If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
As many of us know superficially, lots of public key cryptography is based on the computational difficulty of factoring large numbers. I've never studied that, but maybe other readers of this forum have. Anyone got some good references about integer arithmetic with numbers larger than the computer's natural word size?
Following a challenge by Weston in another thread, I looked up some "sort of big" prime numbers and computed their product: 944,871,244,210,099,859. Then got to thinking, that's not big enough. I bet it could be factored within minutes with an ordinary program on an ordinary computer, written in less than an hour. Anybody want to try that, or show us an online calculator that can do the job?
Then took it to the next level by making the product bigger than 64 bits. Just to separate the men from the boys. (Toddlers from crawlers would be a better analogy). Here's a bigger product of two primes: 1,030,935,892,468,536,050,027. Huge hint: I copied the factors from a familiar web page. If I were challenged to factor that, the trade off would be an hour on Internet searching for a factoring tool, vs. an hour or two writing and benchmarking a primitive factoring program (start with the sub-64 bit problem).
Is anyone else interested in this stuff, but not enough to go factoring yourself? Then I could post one factor, and the much simpler exercise will be to find the other. So far I've done all this work in Excel, using base-1000 or base-10000 arithmetic.
I bet most bitcoin mining is done by people who aren't programmers or mathematicians.
Registered Member #61406
Joined: Thu Jan 05 2017, 11:31PM
Location:
Posts: 268
RSA Rc4/5 convert bytes to bits and store it in array, then do binary maths, in there code. I think just trying to divide a number not with itself or one, and if there's always a carry bit, its a prime. Divide and mulpilcation just loop add or subtract, I think, not sure if there's a short cut.
Registered Member #235
Joined: Wed Feb 22 2006, 04:59PM
Location:
Posts: 80
You would be surprised at the level of skill for some of the first miners. Now you can just buy an ASIC to do the work for you. Most of the public key cryptography is based on elliptic curve cryptography. The issue with finding the private key is the arithmetic is modulo based. Bitcoin uses 256bit modulo arithmetic, in as such the result wraps around many many times. Finding the original private key is solving discrete logarithm problem in O time. Quatum computers could do it with Shor's algorithm.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
large integer arithmetic
