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// Copyright 2022 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <array>
#include <vector>
#include "core/hle/service/nfc/nfc_types.h"
namespace CryptoPP {
class SHA256;
template <class T>
class HMAC;
} // namespace CryptoPP
namespace HW::AES {
struct NfcSecret;
} // namespace HW::AES
namespace Service::NFC::AmiiboCrypto {
// Byte locations in Service::NFC::NTAG215File
constexpr std::size_t HMAC_DATA_START = 0x8;
constexpr std::size_t SETTINGS_START = 0x2c;
constexpr std::size_t WRITE_COUNTER_START = 0x29;
constexpr std::size_t HMAC_TAG_START = 0x1B4;
constexpr std::size_t UUID_START = 0x1D4;
constexpr std::size_t DYNAMIC_LOCK_START = 0x208;
using DrgbOutput = std::array<u8, 0x20>;
struct HashSeed {
u16_be magic;
std::array<u8, 0xE> padding;
UniqueSerialNumber uid_1;
u8 nintendo_id_1;
UniqueSerialNumber uid_2;
u8 nintendo_id_2;
std::array<u8, 0x20> keygen_salt;
};
static_assert(sizeof(HashSeed) == 0x40, "HashSeed is an invalid size");
struct CryptoCtx {
std::array<char, 480> buffer;
bool used;
std::size_t buffer_size;
s16 counter;
};
struct DerivedKeys {
std::array<u8, 0x10> aes_key;
std::array<u8, 0x10> aes_iv;
std::array<u8, 0x10> hmac_key;
};
static_assert(sizeof(DerivedKeys) == 0x30, "DerivedKeys is an invalid size");
/// Validates that the amiibo file is not corrupted
bool IsAmiiboValid(const EncryptedNTAG215File& ntag_file);
/// Validates that the amiibo file is not corrupted
bool IsAmiiboValid(const NTAG215File& ntag_file);
/// Converts from encrypted file format to encoded file format
NTAG215File NfcDataToEncodedData(const EncryptedNTAG215File& nfc_data);
/// Converts from encoded file format to encrypted file format
EncryptedNTAG215File EncodedDataToNfcData(const NTAG215File& encoded_data);
// Generates Seed needed for key derivation
HashSeed GetSeed(const NTAG215File& data);
// Middle step on the generation of derived keys
std::vector<u8> GenerateInternalKey(const HW::AES::NfcSecret& secret, const HashSeed& seed);
// Initializes mbedtls context
void CryptoInit(CryptoCtx& ctx, CryptoPP::HMAC<CryptoPP::SHA256>& hmac_ctx,
std::span<const u8> hmac_key, std::span<const u8> seed);
// Feeds data to mbedtls context to generate the derived key
void CryptoStep(CryptoCtx& ctx, CryptoPP::HMAC<CryptoPP::SHA256>& hmac_ctx, DrgbOutput& output);
// Generates the derived key from amiibo data
DerivedKeys GenerateKey(const HW::AES::NfcSecret& secret, const NTAG215File& data);
// Encodes or decodes amiibo data
void Cipher(const DerivedKeys& keys, const NTAG215File& in_data, NTAG215File& out_data);
/// Decodes encripted amiibo data returns true if output is valid
bool DecodeAmiibo(const EncryptedNTAG215File& encrypted_tag_data, NTAG215File& tag_data);
/// Encodes plain amiibo data returns true if output is valid
bool EncodeAmiibo(const NTAG215File& tag_data, EncryptedNTAG215File& encrypted_tag_data);
} // namespace Service::NFC::AmiiboCrypto
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