Add DES key schedule pre-draft implementation

Chaos/Cipher/Des/DesCrypt.hpp

@@ -0,0 +1,162 @@
+#ifndef CHAOS_CIPHER_DES_DESCRYPT_HPP
+#define CHAOS_CIPHER_DES_DESCRYPT_HPP
+
+#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;
+    }
+};
+
+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)
+    {
+        Key64 key64 = 0;
+
+        key64 |= static_cast<Key64>(rawKeyArray[7]) <<  0;
+        key64 |= static_cast<Key64>(rawKeyArray[6]) <<  8;
+        key64 |= static_cast<Key64>(rawKeyArray[5]) << 16;
+        key64 |= static_cast<Key64>(rawKeyArray[4]) << 24;
+        key64 |= static_cast<Key64>(rawKeyArray[3]) << 32;
+        key64 |= static_cast<Key64>(rawKeyArray[2]) << 40;
+        key64 |= static_cast<Key64>(rawKeyArray[1]) << 48;
+        key64 |= static_cast<Key64>(rawKeyArray[0]) << 56;
+
+        Key56 key56 = Pc1(key64);
+
+        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