mersenneforum.org Algorithms for "small" numbers?
 Register FAQ Search Today's Posts Mark Forums Read

 2006-03-12, 09:02 #1 Jushi     Sep 2005 UGent 1111002 Posts Algorithms for "small" numbers? I am looking for algorithms to factor numbers of about 64 to 128 bits in size (20 to 39 decimal digits). I guess I should start with trial factoring with primes up to about 20 or 24 bits, but what would you recommend for the larger factors? The numbers I'm trying to factor are basically random, so they don't have any special form. On the other hand, they shouldn't be particularly hard to factor either. I realize this question does not have a well-defined answer, but at least it would help to have an algorithm which is not completely stupid.
 2006-03-12, 09:49 #2 Citrix     Jun 2003 3·5·107 Posts ECM would be the fastest.
2006-03-12, 12:10   #3
wblipp

"William"
May 2003
Near Grandkid

3·7·113 Posts

Quote:
 Originally Posted by Jushi I am looking for algorithms to factor numbers of about 64 to 128 bits in size (20 to 39 decimal digits).
As a starting point you can look at what Dario Alpern has done in his java factoring applet at

http://www.alpertron.com.ar/ECM.HTM

He does trial factoring, then a few ECM curves, then SIQS. His ECM parameters and SIQS transition thresholds are described lower on that page.

 Similar Threads Thread Thread Starter Forum Replies Last Post pinhodecarlos NFS@Home 2 2015-07-04 11:18 gszpetkowski Factoring 13 2014-08-05 11:57 Prime95 PrimeNet 6 2006-05-21 15:38 Fusion_power Math 13 2004-12-28 20:46 antiroach Lone Mersenne Hunters 6 2003-07-16 23:35

All times are UTC. The time now is 06:00.

Fri Feb 3 06:00:24 UTC 2023 up 169 days, 3:28, 1 user, load averages: 1.24, 1.09, 1.01