Re: resistance to swamping attacks.

touch@isi.edu Fri, 20 September 1996 17:22 UTC

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Date: Fri, 20 Sep 1996 10:27:56 -0700
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To: kim@morningstar.com, sommerfeld@apollo.hp.com
Subject: Re: resistance to swamping attacks.
Cc: ipsec@TIS.COM
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> > I'm no expert in cryptography, but it seems to me that what is needed is
> > a function which is expensive for the originator of a packet to
> > calculate, but cheap for the receiver to verify.  This will make sure
> > that the source of a swamping attack must have a much larger CPU than
> > the receiver.  I don't know if there are any such functions, but perhaps
> > the cryptographically sophisticated among us could enlighten?
> 
> A simple imbalance in "expense" isn't enough -- what if the attacker
> does a lot of precomputation before launching the attack?

Aren't authentication functions symmetric, almost by definition?

Joe
----------------------------------------------------------------------
Joe Touch - touch@isi.edu		    http://www.isi.edu/~touch/
ISI / Project Leader, ATOMIC-2, LSAM       http://www.isi.edu/atomic2/
USC / Research Assistant Prof.                http://www.isi.edu/lsam/