/*
 * Canon Firmware Decrypter
 * Copyright Alex Bernstein, 2003
 */
#include <stdio.h>
#include <stddef.h>

char crypt1[] = {
0x41, 0xCA, 0x42, 0xF9, 0x3C, 0x6D, 0x9D, 0xDF, 0xD8, 0x19, 0x84, 0x08, 0x50, 0xFB, 0x67, 0xA1,
0xAD, 0x35, 0xF2, 0xCE, 0xDF, 0x9A, 0xF3, 0xC4, 0xF5, 0x22, 0x1A, 0x8A, 0xD5, 0x64, 0x08, 0x65,
0xD3, 0x2C, 0x96, 0xB6, 0x08, 0x11, 0x3A, 0xB3, 0x90, 0x08, 0xE6, 0x2E, 0x88, 0xED, 0x24, 0xFB,
0x24, 0x28, 0x82, 0x3D, 0x39, 0xA8, 0xF3, 0x52, 0x98, 0xF9, 0xA7, 0x75, 0x52, 0x63, 0x0A, 0xF9,
0xED, 0x7A, 0x82, 0x02, 0x1F, 0x94, 0x76, 0xE1, 0xBA, 0xB6, 0xB9, 0x7B, 0x6C, 0xA2, 0xDA, 0x16,
0x5B, 0x58, 0x51, 0x20, 0xBC, 0xF1, 0xD8, 0x34, 0x36, 0xAA, 0xD1, 0xA5, 0xEF, 0xF4, 0xE8, 0x50,
0xDD, 0x09, 0x95, 0x8D, 0xC9, 0x06, 0x8D, 0xF0, 0x2D, 0xA2, 0xF1, 0x0D, 0x5E, 0x14, 0x09, 0x10,
0x3E, 0x9E, 0x58, 0xCA, 0x39, 0xAB, 0x11, 0x4F, 0x7F, 0x08, 0x8B, 0xCC, 0x4D, 0x9E, 0xD7, 0x20,
0x1D, 0x8F, 0xCA, 0x46, 0xAE, 0x17, 0xB5, 0x6B, 0xE6, 0x0A, 0xE9, 0x9A, 0x6E, 0x4A, 0x4C, 0xCC,
0xA6, 0xEB, 0xD8, 0x2B, 0xF1, 0xB0, 0x2F, 0xFB, 0x5F, 0xF7, 0x57, 0x06, 0xB3, 0x77, 0xFC, 0x1B,
0x98, 0xD9, 0xBA, 0x5A, 0x5F, 0xA4, 0xE0, 0x1F, 0x74, 0x99, 0xF1, 0x69, 0xA3, 0x8A, 0x43, 0x99,
0xCE, 0x77, 0x04, 0xCC, 0x47, 0x7D, 0xCB, 0x39, 0x6E, 0x2D, 0x5A, 0x59, 0xE4, 0x92, 0x91, 0x37,
0x1D, 0x60, 0xAA, 0xE5, 0x4F, 0xF8, 0xFA, 0xC1, 0x59, 0x52, 0x2C, 0xAB, 0x09, 0x0F, 0xEE, 0x5E,
0x5B, 0xC0, 0x64, 0xB3, 0xF5, 0xC2, 0xD3, 0xCC, 0x1E, 0x2C, 0xB4, 0x0B, 0xA8, 0xBF, 0x40, 0x77,
0x08, 0xA0, 0xC9, 0x93, 0xDF, 0xA8, 0x79, 0x28, 0x41, 0x93, 0x37, 0x2B, 0xF7, 0xD4, 0xAD, 0x1B,
0x18, 0x9E, 0xE0, 0xB4, 0x59, 0x60, 0x58, 0xEA, 0xAB, 0x2A, 0x6C, 0xD4, 0x07, 0xEE, 0xEF, 0x18,
0x65, 0xFF, 0x7F, 0x6F, 0x1E, 0xDE, 0xF3, 0x83, 0xF4, 0xB6, 0xF8, 0x7E, 0x0E, 0xBD, 0xB3, 0x6A,
0x91, 0x5D, 0x24, 0x9F, 0x97, 0x74, 0x60, 0xD6, 0xC9, 0xE2, 0xA6, 0x54, 0x49, 0xE8, 0xB2, 0x6B,
0x4E, 0xBD, 0x41, 0x2C, 0xC9, 0x40, 0xCF, 0x85, 0x0A, 0xCA, 0x8E, 0x67, 0x99, 0x43, 0x2C, 0x9A,
