168 lines
4.3 KiB
C++
168 lines
4.3 KiB
C++
#ifndef CHAOS_CIPHER_DES_DESCRYPT_HPP
|
|
#define CHAOS_CIPHER_DES_DESCRYPT_HPP
|
|
|
|
#include <utility>
|
|
|
|
#include "Service/SeArray.hpp"
|
|
|
|
namespace Chaos::Cipher::Des::Inner_
|
|
{
|
|
|
|
struct Bitwise
|
|
{
|
|
template<uint8_t BitsUsed>
|
|
static uint8_t GetBit(uint64_t value, int_fast8_t bitNumber)
|
|
{
|
|
return (value >> (BitsUsed - bitNumber)) & 0b1;
|
|
}
|
|
|
|
template<uint8_t BitsUsed>
|
|
static void SetBit(uint64_t & value, int_fast8_t bitNumber)
|
|
{
|
|
value |= (static_cast<uint64_t>(0b1) << (BitsUsed - bitNumber));
|
|
}
|
|
|
|
template<uint8_t BitsUsedIn, uint8_t BitsUsedOut, typename InputIt>
|
|
static uint64_t TableChoice(uint64_t value, InputIt tableBegin, InputIt tableEnd)
|
|
{
|
|
uint64_t result = 0;
|
|
|
|
int_fast8_t i = 1;
|
|
for (InputIt it = tableBegin; it != tableEnd; ++it, ++i)
|
|
{
|
|
if (GetBit<BitsUsedIn>(value, *it))
|
|
{
|
|
SetBit<BitsUsedOut>(result, i);
|
|
}
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
template<uint8_t Bits>
|
|
static constexpr uint64_t Mask()
|
|
{
|
|
return (static_cast<uint64_t>(0b1) << Bits) - static_cast<uint64_t>(0b1);
|
|
}
|
|
|
|
template<uint8_t BitsUsed>
|
|
static void Rotl(uint64_t & value, int_fast8_t shift)
|
|
{
|
|
value = ((value << shift) | (value >> (BitsUsed - shift))) & Mask<BitsUsed>();
|
|
}
|
|
|
|
template<uint8_t BitsUsedOut>
|
|
static std::pair<uint64_t, uint64_t> Split(uint64_t value)
|
|
{
|
|
return { value >> BitsUsedOut, value & Mask<BitsUsedOut>() };
|
|
}
|
|
|
|
template<uint8_t BitsUsedIn>
|
|
static uint64_t Merge(uint64_t lhs, uint64_t rhs)
|
|
{
|
|
return (lhs << BitsUsedIn) | rhs;
|
|
}
|
|
|
|
template<typename InputIt>
|
|
static uint64_t PackUInt64(InputIt begin, InputIt end)
|
|
{
|
|
uint64_t result = 0;
|
|
|
|
int_fast8_t i = 0;
|
|
for (InputIt it = begin; i < 8 && it != end; ++i, ++it)
|
|
{
|
|
result |= static_cast<uint64_t>(*it) << (56 - (i * 8));
|
|
}
|
|
|
|
return result;
|
|
}
|
|
};
|
|
|
|
using RawKeyArray = Service::SeArray<uint8_t, 8>;
|
|
|
|
class KeySchedule
|
|
{
|
|
public:
|
|
using Key64 = uint64_t;
|
|
using Key56 = uint64_t;
|
|
|
|
using RoundKey48 = uint64_t;
|
|
|
|
KeySchedule(const RawKeyArray & rawKeyArray)
|
|
{
|
|
Key56 key56 = Pc1(Bitwise::PackUInt64(rawKeyArray.Begin(), rawKeyArray.End()));
|
|
|
|
auto [c28, d28] = Bitwise::Split<28>(key56);
|
|
|
|
for (int_fast8_t i = 0; i < Schedule_.Size(); ++i)
|
|
{
|
|
if (i == 0 || i == 1 || i == 8 || i == 15)
|
|
{
|
|
Bitwise::Rotl<28>(c28, 1);
|
|
Bitwise::Rotl<28>(d28, 1);
|
|
}
|
|
else
|
|
{
|
|
Bitwise::Rotl<28>(c28, 2);
|
|
Bitwise::Rotl<28>(d28, 2);
|
|
}
|
|
|
|
Schedule_[i] = Pc2(Bitwise::Merge<28>(c28, d28));
|
|
}
|
|
}
|
|
|
|
RoundKey48 operator[](int_fast8_t i) const
|
|
{
|
|
return Schedule_[i];
|
|
}
|
|
|
|
private:
|
|
Service::SeArray<RoundKey48, 16> Schedule_;
|
|
|
|
static Key56 Pc1(Key64 key)
|
|
{
|
|
constexpr int_fast8_t PC1_TABLE[] =
|
|
{
|
|
57, 49, 41, 33, 25, 17, 9,
|
|
1, 58, 50, 42, 34, 26, 18,
|
|
10, 2, 59, 51, 43, 35, 27,
|
|
19, 11, 3, 60, 52, 44, 36,
|
|
63, 55, 47, 39, 31, 23, 15,
|
|
7, 62, 54, 46, 38, 30, 22,
|
|
14, 6, 61, 53, 45, 37, 29,
|
|
21, 13, 5, 28, 20, 12, 4
|
|
};
|
|
|
|
static_assert(std::size(PC1_TABLE) == 56);
|
|
|
|
return Bitwise::TableChoice<64, 56>(key,
|
|
PC1_TABLE,
|
|
PC1_TABLE + std::size(PC1_TABLE));
|
|
}
|
|
|
|
static RoundKey48 Pc2(Key56 key)
|
|
{
|
|
constexpr int_fast8_t PC2_TABLE[] =
|
|
{
|
|
14, 17, 11, 24, 1, 5,
|
|
3, 28, 15, 6, 21, 10,
|
|
23, 19, 12, 4, 26, 8,
|
|
16, 7, 27, 20, 13, 2,
|
|
41, 52, 31, 37, 47, 55,
|
|
30, 40, 51, 45, 33, 48,
|
|
44, 49, 39, 56, 34, 53,
|
|
46, 42, 50, 36, 29, 32
|
|
};
|
|
|
|
static_assert(std::size(PC2_TABLE) == 48);
|
|
|
|
return Bitwise::TableChoice<56, 48>(key,
|
|
PC2_TABLE,
|
|
PC2_TABLE + std::size(PC2_TABLE));
|
|
}
|
|
};
|
|
|
|
} // namespace Chaos::Cipher::Des::Inner_
|
|
|
|
#endif // CHAOS_CIPHER_DES_DESCRYPT_HPP
|