draft paper: "Deploying a New Hash Algorithm"

[Steven M. Bellovin]

In message <7d752ae30508040723d2376a5 at mail.gmail.com>, Steve Furlong writes:
>> [Moderator's note: ... attackers are often cleverer than protocol
>> designers. ...
>
>Is that true? Or is it a combination of
>
>(a) a hundred attackers for every designer, and
>(b) vastly disparate rewards: continued employment and maybe some
>kudos for a designer or implementer, access to $1,000,000,000 of bank
>accounts for an attacker
>

I'd have phrased it differently than Perry did.  I'd say that the 
attackers are often cleverer *about security* than protocol designers, 
because insecurity is their specialty.  Ordinary protocol desingers are 
good at designing those protocols, but they haven't been trained to 
think about security.  Here's how I put it in my talk at the IETF 
plenary last night:

\ns{Patterns of Thought}  
\item   Serial number 1 of any new device is delivered to your enemy.
\item   You hand your packets to your enemy for delivery.
\item   Your enemy is just as smart as you are.  If we haven't seen
        a given class of attack yet, it's because it hasn't been necessary;
        simpler attacks have worked well enough.  (Besides, how do you know
        if you'll actually notice it?)
\endns


		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb



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