[36079] in cryptography@c2.net mail archive
Re: Hamiltonian path as protection against DOS.
daemon@ATHENA.MIT.EDU (Adam Back)
Mon Aug 14 21:56:26 2006
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Mon, 14 Aug 2006 17:31:39 -0400
From: Adam Back <adam@cypherspace.org>
To: mikeiscool <michaelslists@gmail.com>
Cc: "James A. Donald" <jamesd@echeque.com>,
cryptography@metzdowd.com, Adam Back <adam@cypherspace.org>
In-Reply-To: <5e01c29a0608131923v763b1287h985797158ab9b8dd@mail.gmail.com>
On Mon, Aug 14, 2006 at 12:23:03PM +1000, mikeiscool wrote:
> But you're imaging an attack with a distributed bot net DDoS'ing you,
> correct? Couldn't they then also use their botnet to process the
> messages faster then normally? They already have the computering
> power. Just a minor addon to the bot client app.
If you're using a hashcash token which takes 20 seconds of your CPU,
it'll slow the spammer down if they owned node has broadband.
(Think about 5k message size, multiple Bcc recipients etc; the spammer
of an owned botnet node can send multple many per second if hashcash
reduces the number of messages that can be sent by a factor of 100,
thats a good thing.)
Whether its enough of a slow down is an open question -- but I think
its difficult to imagine a security protocol that prevent spam with
the attacker owning some big proportion of nodes.
Adam
> Or if it is many requests from one or thousands of clients, can you
> not, per host, ask them to use a cached version? Per X timeout.
>
> Of course, you can't do this with SSL, though.
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