Re: [ieee] Re: Re: Quick Re: to Dick Johnson's Re: COTS scope

[Andrew Berg <andrewb@votehere.com>]

I think that's a little harsh.  A hash built into the machine can be of  
some value, assuming you can account for all of the storage in the machine.

Imagine a hash protocol where instead of always just asking for the hash  
of the entire memory image (which would be easy to forge) we instead asked  
the system for a hash of memory 0x0003221a through 0x0bfffcda (or  
whatever) and it were required to get that right.  If we knew how much  
memory the machine had, by randomly choosing these ranges and comparing  
them with some reference image we could know that it had the correct image.

Unfortunately, this requires us to assume that the machine has only as  
much memory as we think it does, so it's not really perfect.  If there is  
extra, uncounted memory, that extra memory could contain something  
malicious.  But given a simple enough hardware platform, maybe it is good  
enough.

(I'm not really an advocate for hashing myself--I worry about what happens  
if the reference image contains incorrect contents.  Then all we've really  
accomplished is to make sure that exactly the same bad software is running  
everywhere.)

-andrew

On 09 Dec 2004 22:51:46 -0500, Stanley A. Klein <sklein@cpcug.org> wrote:

> At some point I discussed this with Doug Jones.
>
> If the hash test is built into the voting machine, it can be
> compromised.  Just give the right answer even if the test calculates the
> wrong answer.
>
> If it isn't built in, it can be used to install malicious code, just
> like the system built by the Las Vegas slot machine inspector.  He
> didn't get caught for doing that.  He only got caught for an escapade in
> Atlantic City involving Keno and an accomplice who qualifies as one of
> the world's stupidest crooks.  The guy "won" the largest Keno jackpot
> ever in New Jersey, demanded the $100K winnings in cash and refused to
> give his name.  The New Jersey police smelled a rat and wound up
> catching the machine inspector who was the brains behind the fraud.
> Nevada then investigated him and came up with the other fraud.
>
> Either way, the hashing approach can be compromised, especially by
> insiders.
>
>
> Stan Klein

--
andrewb@votehere.com