Re: Address privacy

[Tom Herbert <[e-mail]>]

On Mon, Jan 27, 2020, 7:57 PM Fernando Gont <[e-mail]> wrote:

> On 28/1/20 00:10, Tom Herbert wrote:
> > On Mon, Jan 27, 2020 at 5:36 PM Fernando Gont <[e-mail]>
> wrote:
> >>
> >> On 26/1/20 18:37, Nick Hilliard wrote:
> >>> Tom Herbert wrote on 26/01/2020 20:16:
> >>>> It's intuitive
> >>>> that a higher frequency of address rotation yields more privacy
> >>>
> >>> intuitive, but probably inaccurate because of the a priori assumption
> >>> that privacy is strongly associated with the endpoint identifier.
> >>
> >> In many cases, it is: you log in to fb with a given address, and reuse
> >> that address to do other stuf
> >>
> > Yes, that's the "always on" network application that would allow
> > address tracking and identification at even high frequency of address
> > change. An exploit based on that is described in section 4.4 of
> > draft-herbert-ipv6-prefix-address-privacy-00. I believe the only way
> > to defeat this exploit would be single use (per flow), uncorrelated
> > address.
>
> Agreed. That said, temporary addresses, for obvious reasons mitigates
> activity correlation over time -- certainly not to the same extent that
> the paranoid "one address per flow" would.
>

Fernando,

The rationale for temporary addresses may be obvious, but I don't believe
anyone has yet quantified the effects. For instance, RFC4941 is thirteen
years old, is there any evidence that it has materially improved anyone's
privacy? (I'm not being cynical, but I think it's a fair question).

One might compare this to the policy of some sys admins that users need to
change passwords regularly. The rationale is similar, but that practice has
been most debunked as not improving security and in fact is more of a
burden to users that providing any real value.

Tom



> Thanks,
> --
> Fernando Gont
> SI6 Networks
> e-mail: [e-mail]
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
>
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