Subject: (IPng 7542) Privacy concern with globally unique interface id number

From: Dan Kneip <[email-masked]>
Date: Tue, 18 May 1999 13:08:26 -0500

After hearing and reading a little about the Pentium III Processor
Serial Number (PSN) and the privacy concern, I read about the desire
to use a globally unique number for the interface id portion of the
IPv6 address, such as one of the IEEE MAC address standards (48/64
bit). 

Doesn't this seem to bring up the same concern?

Can anyone address this concern?

Just curious.

Dan Kneip
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From: Robert Elz <[email-masked]>
Date: Wed, 19 May 1999 04:57:34 +1000

Date:        Tue, 18 May 1999 13:08:26 -0500
    From:        Dan Kneip <[email-masked]>
    Message-ID:  <[email-masked]>

  | Doesn't this seem to bring up the same concern?

Not really.   Embedded MAC addresses are just one (easy) way to
assign IPv6 addresses locally.   Anyone who doesn't like that way
is perfectly free to assign their addresses using whatever other
scheme they like.

kre

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From: Shane Kerr <[email-masked]>
Date: Tue, 18 May 1999 16:03:24 -0400 (EDT)

On Tue, 18 May 1999, Dan Kneip wrote:

> Serial Number (PSN) and the privacy concern, I read about the desire to
> use a globally unique number for the interface id portion of the IPv6
> address, such as one of the IEEE MAC address standards (48/64 bit).
> 

This concern was raised at the last IETF.  IIRC, it was placed in the,
"huh, this may be bad and maybe we should do something about it" category.
Kind of like multi-homing.  ;)  

All of the obvious suggestions apply, but I don't think any have made it
as far as a draft (although I could be wrong).

--
Shane Kerr <[email-masked]>
Software Engineer
American Registry for Internet Numbers

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From: "Matt Crawford" <[email-masked]>
Date: Tue, 18 May 1999 15:21:28 -0500

> Kind of like multi-homing.  ;)  

I thought someone took it as a work item.  I've prodded that person.
We'll see.
				Matt

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From: Peter Tattam <[email-masked]>
Date: Wed, 19 May 1999 10:27:10 +1000 (EST)

There was a recent furore over ethernet addresses leaking out via some MS
document like Word or Excel or something - can't remember the full story.  The
same group of people would complain about EUI addresses.  I was going to raise
this issue as well - glad someone else has perceived the same issue.

Peter

--
Peter R. Tattam                            [email-masked]
Managing Director,    Trumpet Software International Pty Ltd
Hobart, Australia,  Ph. +61-3-6245-0220,  Fax +61-3-62450210

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From: Brian E Carpenter <[email-masked]>
Date: Wed, 19 May 1999 10:48:48 +0100

I thought this was a non-issue. It surely doesn't matter for
link-local addresses (they are only visible locally:) and for
anything else, the paranoid can use whatever arbitrary value
they want in the ID field. The practical thing that needs to be 
done is finishing off DHCPv6.

  Brian

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From: Thomas Narten <[email-masked]>
Date: Wed, 19 May 1999 06:59:36 -0400

> I thought someone took it as a work item.  I've prodded that person.

I believe I am that person.

At the interim meeting in Grenoble, we discussed this issue. I don't
believe that that the way IPv6 uses MAC addresses in forming addresses
leads to the exact same concerns as have been raised with Intel's
chip-embedded serial number. For example,

- many machines have associated DNS names. If the DNS name stays the
  same over time, this is little different than the address staying
  the same over a long period of time. In practice, this is often the
  case today (e.g., I have an ADSL-connected home machine that uses
  DHCP to get an address. I always get the same address and DNS name).

- switching network adaptors automatically results in a different
  address. 

- one could use DHCP, in which case the interface ID wouldn't need to
  be the MAC address. Plus, the server could change the address used
  over time to prevent the same one from being used for an extended
  period of time.

- its not clear that the privacy issues are significantly worse than
  the way the web uses cookies, a practice that is widespread.

Finally, as kre mentions, it's pretty straightforward to use a
different Interface ID if you want to use a different address (e.g.,
my manually configuring a token).  The action item I have is to
produce a draft describing how one could automate this in stateless
address autoconfiguration. The basic idea would be to take the EUI
identifier as today, but run it through some sort of hash function to
produce a different identifier, and generate an IPv6 address from it.
To ensure that addresses change over time, one could (for example)
upon reboot hash to a new Interface ID using the previous value as a
input to the hash.  This would be an optional standalone document that
complements but does not replace the existing stateless address
autoconfiguration document.

Thomas

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From: "Matt Crawford" <[email-masked]>
Date: Wed, 19 May 1999 11:53:28 -0500

> The action item I have is to produce a draft describing how one
> could automate this in stateless address autoconfiguration. The
> basic idea would be ...

Exactly the item I was referring to.  As we agreed in February, this
needs to be out there and be seen.
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