ladybird/Libraries/LibCrypto/NumberTheory/ModularFunctions.h
devgianlu 1c3d849b8b LibCrypto: Remove unused big numbers modular functions
Remove `Mod`, `ModularInverse`, `ModularPower` and `LCM` as
they are unused.
2025-04-28 12:05:26 +02:00

39 lines
970 B
C++

/*
* Copyright (c) 2020, Ali Mohammad Pur <mpfard@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibCrypto/BigInt/UnsignedBigInteger.h>
namespace Crypto::NumberTheory {
// Note: This function _will_ generate extremely huge numbers, and in doing so,
// it will allocate and free a lot of memory!
// Please use |ModularPower| if your use-case is modexp.
template<typename IntegerType>
static IntegerType Power(IntegerType const& b, IntegerType const& e)
{
IntegerType ep { e };
IntegerType base { b };
IntegerType exp { 1 };
while (!(ep < IntegerType { 1 })) {
if (ep.words()[0] % 2 == 1)
exp.set_to(exp.multiplied_by(base));
// ep = ep / 2;
ep.set_to(ep.shift_right(1));
// base = base * base
base.set_to(base.multiplied_by(base));
}
return exp;
}
UnsignedBigInteger GCD(UnsignedBigInteger const& a, UnsignedBigInteger const& b);
}