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Libraries: Move to Userland/Libraries/

This commit is contained in:
Andreas Kling 2021-01-12 12:17:30 +01:00
parent dc28c07fa5
commit 13d7c09125
1857 changed files with 266 additions and 274 deletions

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@ -1,359 +0,0 @@
/*
* 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.
*/
#include <LibCrypto/NumberTheory/ModularFunctions.h>
namespace Crypto {
namespace NumberTheory {
UnsignedBigInteger ModularInverse(const UnsignedBigInteger& a_, const UnsignedBigInteger& b)
{
if (b == 1)
return { 1 };
UnsignedBigInteger one { 1 };
UnsignedBigInteger temp_1;
UnsignedBigInteger temp_2;
UnsignedBigInteger temp_3;
UnsignedBigInteger temp_4;
UnsignedBigInteger temp_plus;
UnsignedBigInteger temp_minus;
UnsignedBigInteger temp_quotient;
UnsignedBigInteger temp_remainder;
UnsignedBigInteger d;
auto a = a_;
auto u = a;
if (a.words()[0] % 2 == 0) {
// u += b
UnsignedBigInteger::add_without_allocation(u, b, temp_plus);
u.set_to(temp_plus);
}
auto v = b;
UnsignedBigInteger x { 0 };
// d = b - 1
UnsignedBigInteger::subtract_without_allocation(b, one, d);
while (!(v == 1)) {
while (v < u) {
// u -= v
UnsignedBigInteger::subtract_without_allocation(u, v, temp_minus);
u.set_to(temp_minus);
// d += x
UnsignedBigInteger::add_without_allocation(d, x, temp_plus);
d.set_to(temp_plus);
while (u.words()[0] % 2 == 0) {
if (d.words()[0] % 2 == 1) {
// d += b
UnsignedBigInteger::add_without_allocation(d, b, temp_plus);
d.set_to(temp_plus);
}
// u /= 2
UnsignedBigInteger::divide_u16_without_allocation(u, 2, temp_quotient, temp_remainder);
u.set_to(temp_quotient);
// d /= 2
UnsignedBigInteger::divide_u16_without_allocation(d, 2, temp_quotient, temp_remainder);
d.set_to(temp_quotient);
}
}
// v -= u
UnsignedBigInteger::subtract_without_allocation(v, u, temp_minus);
v.set_to(temp_minus);
// x += d
UnsignedBigInteger::add_without_allocation(x, d, temp_plus);
x.set_to(temp_plus);
while (v.words()[0] % 2 == 0) {
if (x.words()[0] % 2 == 1) {
// x += b
UnsignedBigInteger::add_without_allocation(x, b, temp_plus);
x.set_to(temp_plus);
}
// v /= 2
UnsignedBigInteger::divide_u16_without_allocation(v, 2, temp_quotient, temp_remainder);
v.set_to(temp_quotient);
// x /= 2
UnsignedBigInteger::divide_u16_without_allocation(x, 2, temp_quotient, temp_remainder);
x.set_to(temp_quotient);
}
}
// x % b
UnsignedBigInteger::divide_without_allocation(x, b, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
return temp_remainder;
}
UnsignedBigInteger ModularPower(const UnsignedBigInteger& b, const UnsignedBigInteger& e, const UnsignedBigInteger& m)
{
if (m == 1)
return 0;
UnsignedBigInteger ep { e };
UnsignedBigInteger base { b };
UnsignedBigInteger exp { 1 };
UnsignedBigInteger temp_1;
UnsignedBigInteger temp_2;
UnsignedBigInteger temp_3;
UnsignedBigInteger temp_4;
UnsignedBigInteger temp_multiply;
UnsignedBigInteger temp_quotient;
UnsignedBigInteger temp_remainder;
while (!(ep < 1)) {
if (ep.words()[0] % 2 == 1) {
// exp = (exp * base) % m;
UnsignedBigInteger::multiply_without_allocation(exp, base, temp_1, temp_2, temp_3, temp_4, temp_multiply);
UnsignedBigInteger::divide_without_allocation(temp_multiply, m, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
exp.set_to(temp_remainder);
}
// ep = ep / 2;
UnsignedBigInteger::divide_u16_without_allocation(ep, 2, temp_quotient, temp_remainder);
