How long it takes to factoring the 512-bit number?

[Pepek]

Hi, I am new to msieve and factoring. I need to break down 512-bit (154-digits) number.

What's the approximate time it takes? Is there any way how can I speed up the process? Thanks a lot.

[xilman]

Originally Posted by Pepek

Hi, I am new to msieve and factoring. I need to break down 512-bit (154-digits) number.

What's the approximate time it takes? Is there any way how can I speed up the process? Thanks a lot.

Roughly speaking a cpu-month. It depends on what kind of cpu you have, of course, and whether it is January or February.

To speed up the process, use more and faster computers.

[debrouxl]

Factoring 512-bit RSA keys with NFS was easy in 2009, it's even easier three years later.
BTW, Pepek: ggnfs is much more suitable for NFS sieving than msieve is.

[Dubslow]

Originally Posted by debrouxl

Factoring 512-bit RSA keys with NFS was easy in 2009, it's even easier three years later.
BTW, Pepek: ggnfs is much more suitable for NFS sieving than msieve is.

For poly select, use Msieve; for sieving, use GGNFS (if you ask nicely, someone around here can point you to any executables you might need), and for post-processing, use Msieve again.

Edit: It's probably simplest for a beginner to use YAFU to automate all the individual tasks. Msieve is a part of YAFU, though you will still need to get separate GGNFS siever binaries and then point YAFU to them. (Don't use the files shown on the GGNFS SourceForge page; those are years out of date.)

[chris2be8]

Another good place to start is http://gilchrist.ca/jeff/factoring/n...ers_guide.html

Chris

[Dubslow]

Originally Posted by chris2be8

Another good place to start is http://gilchrist.ca/jeff/factoring/n...ers_guide.html

Chris

Hmm... apparently its poly-select is not multithreaded, which could help a lot...