, 3 May 2011 23:44:17 +0100
Cc: Mark Nottingham <mnot@mnot.net>, httpbis mailing list <ietf-http-wg@w3.org>
Message-Id: <C5E48EDE-D3E4-428B-B19C-CF3B56C560E2@niven-jenkins.co.uk>
To: "Thomson, Martin" <Martin.Thomson@commscope.com>

On 3 May 2011, at 03:16, Thomson, Martin wrote:

> On 2011-05-03 at 11:47:45, Mark Nottingham wrote:
>> On 03/05/2011, at 11:10 AM, Thomson, Martin wrote:
>> 
>>> Does the value of the Cache-Control header have any bearing on whether 
>>> something is logged?
>> 
>> Nope.
>> 
>> I suppose you could read Cache-Control: no-store has having those 
>> semantics, but it doesn't in any implementation I'm aware of. Perhaps 
>> we need to clarify that.
> 
> With my privacy nut hat on, it would be nice if that could be added.

If what could be added? A clarification that no-store suddenly has an associated semantic that no implementation associates with it currently?

>  It's certainly consistent with the definition of no-store.
> 
> I'm not expecting the guidance to have any teeth, nor for it to have any impact on implementations, but there's a definite advantage to having text to that effect.
> 

If you do not expect "the guidance to have any teeth, nor for it to have any impact on implementations", what exactly are you hoping to achieve?

> There is the question about non-caching intermediaries that might otherwise perform logging.  They aren't always going to look at Cache-Control unless they need to (for no-transform), so a caveat along the lines of "this is NOT a reliable or sufficient mechanism" might need to be added for this.
> 
> That leaves me with (for p6, S3.2.1 & S3.2.2):
> 
>  An intermediary that performs logging (whether or not it implements a cache) MUST NOT perform logging for requests or responses with a no-store directive.
> 

Apart from the fact that I'm not aware of an implementation that associates such a semantic with no-store, given the reasons that logging is often enabled (e.g. debugging, reporting, billing, etc.) I simply don't see that it is likely that implementations will adhere to the stated requirement to not log requests/responses containing no-store and therefore having a specification mandate something that few if any implementations will adhere to seems entirely pointless to me. It has nothing to do with inter-operation and at best will give some subset of folks the impression that using no-store will provide some additional level of privacy that in practice will be non-existent.

Ben
Received on Tuesday, 3 May 2011 22:44:44 GMT

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