A factoring program is a program that performs factorization algorithms.
- GMP-ECM (performing ECM, P-1, and P+1) http://gforge.inria.fr/projects/ecm/
- Msieve (performing Quadratic Sieve and Number Field Sieve) http://www.boo.net/~jasonp/qs.html
- YAFU (performing several factoring methods such as squfof, Pollard's rho method, and ECM) http://sites.google.com/site/bbuhrow/home, also http://sourceforge.net/projects/yafu/
- GGNFS (performing Number Field Sieve) http://sourceforge.net/projects/ggnfs
- CADO-NFS (performing Number Field Sieve) http://cado-nfs.gforge.inria.fr/
- Prime95 (for Windows and MacOSX) and MPrime (for Linux , FreeBSD, and MacOSX) (performing ECM, P-1, and P+1 to search for factors of a × bn ± c) ftp://mersenne.org/gimps/, also http://mersenneforum.org/gimps
- Factor5 (performing Trial factoring of Mersenne numbers) http://www.moregimps.it/billion/download1.php
- PPMPQS (performing MPQS) and PPSIQS (performing SIQS) http://www.asahi-net.or.jp/~KC2H-MSM/cn/index.htm
- Factor (performing several factoring methods such as Pollard's rho method, ECM, and QS) ftp://ftp.computing.dcu.ie/pub/crypto/factor.exe
- mfaktc (performing Trial factoring of Mersenne numbers) CUDA GPU based. See main article for latest version info.
- mfakto OpenCL port of mfaktc.
- MFAC a DOS program that can searches for factors of Double Mersenne numbers and Fermat numbers. Zip available here