mirror of
https://github.com/RetroDECK/Supermodel.git
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124 lines
3.1 KiB
C++
124 lines
3.1 KiB
C++
/**
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** Supermodel
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** A Sega Model 3 Arcade Emulator.
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** Copyright 2011-2016 Bart Trzynadlowski, Nik Henson
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**
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** This file is part of Supermodel.
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**
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** Supermodel is free software: you can redistribute it and/or modify it under
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** the terms of the GNU General Public License as published by the Free
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** Software Foundation, either version 3 of the License, or (at your option)
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** any later version.
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**
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** Supermodel is distributed in the hope that it will be useful, but WITHOUT
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** ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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** FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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** more details.
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**
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** You should have received a copy of the GNU General Public License along
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** with Supermodel. If not, see <http://www.gnu.org/licenses/>.
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**/
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/*
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* Crypto.h
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*
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* Header file for security board encryption device. This code was taken from
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* MAME (http://mamedev.org).
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*/
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// license:BSD-3-Clause
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// copyright-holders:David Haywood
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#pragma once
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#ifndef __SEGA315_5881_CRYPT__
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#define __SEGA315_5881_CRYPT__
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#include <cstdint>
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#include <memory>
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#include <functional>
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class CBlockFile;
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class CCrypto
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{
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public:
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// construction/destruction
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CCrypto();
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void SaveState(CBlockFile *SaveState);
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void LoadState(CBlockFile *SaveState);
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void Init(uint32_t encryptionKey, std::function<uint16_t(uint32_t)> ReadRAMCallback);
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void Reset();
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uint16_t Decrypt(uint8_t **base);
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void SetAddressLow(uint16_t data);
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void SetAddressHigh(uint16_t data);
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void SetSubKey(uint16_t data);
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std::function<uint16_t(uint32_t)> m_read;
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/*
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static void set_read_cb(device_t &device,sega_m2_read_delegate readcb)
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{
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sega_315_5881_crypt_device &dev = downcast<sega_315_5881_crypt_device &>(device);
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dev.m_read = readcb;
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}
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*/
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private:
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uint32_t key;
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std::unique_ptr<uint8_t[]> buffer;
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std::unique_ptr<uint8_t[]> line_buffer;
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std::unique_ptr<uint8_t[]> line_buffer_prev;
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uint32_t prot_cur_address;
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uint16_t subkey, dec_hist;
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uint32_t dec_header;
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bool enc_ready;
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int buffer_pos, line_buffer_pos, line_buffer_size, buffer_bit, buffer_bit2;
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uint8_t buffer2[2];
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uint16_t buffer2a;
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int block_size;
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int block_pos;
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int block_numlines;
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int done_compression;
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struct sbox {
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uint8_t table[64];
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int inputs[6]; // positions of the inputs bits, -1 means no input except from key
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int outputs[2]; // positions of the output bits
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};
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static const sbox fn1_sboxes[4][4];
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static const sbox fn2_sboxes[4][4];
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static const int FN1GK = 38;
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static const int FN2GK = 32;
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static const int fn1_game_key_scheduling[FN1GK][2];
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static const int fn2_game_key_scheduling[FN2GK][2];
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static const int fn1_sequence_key_scheduling[20][2];
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static const int fn2_sequence_key_scheduling[16];
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static const int fn2_middle_result_scheduling[16];
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static const uint8_t trees[9][2][32];
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int feistel_function(int input, const struct sbox *sboxes, uint32_t subkeys);
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uint16_t block_decrypt(uint32_t game_key, uint16_t sequence_key, uint16_t counter, uint16_t data);
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uint16_t get_decrypted_16();
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int get_compressed_bit();
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void enc_start();
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void enc_fill();
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void line_fill();
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};
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#endif
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