ep.set_to(temp_quotient);
// base = (base * base) % m;
UnsignedBigInteger::multiply_without_allocation(base, base, temp_1, temp_2, temp_3, temp_4, temp_multiply);
UnsignedBigInteger::divide_without_allocation(temp_multiply, m, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
base.set_to(temp_remainder);
}
return exp;
}
static void GCD_without_allocation(
const UnsignedBigInteger& a,
const UnsignedBigInteger& b,
UnsignedBigInteger& temp_a,
UnsignedBigInteger& temp_b,
UnsignedBigInteger& temp_1,
UnsignedBigInteger& temp_2,
UnsignedBigInteger& temp_3,
UnsignedBigInteger& temp_4,
UnsignedBigInteger& temp_quotient,
UnsignedBigInteger& temp_remainder,
UnsignedBigInteger& output)
{
temp_a.set_to(a);
temp_b.set_to(b);
for (;;) {
if (temp_a == 0) {
output.set_to(temp_b);
return;
}
// temp_b %= temp_a
UnsignedBigInteger::divide_without_allocation(temp_b, temp_a, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
temp_b.set_to(temp_remainder);
if (temp_b == 0) {
output.set_to(temp_a);
return;
}
// temp_a %= temp_b
UnsignedBigInteger::divide_without_allocation(temp_a, temp_b, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
temp_a.set_to(temp_remainder);
}
}
UnsignedBigInteger GCD(const UnsignedBigInteger& a, const UnsignedBigInteger& b)
{
UnsignedBigInteger temp_a;
UnsignedBigInteger temp_b;
UnsignedBigInteger temp_1;
UnsignedBigInteger temp_2;
UnsignedBigInteger temp_3;
UnsignedBigInteger temp_4;
UnsignedBigInteger temp_quotient;
UnsignedBigInteger temp_remainder;
UnsignedBigInteger output;
GCD_without_allocation(a, b, temp_a, temp_b, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder, output);
return output;
}
UnsignedBigInteger LCM(const UnsignedBigInteger& a, const UnsignedBigInteger& b)
{
UnsignedBigInteger temp_a;
UnsignedBigInteger temp_b;
UnsignedBigInteger temp_1;
UnsignedBigInteger temp_2;
UnsignedBigInteger temp_3;
UnsignedBigInteger temp_4;
UnsignedBigInteger temp_quotient;
UnsignedBigInteger temp_remainder;
UnsignedBigInteger gcd_output;
UnsignedBigInteger output { 0 };
GCD_without_allocation(a, b, temp_a, temp_b, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder, gcd_output);
if (gcd_output == 0) {
#ifdef NT_DEBUG
dbgln("GCD is zero");
#endif
return output;
}
// output = (a / gcd_output) * b
UnsignedBigInteger::divide_without_allocation(a, gcd_output, temp_1, temp_2, temp_3, temp_4, temp_quotient, temp_remainder);
UnsignedBigInteger::multiply_without_allocation(temp_quotient, b, temp_1, temp_2, temp_3, temp_4, output);
#ifdef NT_DEBUG
dbg() << "quot: " << temp_quotient << " rem: " << temp_remainder << " out: " << output;
#endif
return output;
}
static bool MR_primality_test(UnsignedBigInteger n, const Vector<UnsignedBigInteger, 256>& tests)
{
// Written using Wikipedia:
// https://en.wikipedia.org/wiki/Miller%E2%80%93Rabin_primality_test#Miller%E2%80%93Rabin_test
ASSERT(!(n < 4));
auto predecessor = n.minus({ 1 });
auto d = predecessor;
size_t r = 0;
{
auto div_result = d.divided_by(2);
while (div_result.remainder == 0) {
d = div_result.quotient;
div_result = d.divided_by(2);
++r;
}
}
if (r == 0) {
// n - 1 is odd, so n was even. But there is only one even prime:
return n == 2;
}
for (auto a : tests) {
// Technically: ASSERT(2 <= a && a <= n - 2)
ASSERT(a < n);
auto x = ModularPower(a, d, n);
if (x == 1 || x == predecessor)
continue;
bool skip_this_witness = false;
// r 1 iterations.
