Exact Large Finite Field Linear Algebra Library (e.g. GF(2^128) / GF(2^256) )

c++, computer-algebra-systems, finite-field, linear-algebra, math

Solution

The NTL library seems to work, using this (sorry I'm quite unable to program in C++) code

#include <NTL/GF2E.h>
#include <NTL/GF2EX.h>
#include <NTL/GF2X.h>
#include <NTL/GF2XFactoring.h>

NTL_CLIENT

int main()
{
    GF2X P = BuildIrred_GF2X(256);
    GF2E::init(P);

    GF2E zero = GF2E::zero();
    GF2E one;
    GF2E r = random_GF2E();
    GF2E r2 = random_GF2E();
    conv(one, 1L);
    cout << "Cardinality: " << GF2E::cardinality() << endl;
    cout << "ZERO: " << zero << " --> " << IsZero(zero) << endl;
    cout << "ONE:  " << one  << " --> " << IsOne(one)   << endl;
    cout << "1/r:  " << 1/r  << ", r * (1/r): " << (r * (1/r)) << endl;
    cout << "1/r2:  " << 1/r2  << ", r2 * (1/r2): " << (r2 * (1/r2)) << endl;
}

it seems to work, proof (output of this program):

Cardinality: 115792089237316195423570985008687907853269984665640564039457584007913129639936
ZERO: [] --> 1
ONE:  [1] --> 1
1/r:  [0 1 0 1 1 0 1 1 1 0 1 1 1 0 0 1 1 0 1 1 1 0 1 1 0 0 0 0 0 1 0 1 0 1 1 0 1 1 0 0 0 0 0 0 1 1 1 0 1 1 1 0 1 0 1 0 0 0 1 1 1 0 1 1 1 1 0 1 0 1 0 1 1 0 1 1 1 0 0 0 1 0 0 1 0 1 1 1 0 1 1 0 1 1 0 0 0 0 0 1 1 0 1 0 1 0 0 0 0 0 1 0 0 1 1 0 0 1 0 0 1 0 1 1 1 1 0 0 1 1 0 1 0 1 1 1 1 1 1 0 1 1 0 0 0 0 0 1 1 0 1 0 0 1 1 1 0 1 1 1 1 1 0 1 0 1 0 0 0 1 1 0 0 1 1 0 0 1 0 1 1 1 0 1 1 1 1 1 0 1 1 0 1 1 1 1 0 1 0 0 0 0 1 1 1 0 1 1 1 0 1 1 1 1 1 1 1 1 0 1 0 1 0 0 1 1 0 1 1 0 1 1 1 1 1 0 0 1 1 0 1 0 1 0 0 0 0 1 1 0 0 1 1 1 0 1], r * (1/r): [1]
1/r2:  [1 0 1 1 0 0 0 0 1 0 1 0 0 0 1 0 0 0 1 1 0 0 1 0 1 0 0 0 1 1 1 0 0 0 1 1 1 1 1 0 1 0 1 1 0 0 1 1 1 0 1 0 1 0 0 1 0 0 0 0 1 1 1 0 0 0 1 1 1 1 1 0 0 1 0 0 0 1 1 0 1 0 1 1 1 0 0 1 0 1 0 1 0 0 1 0 0 0 1 0 0 1 1 1 1 1 0 0 0 0 1 1 1 0 1 0 1 0 1 0 0 0 1 0 1 0 1 1 0 0 0 1 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 1 1 1 0 1 1 0 0 0 0 1 1 0 1 1 1 0 1 0 0 0 0 0 1 1 0 1 1 1 0 0 0 0 1 1 0 1 0 0 0 0 1 0 0 0 0 1 1 1 1 1 0 1 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 1 0 1 1 1 0 1 0 0 0 0 1 0 1 1 0 0 0 1 1 0 0 1 1 0 1 0 0 1 0 1 0 0 1 1], r2 * (1/r2): [1]

Even inverting seems to work (scroll as right as possible in the output sample above) :-)

Problem

General I'm looking for a library that is able to do exact calculations on large finite fields such as GF(2128)/2128 and GF(2256)/2256. I listed the features that I need and the features that would be cool below. Obviously, the library should be as fast as possible :-). Ah, since I'm no C++ master (and probably most of the libraries are C++), sample code of say generate a random element/a constant and multiply it to it's multiplicative inverse Must-Have Features - Addition of field elements - Multiplication of field element - Find the multiplicative inverse of a field element Nice to Have Features - Vector/Matrix support - Random Element support Libraries I already looked at that will probably not work - FFLAS/FFPACK, seems not to work with such large finite fields - Givaro, seems not to work on such large finite fields Libraries I already looked at that could work (but I was unable to use) - NTL, I was not able to invert an element, but it should really work since SAGE seems to use this library when defining GF(2^256) and there an element can be inverted using `x^(-1)` - PARI/GP, I was not able to find everything I need in the documentation, but the SAGE documentation kind of says that it should work Other notes - I'm writing a Haskell program and will interface that library later, so easier Haskell interfacing is better :-)

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