Re: 6man w.g. last call for <draft-ietf-6man-default-iids-11.txt>

[Alissa Cooper <[e-mail]>]

Hi Lorenzo,

> On May 13, 2016, at 8:29 PM, Lorenzo Colitti <[e-mail]> wrote:
> 
> On Sat, May 14, 2016 at 12:00 PM, Brian E Carpenter <[e-mail] <mailto:[e-mail]>> wrote:
> Because if someone is trying to correlate different types of my traffic,
> let's say something sent over IPX and something sent over IPv6, the task
> will be made easier if the lower 48 bits are the same in both types of
> traffic. (Obviously, someone on-link can use ND to correlate MAC address
> and IP address, so we're talking about someone observing off-link packets.)
> 
> That seems extremely unlikely to happen in practice, given that the vast majority of hosts either don't have an IPX stack at all or have it disabled by default, and embedding a MAC address in a protocol payload is not very useful so people tend not to do it.
> 
> By contrast, here is one weakness that is pretty much mandated by this draft as written: because addresses have to be stable,

The draft does not require addresses to be stable. It changes the recommendations about how to generate an address in cases where a stable address was desired anyway.

> any remote attacker anywhere on the Internet that ever exchanges a packet with that host can track it every time the host visits the same network, *forever*, with no recourse. Section 3 point 1.
> 
> Either we fix that or we stop asserting that this draft is motivated by privacy considerations.

I would frankly be thrilled if we could get away from stable addresses altogether. But I’m skeptical about the feasibility of achieving consensus around that at present. Defining the approach in this draft in the meantime is certainly motivated by consideration for privacy improvement for me, even if that improvement is incremental.

Alissa

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