for (size_t i = 0; i < r - 1; ++i) {
x = ModularPower(x, 2, n);
if (x == predecessor) {
skip_this_witness = true;
break;
}
}
if (skip_this_witness)
continue;
return false; // "composite"
}
return true; // "probably prime"
}
UnsignedBigInteger random_number(const UnsignedBigInteger& min, const UnsignedBigInteger& max_excluded)
{
ASSERT(min < max_excluded);
auto range = max_excluded.minus(min);
UnsignedBigInteger base;
auto size = range.trimmed_length() * sizeof(u32) + 2;
// "+2" is intentional (see below).
// Also, if we're about to crash anyway, at least produce a nice error:
ASSERT(size < 8 * MiB);
u8 buf[size];
AK::fill_with_random(buf, size);
UnsignedBigInteger random { buf, size };
// At this point, `random` is a large number, in the range [0, 256^size).
// To get down to the actual range, we could just compute random % range.
// This introduces "modulo bias". However, since we added 2 to `size`,
// we know that the generated range is at least 65536 times as large as the
// required range! This means that the modulo bias is only 0.0015%, if all
// inputs are chosen adversarially. Let's hope this is good enough.
auto divmod = random.divided_by(range);
// The proper way to fix this is to restart if `divmod.quotient` is maximal.
return divmod.remainder.plus(min);
}
bool is_probably_prime(const UnsignedBigInteger& p)
{
// Is it a small number?
if (p < 49) {
u32 p_value = p.words()[0];
// Is it a very small prime?
if (p_value == 2 || p_value == 3 || p_value == 5 || p_value == 7)
return true;
// Is it the multiple of a very small prime?
if (p_value % 2 == 0 || p_value % 3 == 0 || p_value % 5 == 0 || p_value % 7 == 0)
return false;
// Then it must be a prime, but not a very small prime, like 37.
return true;
}
Vector<UnsignedBigInteger, 256> tests;
// Make some good initial guesses that are guaranteed to find all primes < 2^64.
tests.append(UnsignedBigInteger(2));
tests.append(UnsignedBigInteger(3));
tests.append(UnsignedBigInteger(5));
tests.append(UnsignedBigInteger(7));
tests.append(UnsignedBigInteger(11));
tests.append(UnsignedBigInteger(13));
UnsignedBigInteger seventeen { 17 };
for (size_t i = tests.size(); i < 256; ++i) {
tests.append(random_number(seventeen, p.minus(2)));
}
// Miller-Rabin's "error" is 8^-k. In adversarial cases, it's 4^-k.
// With 200 random numbers, this would mean an error of about 2^-400.
// So we don't need to worry too much about the quality of the random numbers.
return MR_primality_test(p, tests);
}
UnsignedBigInteger random_big_prime(size_t bits)
{
ASSERT(bits >= 33);
UnsignedBigInteger min = UnsignedBigInteger::from_base10("6074001000").shift_left(bits - 33);
UnsignedBigInteger max = UnsignedBigInteger { 1 }.shift_left(bits).minus(1);
for (;;) {
auto p = random_number(min, max);
if ((p.words()[0] & 1) == 0) {
// An even number is definitely not a large prime.
continue;
}
if (is_probably_prime(p))
return p;
}
}
}
}