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Re: [saag] On PKI vs. Pinning (SAAG 108 preview)

Michael Richardson <mcr+ietf@sandelman.ca> Fri, 28 August 2020 21:32 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Nico Williams <nico@cryptonector.com>
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Date: Fri, 28 Aug 2020 17:32:00 -0400
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Subject: Re: [saag] On PKI vs. Pinning (SAAG 108 preview)
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Nico Williams <nico@cryptonector.com> wrote:
    >> So, I wanted to do EXACTLY this for IPsec OE (RFC4322).

    > Yeah!

    >> I imagined two entities (Opus and Bill the Cat) sitting in a meadow, doing
    >> security of IPv6-LL addresses without any outside connectivity.
    >> [You can't expect a dead cat to fetch CRLs..]

    > You'd need an IKEv2 extension like Viktor's TLS extension, but which
    > also includes A/AAAA RRsets.

Yes, exactly.  RFC4322 was also going to have a standards track version that
depended upon IKEv2, and RFC4025...but.

    >> I guess this is intended for the TLS WG?

    > Funny story about that.  There had been a TLS WG work item for it that
    > didn't support either the extension pin or the denial of existence
    > chain, and when we pushed for that to be added WG consensus fell apart
    > and the WG dropped the I-D with the agreement that all parties would get
    > to publish their own versions of it on the ISE.

Oh. I feel many beers may be required to understand.
Or perhaps to achieve consensus :-)

    >> > Pinning lets apps detect MITM attacks, but not whether they are
    >> > tolerable attacks (enterprise proxies).
    >>
    >> Agreed.
    >> That would have to come by some attestation statement in the decline.
    >> draft-ietf-capport-api-08 is one place I would like to that.

    > Tolerable attacks are essentially site-local pins that the app needs to
    > decide are OK or not OK, probably by hardcoding an OK/not-OK policy.

Enough that your banking app can say, "Example.COM says you can not connect
securely, please try a different network",  .. and the user can realize that
they are on the example.com guest network.  So, okay.

--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-

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