[90621] in Cypherpunks
Re: Factor a 2048-bit number
daemon@ATHENA.MIT.EDU (Antonomasia)
Fri Nov 21 14:39:12 1997
Date: Fri, 21 Nov 1997 18:45:09 GMT
From: Antonomasia <ant@notatla.demon.co.uk>
To: cypherpunks@ssz.com
Reply-To: Antonomasia <ant@notatla.demon.co.uk>
Monty Cantsin
> Hint 2: There is an observation which suggests the number may be
> factored. A one word hint will reveal this observation.
> (I want to hold off on Hint 3 for a little while in case somebody is
> already working on the problem. If anybody wants me to withhold Hint
> 3, please post a message to the list and I may do so. It seems to me
> that it will be more fun to solve without Hint 3.)
> Wouldn't it be neat to actually factor a 2048-bit number which was the
> product of two large primes?
The wording of the original challenge suggested there was a trick to
this particular factorisation. My guess that q=p+2 was wrong, so
square rooting (cheap) and using the 2 nearest odd integers was a loser.
--
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