fermat_factor

fermat_factor, a C code which uses Fermat's factorization method to decompose an integer N into the product of two factors, N = A^2-B^2 = (A+B)*(A-B).

The algorithm seeks to write N = A^2 - B^2 = ( A + B ) * ( A - B ).

Licensing:

The information on this web page is distributed under the MIT license.

Languages:

fermat_factor is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.

Related Data and Programs:

fermat_factor_test

is_prime, a C code which determines if a given integer n is prime, using various versions of the sieve of Eratosthenes.

prime_pi, a C code which evaluates Pi(n), the number of primes less than or equal to an integer n.

Reference:

1. Manon Bischoff,
   This more than 380-year-old trick can crack some modern encryption,
   Spektrum der Wissenschaft,
   09 April 2025.

Source Code:

• fermat_factor.c, the source code.
• fermat_factor.h, the include file.
• fermat_factor.sh, compiles the source code.