GSAcrypt - Gameboy Advance AR Crypto Program by Parasyte

GSAcrypt.c

/* GSAcrypt - Gameboy Advance AR Crypto Program
 *
 * Copyright notice for this file:
 *  Copyright (C) 2001-2003 Parasyte
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

typedef unsigned int u32;
typedef unsigned short u16;
typedef unsigned char u8;


u32 seeds[4];
u8 v3enc;

//seed tables for AR v1
u8 v1_deadtable1[256] = {
   0x31, 0x1C, 0x23, 0xE5, 0x89, 0x8E, 0xA1, 0x37, 0x74, 0x6D, 0x67, 0xFC, 0x1F, 0xC0, 0xB1, 0x94,
   0x3B, 0x05, 0x56, 0x86, 0x00, 0x24, 0xF0, 0x17, 0x72, 0xA2, 0x3D, 0x1B, 0xE3, 0x17, 0xC5, 0x0B,
   0xB9, 0xE2, 0xBD, 0x58, 0x71, 0x1B, 0x2C, 0xFF, 0xE4, 0xC9, 0x4C, 0x5E, 0xC9, 0x55, 0x33, 0x45,
   0x7C, 0x3F, 0xB2, 0x51, 0xFE, 0x10, 0x7E, 0x75, 0x3C, 0x90, 0x8D, 0xDA, 0x94, 0x38, 0xC3, 0xE9,
   0x95, 0xEA, 0xCE, 0xA6, 0x06, 0xE0, 0x4F, 0x3F, 0x2A, 0xE3, 0x3A, 0xE4, 0x43, 0xBD, 0x7F, 0xDA,
   0x55, 0xF0, 0xEA, 0xCB, 0x2C, 0xA8, 0x47, 0x61, 0xA0, 0xEF, 0xCB, 0x13, 0x18, 0x20, 0xAF, 0x3E,
   0x4D, 0x9E, 0x1E, 0x77, 0x51, 0xC5, 0x51, 0x20, 0xCF, 0x21, 0xF9, 0x39, 0x94, 0xDE, 0xDD, 0x79,
   0x4E, 0x80, 0xC4, 0x9D, 0x94, 0xD5, 0x95, 0x01, 0x27, 0x27, 0xBD, 0x6D, 0x78, 0xB5, 0xD1, 0x31,
   0x6A, 0x65, 0x74, 0x74, 0x58, 0xB3, 0x7C, 0xC9, 0x5A, 0xED, 0x50, 0x03, 0xC4, 0xA2, 0x94, 0x4B,
   0xF0, 0x58, 0x09, 0x6F, 0x3E, 0x7D, 0xAE, 0x7D, 0x58, 0xA0, 0x2C, 0x91, 0xBB, 0xE1, 0x70, 0xEB,
   0x73, 0xA6, 0x9A, 0x44, 0x25, 0x90, 0x16, 0x62, 0x53, 0xAE, 0x08, 0xEB, 0xDC, 0xF0, 0xEE, 0x77,
   0xC2, 0xDE, 0x81, 0xE8, 0x30, 0x89, 0xDB, 0xFE, 0xBC, 0xC2, 0xDF, 0x26, 0xE9, 0x8B, 0xD6, 0x93,
   0xF0, 0xCB, 0x56, 0x90, 0xC0, 0x46, 0x68, 0x15, 0x43, 0xCB, 0xE9, 0x98, 0xE3, 0xAF, 0x31, 0x25,
   0x4D, 0x7B, 0xF3, 0xB1, 0x74, 0xE2, 0x64, 0xAC, 0xD9, 0xF6, 0xA0, 0xD5, 0x0B, 0x9B, 0x49, 0x52,
