[A83] Re: DS Thread Extended onto this list


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[A83] Re: DS Thread Extended onto this list



Let's ask distributed.net!

> (Lurk mode off :)
> 
> >(See, to  emulate the restriction, you'd have to know how to check for
> it, 
> >thus how to break it . . . )
> 
> Not necesarrily.  Actually checing to see if the os image is valid is 
> probably pretty easy.  I assume the TI-83 does it in software, which means
> 
> both that VTI already checks the images (by vitrue of emulating the 
> calculator), and also anyone clever as disassembly could figure out how it
> 
> works.  It's actually signing an OS image that's a bitch.
> 
> I assume (though I'm not sure) that the signing system is a variation of 
> very well known and understood public-key encryption.  TI signes their OS 
> with a secret, private-key.  The OS can then be verified using a
> public-key 
> that can be stored in the TI-83 ROM.  Because of some very complicated
> math 
> having to do with number theory, the public key can be calculated using
> the 
> private key, but not the other way around.  This is the way most digital 
> content is securely signed these days.
> 
> Thus, even though you can check to see if data is correctly signed, you
> have 
> no way of actually creating signed data yourself (without years of CPU
> time 
> spend brute-forcing the crypto).
> 
> 
> Stupid like a fox!
> Look ma, I'm an artist: http://aaronstj.deviantart.com
> 
> 
> 
> 
> _________________________________________________________________
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> http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
> 
> 

-- 
Groeten,
    Ronald Teune @School
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