How to get started with Factoring

[DukeBG]

Originally Posted by hansl

Ok, nevermind, I see now that -pm1 1e10 quicky used all 80GB available ram+swap on the second stage and the process was killed. So much higher is definitely out of the question for me anyways.

you can use -maxmem option in gmp-ecm to limit the amount of memory used to what is available for you. It will do the stage 2 longer than if it had all the memory, but still do it.

As for F12 (you can find it in factor db just searching F12), I don't have any proof, but I believe someone would have already ran P-1 with B1=1e10 on it.

[AlienDjinn]

Originally Posted by hansl

Hi, I'm trying to get started on windows 10 64-bit, and have followed the instructions in post #3.

So I extracted to C:\GGNFS and ran again, but got another error this time:

-> procrels -speedtest> PIPE
Traceback (most recent call last):
File "factmsieve-0.86.py", line 2253, in <module>
output_summary(NAME, fact_p, pols_p, poly_p, lats_p)
File "factmsieve-0.86.py", line 1914, in output_summary
timescale = float(re.sub('timeunit:\s*', '', tmp[0]))
IndexError: list index out of range

Is this of any consequence or should I just ignore these errors?

Hans, see my post above. I commented out that code until my python skills are up to par to fix it.

I uploaded that version here: https://github.com/kricketts/of-prime-importance

(In GGNFS.zip -> factmsieve-0.86-fork.py)

--Alien

Works thanks! when you type in python factmsieve-0.86.py RSA110.n it might throw an error even if you have python installed.

Just type: python

And let windows install the python app. Then it should run smoothly and provide the factors in the log file like post #4 suggests!

We will be using this to mine in a new cryptocollectible network!

[bur]

Are the Windows binaries from post #3 still the newest ones available?

[VBCurtis]

Yep- GGNFS hasn't been developed in about ten years, and msieve development ended in '18 or so.

CADO-NFS is the factoring package under active development, and faster for GNFS jobs than GGNFS+msieve. It's not so much faster that GGNFS is dead, say 15-30% faster? Also, CADO uses a slower (but easier to distribute across multiple machines) matrix-solving step, so some folks (EdH is the leading example) use CADO for poly select and sieving and then msieve for matrix to eke out the most speed.

[VictordeHolland]

Composite:
<100 digits --> can be factored by a desktop computer in a hour or less (as long as you use the right tools)
100-110 digits --> a couple of hours using a desktop with quad-core processor or greater
110-120 digits --> less than a day using a desktop with quad-core processor or greater
130 digits --> several days
140 digits --> 10+ days
150 digits --> month+
160 digits --> half a year
>170 digits --> You're mad, or you're working for the NSA!

This was written a few years ago, at that time most desktop computer had Quad-core processors.
In the year 2022 Hexa-, Octa- and more cores are much more common in the mainstream desktop market.
On a modern Intel i7 12700 (12 cores, 20 threads), factoring RSA 100, 110 and 120 are a lot faster now:


RSA-100

Sat May 28 18:58:50 2022 -> Working with NAME = RSA100
...
Sat May 28 19:06:15 2022  p50 factor: 37975227936943673922808872755445627854565536638199
Sat May 28 19:06:15 2022  p50 factor: 40094690950920881030683735292761468389214899724061

Wall time = 7 min 25 sec
---------------------------------------

RSA-110

Sat May 28 19:24:43 2022 -> Working with NAME = RSA110
...
Sat May 28 19:52:28 2022  p55 factor: 5846418214406154678836553182979162384198610505601062333
Sat May 28 19:52:28 2022  p55 factor: 6122421090493547576937037317561418841225758554253106999

Wall time = 27 min 45 sec
---------------------------------------

RSA-120

Sun May 29 11:20:02 2022 -> Working with NAME = RSA120
...
Sun May 29 12:14:03 2022  p60 factor: 327414555693498015751146303749141488063642403240171463406883
Sun May 29 12:14:03 2022  p60 factor: 693342667110830181197325401899700641361965863127336680673013

Wall time = 54 min 1 sec
---------------------------------------

I STRONGLY advice people without experience to first try factoring RSA-100 and/or RSA110!
You need to learn how to setup the tools and gain experience with using them.
If you neglect to do this, you risk wasting a lot of compute resources by selecting sub-optimal settings or typing the wrong commands.

This advice still applies!

[VBCurtis]

Did you use Yafu or CADO to get this timing data?

[henryzz]

Originally Posted by VBCurtis

Did you use Yafu or CADO to get this timing data?

Based on the output I am 90% sure that is Yafu output.
The scaling is also off what I would expect which suggests that parameters are suboptimal to me.