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- From: brnstnd@nyu.edu (D. J. Bernstein)
- Newsgroups: sci.crypt
- Subject: Re: RSA-129 contest
- Message-ID: <8146.Aug2205.17.2492@virtualnews.nyu.edu>
- Date: 22 Aug 92 05:17:24 GMT
- References: <9208220157.AA02629@ucbvax.Berkeley.EDU>
- Organization: IR
- Lines: 48
-
- In article <9208220157.AA02629@ucbvax.Berkeley.EDU> jbs@WATSON.IBM.COM writes:
- > More to the point it is only about 10
- > times better than simply trying a few million values of m.
-
- 10 times better means about 40% reduction in run time.
-
- We are talking about *years* on a supercomputer---and don't think that
- RSA-129 is the only number that anyone wants to factor! I often spend
- time optimizing a section of code responsible for less than one percent
- of the run time of a program---and then another section, another
- section, another section, and all of a sudden I try the program and it's
- five or ten percent faster than before. This is a good thing.
-
- James, if you don't appreciate the value of a 40% speedup, don't
- participate in the contest.
-
- > Since the density of good representations for k*n goes as
- > k**(-9/4) considering multiples of n is unlikely to give a significant
- > improvement.
-
- I don't know what grounds you're arguing from. Nor do I particularly
- care. You were worrying about running out of good polynomials. The fact
- is that multiples of n give polynomials nearly as good as polynomials
- for n itself.
-
- > I must disagree, extensive searches without an accurate figure
- > of merit are basically a waste of time.
-
- If you feel that way, don't participate. Other people have submitted
- good polynomials and I'm sure the current record won't last long. Nobody
- knows an ``accurate figure of merit'' for GNFS polynomials: nobody has
- ever exhibited an accurate method of estimating how much time GNFS will
- use with various parameters, though GNFS detractors always seem to
- pretend otherwise.
-
- The point of this contest is not to find the minimum value of the
- total-coefficients-times-m measure, although that measure isn't bad; the
- reason that I specified an upper limit for that measure was to weed out
- contest entrants who weren't serious. The point of this contest (at
- least as I see it---I can't speak for Arjen Lenstra) is to find a
- reasonable number of reasonably good polynomials in the hope of
- minimizing the time needed for GNFS to factor RSA-129.
-
- > Dan Berstein also posts:
-
- Bernstein. Sure you didn't drop any digits in those polynomials? :-)
-
- ---Dan
-