   0x69, 0x3B, 0x71, 0x00, 0x2F, 0xBB, 0xBA, 0x08, 0xB1, 0xAE, 0xBB, 0xB3, 0xE1, 0xC9, 0xA6, 0x7F,
   0x17, 0x97, 0x28, 0x72, 0x12, 0x6E, 0x91, 0xAE, 0x3A, 0xA2, 0x35, 0x46, 0x27, 0xF8, 0x12, 0x50
};
u8 v1_deadtable2[256] = {
   0xD8, 0x65, 0x04, 0xC2, 0x65, 0xD5, 0xB0, 0x0C, 0xDF, 0x9D, 0xF0, 0xC3, 0x9A, 0x17, 0xC9, 0xA6,
   0xE1, 0xAC, 0x0D, 0x14, 0x2F, 0x3C, 0x2C, 0x87, 0xA2, 0xBF, 0x4D, 0x5F, 0xAC, 0x2D, 0x9D, 0xE1,
   0x0C, 0x9C, 0xE7, 0x7F, 0xFC, 0xA8, 0x66, 0x59, 0xAC, 0x18, 0xD7, 0x05, 0xF0, 0xBF, 0xD1, 0x8B,
   0x35, 0x9F, 0x59, 0xB4, 0xBA, 0x55, 0xB2, 0x85, 0xFD, 0xB1, 0x72, 0x06, 0x73, 0xA4, 0xDB, 0x48,
   0x7B, 0x5F, 0x67, 0xA5, 0x95, 0xB9, 0xA5, 0x4A, 0xCF, 0xD1, 0x44, 0xF3, 0x81, 0xF5, 0x6D, 0xF6,
   0x3A, 0xC3, 0x57, 0x83, 0xFA, 0x8E, 0x15, 0x2A, 0xA2, 0x04, 0xB2, 0x9D, 0xA8, 0x0D, 0x7F, 0xB8,
   0x0F, 0xF6, 0xAC, 0xBE, 0x97, 0xCE, 0x16, 0xE6, 0x31, 0x10, 0x60, 0x16, 0xB5, 0x83, 0x45, 0xEE,
   0xD7, 0x5F, 0x2C, 0x08, 0x58, 0xB1, 0xFD, 0x7E, 0x79, 0x00, 0x34, 0xAD, 0xB5, 0x31, 0x34, 0x39,
   0xAF, 0xA8, 0xDD, 0x52, 0x6A, 0xB0, 0x60, 0x35, 0xB8, 0x1D, 0x52, 0xF5, 0xF5, 0x30, 0x00, 0x7B,
   0xF4, 0xBA, 0x03, 0xCB, 0x3A, 0x84, 0x14, 0x8A, 0x6A, 0xEF, 0x21, 0xBD, 0x01, 0xD8, 0xA0, 0xD4,
   0x43, 0xBE, 0x23, 0xE7, 0x76, 0x27, 0x2C, 0x3F, 0x4D, 0x3F, 0x43, 0x18, 0xA7, 0xC3, 0x47, 0xA5,
   0x7A, 0x1D, 0x02, 0x55, 0x09, 0xD1, 0xFF, 0x55, 0x5E, 0x17, 0xA0, 0x56, 0xF4, 0xC9, 0x6B, 0x90,
   0xB4, 0x80, 0xA5, 0x07, 0x22, 0xFB, 0x22, 0x0D, 0xD9, 0xC0, 0x5B, 0x08, 0x35, 0x05, 0xC1, 0x75,
   0x4F, 0xD0, 0x51, 0x2D, 0x2E, 0x5E, 0x69, 0xE7, 0x3B, 0xC2, 0xDA, 0xFF, 0xF6, 0xCE, 0x3E, 0x76,
   0xE8, 0x36, 0x8C, 0x39, 0xD8, 0xF3, 0xE9, 0xA6, 0x42, 0xE6, 0xC1, 0x4C, 0x05, 0xBE, 0x17, 0xF2,
   0x5C, 0x1B, 0x19, 0xDB, 0x0F, 0xF3, 0xF8, 0x49, 0xEB, 0x36, 0xF6, 0x40, 0x6F, 0xAD, 0xC1, 0x8C
};


