[A83] Re: 83p os


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[A83] Re: 83p os



Jeff writes:
> I agree, yet am confused at the reasoning behind factoring a 512 bit
> number ;)

Programs must be signed using RSA.  To sign your own code, you would need
the key.  The key used on the calculator is 512 bits.  Thus, to sign your
own code, you need to factor a 512 bit number.

It is possible to factor a 512 bit number, but it would not be economically
feasible for you to do so.  It has been done in the past:

http://www.rsasecurity.com/company/news/releases/pr.asp?doc_id=509
http://citeseer.nj.nec.com/431185.html
http://www.ercim.org/publication/Ercim_News/enw39/512.html

There is an old BYTE article from October of 1995 which stated that 512 bit
keys could be broken with then current technology:

http://www.byte.com/art/9510/sec7/art5.htm

Dan Bernstein has some very interesting ideas for special purpose circuits
for factoring using number field sieve.  I would not be surprised if the
next factoring breakthrough comes from him and his work:

http://cr.yp.to/nfscircuit.html
http://cr.yp.to/nfscircuit/rsa.html

RSA Security has a new factoring challenge for factoring even larger
numbers:

http://www.rsasecurity.com/rsalabs/challenges/factoring/

--
David Phillips <david@acz.org>
http://david.acz.org/




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