Subject: [Sipping] History info and privacy

From: "Elwell, John" <[email-masked]>
Date: Wed, 18 Dec 2002 15:14:27 +0000

I have a concern that I don't think is addressed by
draft-ietf-sipping-req-history-00 and draft-barnes-sipping-history-info-00.
I have had some discussion with the authors, but after failing to come to a
conclusion on this particular point I would like to seek further opinions.

Suppose a call from A towards B is retargeted by B's proxy towards C.
Amongst other things the history-info draft provides a History-info header
to A (if A has indicated support for this header). This header will reveal
to A the request-URI of C. The question is whether this is a good thing from
a privacy point of view.

One aspect of privacy is that B might not wish A to know that he is
retargeting his calls to C (or even that he is retargeting his calls at
all). 

A second aspect is that C might not wish A to know C's identity. One example
is where B is in a company and retargets his calls to a colleague's home AOR
(e.g., to [email-masked] as opposed to [email-masked]). The colleague, C,
has obviously made his home AOR available to B (and hopefully has authorised
B to target calls to that AOR). However, C may not have made his address
public and would not wish it to be disclosed to any caller A.

I would like opinions as to whether each of these privacy concerns are
valid.

John Elwell
e-mail: mailto:[email-masked]

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---

From: "Cullen Jennings" <[email-masked]>
Date: Wed, 18 Dec 2002 09:34:52 -0800

Let's ignore history for a second.

If B forwards the call to C by sending a 302 back to A you have a privacy
problem.

If B proxies the call but is not a B2BUA and reveals the contact address of
C in the 200 back to A or, even worse, the IP address of C in the SDP it
sends to A you have a problem.

My point is that if you want this level of privacy in SIP there are a ton of
headers that you needed to deal with - I fail to see how History makes any
of these problems more complex. Privacy needs to be applied by local policy
and will no doubt be quite complex. If History is revealing information that
you don't want to reveal - the policy could be to just not add it.

Cullen

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of
> Elwell, John
> Sent: Wednesday, December 18, 2002 7:14 AM
> To: [email-masked]'
> Subject: [Sipping] History info and privacy
>
>