//seed tables for AR v3
u8 v3_deadtable1[256] = {
   0xD0, 0xFF, 0xBA, 0xE5, 0xC1, 0xC7, 0xDB, 0x5B, 0x16, 0xE3, 0x6E, 0x26, 0x62, 0x31, 0x2E, 0x2A,
   0xD1, 0xBB, 0x4A, 0xE6, 0xAE, 0x2F, 0x0A, 0x90, 0x29, 0x90, 0xB6, 0x67, 0x58, 0x2A, 0xB4, 0x45,
   0x7B, 0xCB, 0xF0, 0x73, 0x84, 0x30, 0x81, 0xC2, 0xD7, 0xBE, 0x89, 0xD7, 0x4E, 0x73, 0x5C, 0xC7,
   0x80, 0x1B, 0xE5, 0xE4, 0x43, 0xC7, 0x46, 0xD6, 0x6F, 0x7B, 0xBF, 0xED, 0xE5, 0x27, 0xD1, 0xB5,
   0xD0, 0xD8, 0xA3, 0xCB, 0x2B, 0x30, 0xA4, 0xF0, 0x84, 0x14, 0x72, 0x5C, 0xFF, 0xA4, 0xFB, 0x54,
   0x9D, 0x70, 0xE2, 0xFF, 0xBE, 0xE8, 0x24, 0x76, 0xE5, 0x15, 0xFB, 0x1A, 0xBC, 0x87, 0x02, 0x2A,
   0x58, 0x8F, 0x9A, 0x95, 0xBD, 0xAE, 0x8D, 0x0C, 0xA5, 0x4C, 0xF2, 0x5C, 0x7D, 0xAD, 0x51, 0xFB,
   0xB1, 0x22, 0x07, 0xE0, 0x29, 0x7C, 0xEB, 0x98, 0x14, 0xC6, 0x31, 0x97, 0xE4, 0x34, 0x8F, 0xCC,
   0x99, 0x56, 0x9F, 0x78, 0x43, 0x91, 0x85, 0x3F, 0xC2, 0xD0, 0xD1, 0x80, 0xD1, 0x77, 0xA7, 0xE2,
   0x43, 0x99, 0x1D, 0x2F, 0x8B, 0x6A, 0xE4, 0x66, 0x82, 0xF7, 0x2B, 0x0B, 0x65, 0x14, 0xC0, 0xC2,
   0x1D, 0x96, 0x78, 0x1C, 0xC4, 0xC3, 0xD2, 0xB1, 0x64, 0x07, 0xD7, 0x6F, 0x02, 0xE9, 0x44, 0x31,
   0xDB, 0x3C, 0xEB, 0x93, 0xED, 0x9A, 0x57, 0x05, 0xB9, 0x0E, 0xAF, 0x1F, 0x48, 0x11, 0xDC, 0x35,
   0x6C, 0xB8, 0xEE, 0x2A, 0x48, 0x2B, 0xBC, 0x89, 0x12, 0x59, 0xCB, 0xD1, 0x18, 0xEA, 0x72, 0x11,
   0x01, 0x75, 0x3B, 0xB5, 0x56, 0xF4, 0x8B, 0xA0, 0x41, 0x75, 0x86, 0x7B, 0x94, 0x12, 0x2D, 0x4C,
   0x0C, 0x22, 0xC9, 0x4A, 0xD8, 0xB1, 0x8D, 0xF0, 0x55, 0x2E, 0x77, 0x50, 0x1C, 0x64, 0x77, 0xAA,
   0x3E, 0xAC, 0xD3, 0x3D, 0xCE, 0x60, 0xCA, 0x5D, 0xA0, 0x92, 0x78, 0xC6, 0x51, 0xFE, 0xF9, 0x30
};
u8 v3_deadtable2[256] = {
   0xAA, 0xAF, 0xF0, 0x72, 0x90, 0xF7, 0x71, 0x27, 0x06, 0x11, 0xEB, 0x9C, 0x37, 0x12, 0x72, 0xAA,
   0x65, 0xBC, 0x0D, 0x4A, 0x76, 0xF6, 0x5C, 0xAA, 0xB0, 0x7A, 0x7D, 0x81, 0xC1, 0xCE, 0x2F, 0x9F,
   0x02, 0x75, 0x38, 0xC8, 0xFC, 0x66, 0x05, 0xC2, 0x2C, 0xBD, 0x91, 0xAD, 0x03, 0xB1, 0x88, 0x93,
   0x31, 0xC6, 0xAB, 0x40, 0x23, 0x43, 0x76, 0x54, 0xCA, 0xE7, 0x00, 0x96, 0x9F, 0xD8, 0x24, 0x8B,
   0xE4, 0xDC, 0xDE, 0x48, 0x2C, 0xCB, 0xF7, 0x84, 0x1D, 0x45, 0xE5, 0xF1, 0x75, 0xA0, 0xED, 0xCD,
   0x4B, 0x24, 0x8A, 0xB3, 0x98, 0x7B, 0x12, 0xB8, 0xF5, 0x63, 0x97, 0xB3, 0xA6, 0xA6, 0x0B, 0xDC,
   0xD8, 0x4C, 0xA8, 0x99, 0x27, 0x0F, 0x8F, 0x94, 0x63, 0x0F, 0xB0, 0x11, 0x94, 0xC7, 0xE9, 0x7F,
   0x3B, 0x40, 0x72, 0x4C, 0xDB, 0x84, 0x78, 0xFE, 0xB8, 0x56, 0x08, 0x80, 0xDF, 0x20, 0x2F, 0xB9,
   0x66, 0x2D, 0x60, 0x63, 0xF5, 0x18, 0x15, 0x1B, 0x86, 0x85, 0xB9, 0xB4, 0x68, 0x0E, 0xC6, 0xD1,
   0x8A, 0x81, 0x2B, 0xB3, 0xF6, 0x48, 0xF0, 0x4F, 0x9C, 0x28, 0x1C, 0xA4, 0x51, 0x2F, 0xD7, 0x4B,
   0x17, 0xE7, 0xCC, 0x50, 0x9F, 0xD0, 0xD1, 0x40, 0x0C, 0x0D, 0xCA, 0x83, 0xFA, 0x5E, 0xCA, 0xEC,
   0xBF, 0x4E, 0x7C, 0x8F, 0xF0, 0xAE, 0xC2, 0xD3, 0x28, 0x41, 0x9B, 0xC8, 0x04, 0xB9, 0x4A, 0xBA,
   0x72, 0xE2, 0xB5, 0x06, 0x2C, 0x1E, 0x0B, 0x2C, 0x7F, 0x11, 0xA9, 0x26, 0x51, 0x9D, 0x3F, 0xF8,
   0x62, 0x11, 0x2E, 0x89, 0xD2, 0x9D, 0x35, 0xB1, 0xE4, 0x0A, 0x4D, 0x93, 0x01, 0xA7, 0xD1, 0x2D,
   0x00, 0x87, 0xE2, 0x2D, 0xA4, 0xE9, 0x0A, 0x06, 0x66, 0xF8, 0x1F, 0x44, 0x75, 0xB5, 0x6B, 0x1C,
   0xFC, 0x31, 0x09, 0x48, 0xA3, 0xFF, 0x92, 0x12, 0x58, 0xE9, 0xFA, 0xAE, 0x4F, 0xE2, 0xB4, 0xCC
};


