ladybird/Userland/Libraries/LibCrypto/NumberTheory/ModularFunctions.h
2021-01-12 12:17:46 +01:00

72 lines
2.8 KiB
C++

/*
* Copyright (c) 2020, Ali Mohammad Pur <ali.mpfard@gmail.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/Random.h>
#include <LibCrypto/BigInt/UnsignedBigInteger.h>
//#define NT_DEBUG
namespace Crypto {
namespace NumberTheory {
UnsignedBigInteger ModularInverse(const UnsignedBigInteger& a_, const UnsignedBigInteger& b);
UnsignedBigInteger ModularPower(const UnsignedBigInteger& b, const UnsignedBigInteger& e, const UnsignedBigInteger& m);
// 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(const IntegerType& b, const IntegerType& 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.divided_by(IntegerType { 2 }).quotient);
// base = base * base
base.set_to(base.multiplied_by(base));
}
return exp;
}
UnsignedBigInteger GCD(const UnsignedBigInteger& a, const UnsignedBigInteger& b);
UnsignedBigInteger LCM(const UnsignedBigInteger& a, const UnsignedBigInteger& b);
UnsignedBigInteger random_number(const UnsignedBigInteger& min, const UnsignedBigInteger& max_excluded);
bool is_probably_prime(const UnsignedBigInteger& p);
UnsignedBigInteger random_big_prime(size_t bits);
}
}