0x56, 0x3E, 0x26, 0x23, 0x80, 0xA5, 0x27, 0xD9, 0x05, 0xD4, 0x82, 0x6E, 0x65, 0xE9, 0x81, 0x4E,
0xB9, 0x58, 0xE3, 0x3F, 0x6A, 0xEA, 0x5C, 0xE7, 0x83, 0x13, 0x2A, 0x63, 0x59, 0x60, 0x24, 0x7A,
0x0C, 0x6D, 0x79, 0x80, 0x13, 0xED, 0x25, 0xA2, 0x50, 0x15, 0x4B, 0xB3, 0x03, 0x62, 0x33, 0xF5,
0x60, 0x9D, 0x3F, 0xC5, 0xE2, 0xB7, 0xC8, 0xAF, 0xC8, 0xEB, 0x81, 0x76, 0x8C, 0x9D, 0xE9, 0x62,
0xDA, 0x13, 0x99, 0x3B, 0xA5, 0xDE, 0x84, 0xD3, 0x20, 0x24, 0x5C, 0xAB, 0xD9, 0xCB, 0x63, 0xFB,
0x16, 0x39, 0xB7, 0xB3, 0x91, 0xD3, 0xD3, 0xA8, 0x42, 0xA0, 0xE3, 0x27, 0xE8, 0x45, 0x74, 0xD8,
0x24, 0xEC, 0xE2, 0xFE, 0x3B, 0x73, 0xF5, 0xDC, 0xBE, 0xB2, 0xED, 0xE6, 0xAD, 0x96, 0xBB, 0x23,
0xD6, 0x7F, 0x32, 0x03, 0x71, 0xD0, 0x33, 0x85, 0xC1, 0x86, 0x80, 0xE4, 0x07, 0x3F, 0xF1, 0x79,
0x85, 0xC1, 0xB9, 0xCB, 0x36, 0x8C, 0x9A, 0x01, 0xAD, 0x1E, 0xA2, 0xF1, 0x16, 0x45, 0x50, 0x30,
0xE9, 0x52, 0x4A, 0x80, 0x88, 0xA7, 0x80, 0x27, 0x03, 0x3E, 0xF3, 0x1D, 0xD7, 0x86, 0x4B, 0xF1,
0x9D, 0x69, 0x45, 0xE0, 0xD4, 0x31, 0x89, 0xDC, 0x47, 0x45, 0x94, 0xC5, 0x4D, 0x20, 0x22, 0xB4,
0xAB, 0x71, 0x36, 0x6B, 0xBC, 0xAF, 0x74, 0x20, 0x0E, 0x6B, 0xB0, 0xB8, 0xB5, 0xF0, 0x34, 0xCA,
0x02, 0xAD, 0x7B, 0x35, 0x3D, 0x50, 0x01, 0x9E, 0x30, 0x7B, 0x69, 0x2F, 0x6A, 0x79, 0xF4, 0xEF
};

char crypt2[] = {
0xA5, 0xF5, 0x2A, 0xBE, 0x62, 0x66, 0x1C, 0x80, 0x87, 0x3F, 0x91, 0x01, 0x6E, 0xBC, 0x87, 0x02,
0xD0, 0x2A, 0x3A, 0xC4, 0x65, 0x3C, 0x91, 0x35, 0xB5, 0xAE, 0x21, 0x21, 0xF5, 0x3F, 0xAC, 0x1F,
0xBE, 0x92, 0xA6, 0xF2, 0xA8, 0x42, 0x39, 0x8F, 0x41, 0x95, 0x91, 0xBD, 0x4C, 0xAD, 0x85, 0xC7,
0xB7, 0xD6, 0xAE, 0x1C, 0xE2, 0x62, 0xEB, 0xC2, 0x03, 0x5D, 0xD6, 0x4E, 0x7B, 0x59, 0x0F, 0xDD,
0xB7, 0x3E, 0x22, 0x55, 0x45, 0x91, 0x81, 0x71, 0x71, 0x9F, 0xE8, 0x6D, 0x67, 0x40, 0x8C, 0x43,
0x30, 0xAA, 0x43, 0x39, 0x3C, 0x35, 0x4E, 0xAF, 0x67, 0x50, 0xDA, 0xE5, 0xA3, 0xA8, 0x08, 0x9C,
0x59, 0x3E, 0xEB, 0xD0, 0x01, 0xFB, 0xE5, 0x15, 0x59, 0xFF, 0x76, 0xD7, 0x10, 0x39, 0x88, 0x41,
