Re: [saag] can an on-path attacker drop traffic?

Peter Gutmann <pgut001@cs.auckland.ac.nz> Sun, 04 October 2020 04:43 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Dan Harkins <dharkins@lounge.org>, Eric Rescorla <ekr@rtfm.com>, "Fernando Gont" <fernando@gont.com.ar>
CC: Michael Richardson <mcr+ietf@sandelman.ca>, IETF SAAG <saag@ietf.org>
Thread-Topic: [saag] can an on-path attacker drop traffic?
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Date: Sun, 4 Oct 2020 04:42:46 +0000
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Subject: Re: [saag] can an on-path attacker drop traffic?
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Dan Harkins <dharkins@lounge.org> writes:

>Which is fine but what use do you see in a protocol that is secure against
>this "limited attacker" but not against the more powerful attacker?

Because it's far easier to deploy a relatively straightforward, realistic
protocol secure against a general attack than it is to deply an awkward,
complex, impractical protocol that's theoretically (but often not practically)
secure against a more unlimited attacker.  To quote the end of John Gordon's
joke:

  Now most people in Alice's position would give up. Not Alice. She has
  courage which can only be described as awesome. Against all odds, over a
  noisy telephone line, tapped by the tax authorities and the secret police,
  Alice will happily attempt, with someone she doesn't trust, whom she cannot
  hear clearly, and who is probably someone else, to fiddle her tax returns
  and to organize a coup d'etat, while at the same time minimizing the cost of
  the phone call.

  A coding theorist is someone who doesn't think Alice is crazy.

I don't need a theoretically perfect protocol that's practically un-
deployable, I just need something that's practical and good enough for the
job.

Peter.