void decrypt_code(u32 *address, u32 *value);
void encrypt_code(u32 *address, u32 *value);
void deadface(u16 value);
u32 seed_gen(u8 upper, u8 seed, u8 *deadtable1, u8 *deadtable2);


void decrypt_code(u32 *address, u32 *value) {
   int i;
   u32 rollingseed = 0xC6EF3720;

   for (i = 0; i < 32; i++) {
      *value -= ((((*address << 4) + seeds[2]) ^ (*address + rollingseed)) ^ ((*address >> 5) + seeds[3]));
      *address -= ((((*value << 4) + seeds[0]) ^ (*value + rollingseed)) ^ ((*value >> 5) + seeds[1]));
      rollingseed -= 0x9E3779B9;
   }
   if (*address == 0xDEADFACE) deadface(*value);
}

void encrypt_code(u32 *address, u32 *value) {
   int i;
   u32 rollingseed = 0, oldaddr = *address, oldval = *value;

   for (i = 0; i < 32; i++) {
      rollingseed += 0x9E3779B9;
      *address += ((((*value << 4) + seeds[0]) ^ (*value + rollingseed)) ^ ((*value >> 5) + seeds[1]));
      *value += ((((*address << 4) + seeds[2]) ^ (*address + rollingseed)) ^ ((*address >> 5) + seeds[3]));
   }
   if (oldaddr == 0xDEADFACE) deadface(oldval);
}

void deadface(u16 value) {
   int i;
   u8 *deadtable1, *deadtable2;

   if (v3enc) {
      deadtable1 = (u8*)(&v3_deadtable1);
      deadtable2 = (u8*)(&v3_deadtable2);
   }
   else {
      deadtable1 = (u8*)(&v1_deadtable1);
      deadtable2 = (u8*)(&v1_deadtable2);
   }

   for (i = 0; i < 4; i++)
      seeds[i] = seed_gen(((value & 0xFF00) >> 8), (value & 0xFF) + i, deadtable1, deadtable2);
   //printf("Encryption Seeds Have Changed!\n");
}

u32 seed_gen(u8 upper, u8 seed, u8 *deadtable1, u8 *deadtable2) {
   int i;
   u32 newseed;

   for (i = 0; i < 4; i++)
      newseed = ((newseed << 8) | ((deadtable1[(i + upper) & 0xFF] + deadtable2[seed]) & 0xFF));
   return newseed;
}

GSAcrypt.h

// GSACrypt made by Parasyte

// deadface(0) to initialize encryption seeds
// v3enc = 0 to use  AR v1/2 seed tables
// v3enc = 1 to use  AR v3/4 seed tables

typedef unsigned int u32;
typedef unsigned short u16;
typedef unsigned char u8;

u8 v3enc;

void deadface(u16 value);
void decrypt_code(u32 *address, u32 *value);
void encrypt_code(u32 *address, u32 *value);