BeamMP-Server/include/Cryptography.h
2024-01-23 21:00:11 +01:00

131 lines
4.2 KiB
C++

// BeamMP, the BeamNG.drive multiplayer mod.
// Copyright (C) 2024 BeamMP Ltd., BeamMP team and contributors.
//
// BeamMP Ltd. can be contacted by electronic mail via contact@beammp.com.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
#pragma once
#include <array>
#include <cstdarg>
#include <string>
namespace Crypto {
constexpr auto time = __TIME__;
constexpr auto seed = static_cast<int>(time[7]) + static_cast<int>(time[6]) * 10 + static_cast<int>(time[4]) * 60 + static_cast<int>(time[3]) * 600 + static_cast<int>(time[1]) * 3600 + static_cast<int>(time[0]) * 36000;
// 1988, Stephen Park and Keith Miller
// "Random Number Generators: Good Ones Are Hard To Find", considered as "minimal standard"
// Park-Miller 31 bit pseudo-random number generator, implemented with G. Carta's optimisation:
// with 32-bit math and without division
template <int N>
struct RandomGenerator {
private:
static constexpr unsigned a = 16807; // 7^5
static constexpr unsigned m = 2147483647; // 2^31 - 1
static constexpr unsigned s = RandomGenerator<N - 1>::value;
static constexpr unsigned lo = a * (s & 0xFFFFu); // Multiply lower 16 bits by 16807
static constexpr unsigned hi = a * (s >> 16u); // Multiply higher 16 bits by 16807
static constexpr unsigned lo2 = lo + ((hi & 0x7FFFu) << 16u); // Combine lower 15 bits of hi with lo's upper bits
static constexpr unsigned hi2 = hi >> 15u; // Discard lower 15 bits of hi
static constexpr unsigned lo3 = lo2 + hi;
public:
static constexpr unsigned max = m;
static constexpr unsigned value = lo3 > m ? lo3 - m : lo3;
};
template <>
struct RandomGenerator<0> {
static constexpr unsigned value = seed;
};
template <int N, int M>
struct RandomInt {
static constexpr auto value = RandomGenerator<N + 1>::value % M;
};
template <int N>
struct RandomChar {
static const char value = static_cast<char>(1 + RandomInt<N, 0x7F - 1>::value);
};
template <size_t N, int K, typename Char>
struct MangleString {
private:
const char _key;
std::array<Char, N + 1> _encrypted;
constexpr Char enc(Char c) const {
return c ^ _key;
}
Char dec(Char c) const {
return c ^ _key;
}
public:
template <size_t... Is>
constexpr MangleString(const Char* str, std::index_sequence<Is...>)
: _key(RandomChar<K>::value)
, _encrypted { enc(str[Is])... } { }
decltype(auto) decrypt() {
for (size_t i = 0; i < N; ++i) {
_encrypted[i] = dec(_encrypted[i]);
}
_encrypted[N] = '\0';
return _encrypted.data();
}
};
static auto w_printf = [](const char* fmt, ...) {
va_list args;
va_start(args, fmt);
vprintf(fmt, args);
va_end(args);
};
static auto w_printf_s = [](const char* fmt, ...) {
va_list args;
va_start(args, fmt);
vprintf(fmt, args);
va_end(args);
};
static auto w_sprintf_s = [](char* buf, size_t, const char* fmt, ...) {
va_list args;
va_start(args, fmt);
vsprintf(buf, fmt, args);
va_end(args);
};
static auto w_sprintf_s_ret = [](char* buf, size_t, const char* fmt, ...) {
int ret;
va_list args;
va_start(args, fmt);
ret = vsprintf(buf, fmt, args);
va_end(args);
return ret;
};
#define XOR_C(s) [] { constexpr Crypto::MangleString< sizeof(s)/sizeof(char) - 1, __COUNTER__, char > expr( s, std::make_index_sequence< sizeof(s)/sizeof(char) - 1>() ); return expr; }().decrypt()
#define XOR_W(s) [] { constexpr Crypto::MangleString< sizeof(s)/sizeof(wchar_t) - 1, __COUNTER__, wchar_t > expr( s, std::make_index_sequence< sizeof(s)/sizeof(wchar_t) - 1>() ); return expr; }().decrypt()
#define RAWIFY(s) XOR_C(s)
}