gmp-ecm is from Paul Zimmermann, and is based on the
GMP multiprecision library.

The history of this work is as follows:

Richard Brent has predicted in 1985 in a paper entitled Some Integer
Factorization Algorithms using Elliptic Curves that factors up to 50
digits could by found by the Elliptic Curve Method (ECM). Indeed,
Peter Montgomery found in November 1995 a factor of 47 digits of
5^256+1, and Richard Brent set in October 1997 a new genuine record
with a factor of 48 digits of 24^121+1. 

This information thanks to the ECMNET Project, located here:

	http://www.loria.fr/~zimmerma/records/ecmnet.html

(The Richard Brent paper is also mirrored in this directory as rpb102.dvi.gz)