feat: crypto: Add basic AES keyslot manager

We loads keys from AppData/Alber/sysdata/aes_keys.txt.

NOTE: We do differ from other emulators by not hardcoding the generator key, it's the user responsibility to provide it in aes_keys.txt.

include/crypto/aes_engine.hpp

@@ -0,0 +1,167 @@
+#pragma once
+
+#include <array>
+#include <cstring>
+#include <cstdint>
+#include <climits>
+#include <filesystem>
+#include <optional>
+
+#include "helpers.hpp"
+
+namespace Crypto {
+	constexpr std::size_t AesKeySize = 0x10;
+
+	using AESKey = std::array<uint8_t, AesKeySize>;
+
+	template<std::size_t N>
+	static std::array<uint8_t, N> rolArray(const std::array<uint8_t, N>& value, std::size_t bits) {
+		const auto bitWidth = N * UINT8_WIDTH;
+
+		bits %= bitWidth;
+
+		const auto byteShift = bits / UINT8_WIDTH;
+		const auto bitShift = bits % UINT8_WIDTH;
+
+		std::array<uint8_t, N> result;
+
+		for (std::size_t i = 0; i < N; i++) {
+			result[i] = ((value[(i + byteShift) % N] << bitShift) | (value[(i + byteShift + 1) % N] >> (UINT8_WIDTH - bitShift))) & UINT8_MAX;
+		}
+
+		return result;
+	}
+
+	template<std::size_t N>
+	static std::array<uint8_t, N> addArray(const std::array<uint8_t, N>& a, const std::array<uint8_t, N>& b) {
+		std::array<uint8_t, N> result;
+		std::size_t sum = 0;
+		std::size_t carry = 0;
+
+		for (std::int64_t i = N - 1; i >= 0; i--) {
+			sum = a[i] + b[i] + carry;
+			carry = sum >> UINT8_WIDTH;
+			result[i] = static_cast<std::uint8_t>(sum & UINT8_MAX);
+		}
+
+		return result;
+	}
+
+	template<std::size_t N>
+	static std::array<uint8_t, N> xorArray(const std::array<uint8_t, N>& a, const std::array<uint8_t, N>& b) {
+		std::array<uint8_t, N> result;
+
+		for (std::size_t i = 0; i < N; i++) {
+			result[i] = a[i] ^ b[i];
+		}
+
+		return result;
+	}
+
+	static std::optional<AESKey> createKeyFromHex(const std::string& hex) {
+		if (hex.size() < 32) {
+			return {};
+		}
+
+		AESKey rawKey;
+		for (std::size_t i = 0; i < rawKey.size(); i++) {
+			rawKey[i] = static_cast<uint8_t>(std::stoi(hex.substr(i * 2, 2), 0, 16));
+		}
+
+		return rawKey;
+	}
+
+	struct AESKeySlot {
+		std::optional<AESKey> keyX;
+		std::optional<AESKey> keyY;
+		std::optional<AESKey> normalKey;
+	};
+
+	enum KeySlotId : std::size_t {
+		NCCHKey0 = 0x2C,
+		NCCHKey1 = 0x25,
+		NCCHKey2 = 0x18,
+		NCCHKey3 = 0x1B,
+	};
+
+	class AESEngine {
+	private:
+		constexpr static std::size_t AesKeySlotCount = 0x40;
+
+		std::optional<AESKey> m_generator;
+		std::array<AESKeySlot, AesKeySlotCount> m_slots;
+
+		constexpr void updateNormalKey(std::size_t slotId) {
+			if (m_generator.has_value() && hasKeyX(slotId) && hasKeyY(slotId)) {
+				auto &keySlot = m_slots.at(slotId);
+				AESKey keyX = keySlot.keyX.value();
+				AESKey keyY = keySlot.keyY.value();
+
+				keySlot.normalKey = rolArray(addArray(xorArray(rolArray(keyX, 2), keyY), m_generator.value()), 87);
+			}
+		}
+
+	public:
+		AESEngine() {}
+
+		void loadKeys(const std::filesystem::path& path);
+
+		constexpr bool hasKeyX(std::size_t slotId) {
+			if (slotId >= AesKeySlotCount) {
+				return false;
+			}
+
+			return m_slots.at(slotId).keyX.has_value();
+		}
+
+		constexpr AESKey getKeyX(std::size_t slotId) {
+			return m_slots.at(slotId).keyX.value_or(AESKey{});
+		}
+
+		constexpr void setKeyX(std::size_t slotId, const AESKey &key) {
+			if (slotId < AesKeySlotCount) {
+				m_slots.at(slotId).keyX = key;
+
+				updateNormalKey(slotId);
+			}
+		}
+
+		constexpr bool hasKeyY(std::size_t slotId) {
+			if (slotId >= AesKeySlotCount) {
+				return false;
+			}
+
+			return m_slots.at(slotId).keyY.has_value();
+		}
+
+		constexpr AESKey getKeyY(std::size_t slotId) {
+			return m_slots.at(slotId).keyY.value_or(AESKey{});
+		}
+
+		constexpr void setKeyY(std::size_t slotId, const AESKey &key) {
+			if (slotId < AesKeySlotCount) {
+				m_slots.at(slotId).keyY = key;
+
+				updateNormalKey(slotId);
+			}
+		}
+
+		constexpr bool hasNormalKey(std::size_t slotId) {
+			if (slotId >= AesKeySlotCount) {
+				return false;
+			}
+
+			return m_slots.at(slotId).normalKey.has_value();
+		}
+
+		constexpr AESKey getNormalKey(std::size_t slotId) {
+			return m_slots.at(slotId).normalKey.value_or(AESKey{});
+		}
+
+		constexpr void setNormalKey(std::size_t slotId, const AESKey &key) {
+			if (slotId < AesKeySlotCount) {
+				m_slots.at(slotId).normalKey = key;
+			}
+		}
+	};
+}