Re: [Rats] Android comments on EAT draft

[Shawn Willden <[e-mail]>]

On Fri, Jul 5, 2019 at 12:28 PM Michael Richardson <[e-mail]>
wrote:

>
> Shawn Willden <swillden=[e-mail]> wrote:
>     > Specifically, EAT is about attesting to a *device* while Keystore
>     > Attestation is about attesting to a *key* -- though we also attest to
>     > quite
>
> I have include a section in the use case document called "Cryptographic key
> Attestion"
>

Great!


>     > Another, more tractable, area of difference is that EAT provides
> Claims
>     > for
>     > several data items which Android will likely never allow to be
> attested
>     > because of their privacy implications and potential for ecosystem
>     > fragmentation (apps choosing which devices they'll run on -- we
> generally
>     > try to deny them the information they'd like to have to make those
>     > choices).  These are:
>
>     > - UEID
>     > - Origination
>     > - Location
>
> Can you say more about location?
> Are you saying that Android would never provide a relying party (say, an
> open-protocol implementation of Pokemon GO) with where a device is?
>

I strongly doubt that we will ever provide that.  I understand the
benefits, but the privacy team feels like the risks are too great, that
it's important that it always be possible to spoof privacy-critical data
elements like location.


>     > Some other claims that we have, and think are important, are OS
> version
>     > and
>     > patch-level (represented as a date, YYYYMMDD); secure boot
> verification
>     > key
>     > digest; secure boot digest (hash of all verified code); application
> ID (a
>     > digest of the requesting app signing key); and secure app version
> (hmm,
>     > don't have a patchlevel, but we should!  I'll see about adding that
> for
>     > R).
>
> These are all intended to be covered under "network attestation", but
> now I wonder if that term is mis-leading.
>

Hmm.  Yes, you're attesting to the device state, not anything about a
network.  I guess "network attestation" is because you're expecting the
relying party to be the network?


-- 
Shawn Willden | Staff Software Engineer | [e-mail] | 720-924-6645