0x85, 0xE1, 0xF4, 0x43, 0xE3, 0x66, 0xFE, 0x29, 0x7E, 0x50, 0xD4, 0x82, 0x0F, 0x17, 0x38, 0x10,
0x45, 0x54, 0x3A, 0x53, 0xF8, 0x1C, 0xA1, 0x08, 0x5B, 0x60, 0x25, 0xCA, 0xF7, 0xE7, 0x35, 0x3F,
0xC3, 0xF9, 0x02, 0x58, 0x14, 0xE6, 0x71, 0x16, 0x03, 0x1C, 0x8E, 0x0F, 0x34, 0xFE, 0xF5, 0x0A,
0x31, 0x03, 0x49, 0x41, 0x07, 0xB3, 0x63, 0x21, 0xED, 0x5B, 0x40, 0xF2, 0xE2, 0x24, 0x14, 0x63,
0x8B, 0x45, 0x9D, 0xA0, 0x65, 0x7A, 0xCE, 0xDF, 0x90, 0xD6, 0xC5, 0x7B, 0x26, 0xE3, 0x38, 0xF1,
0x31, 0x62, 0xB9, 0x60, 0xE7, 0x02, 0x23, 0xEE, 0x10, 0x44, 0x2B, 0x1B, 0x46, 0x07, 0x87, 0x04,
0xD5, 0xB2, 0x33, 0x8B, 0x97, 0x75, 0xD7, 0x0F, 0x07, 0xB7, 0xBB, 0x83, 0xC8, 0x3E, 0xDA, 0xF4,
0x5C, 0x70, 0x4D, 0xDF, 0x70, 0x43, 0xF4, 0x15, 0x6D, 0x6C, 0xB2, 0x59, 0x77, 0xEA, 0xB5, 0x86,
0x4B, 0xF7, 0x95, 0x80, 0x2A, 0x74, 0x37, 0x04, 0x50, 0x94, 0xF4, 0x92, 0x6D, 0x45, 0x73, 0x49,
0x90, 0xA8, 0x22, 0x03, 0xB8, 0x0A, 0x22, 0x2D, 0xBB, 0xAD, 0xDF, 0x54, 0xB5, 0x3D, 0xB7, 0x8C,
0xDE, 0xE6, 0x2A, 0x7D, 0x31, 0xEB, 0x7E, 0x82, 0xFF, 0x1D, 0xFF, 0xF7, 0x70, 0xE6, 0x57, 0xAC,
0x34, 0x40, 0x55, 0xEC, 0x75, 0x77, 0x03, 0xF2, 0x29, 0xD5, 0x4C, 0x75, 0xB8, 0xF7, 0x5B, 0x91,
0x75, 0x8C, 0x54, 0xF3, 0xCB, 0x36, 0xBB, 0xA4, 0xF6, 0x83, 0xD4, 0x74, 0xE4, 0xA8, 0x57, 0xB0,
0x2B, 0x95, 0x5E, 0x18, 0xFE, 0x66, 0xC1, 0x11, 0xF6, 0xCE, 0xAE, 0xBB, 0x93, 0xE6, 0x8B, 0xAB,
0x61, 0xFC, 0x93, 0x56, 0xDA, 0x4F, 0x66, 0x12, 0xF1, 0x6A, 0x07, 0xDD, 0x6F, 0x6D, 0xBE, 0x76,
0xC9, 0xA3, 0xCB, 0xB9, 0x96, 0xB7, 0x57, 0x70, 0x09, 0x3C, 0xE1, 0x93, 0xE9, 0xD3, 0x54, 0x1C,
0xAA, 0xC4, 0xD1, 0x75, 0xC2, 0x99, 0x12, 0x12, 0xCA, 0x50, 0xB5, 0x32, 0xC7, 0x85, 0x75, 0x3E,
0xD3, 0x08, 0x75, 0xEF, 0x25, 0xF8, 0xB5, 0xED, 0xB1, 0xC0, 0xD7, 0x25, 0xFB, 0x8A, 0x23, 0xEB,
0xA0, 0xC1, 0x03, 0x0D, 0xFC, 0x1B, 0xAB, 0x89, 0xAA, 0x6B, 0x76, 0xC4, 0x31, 0x45, 0xA9, 0x1D,
0x65, 0x3F, 0xFD, 0x08, 0x69, 0x34, 0x15, 0x13, 0x16, 0x42, 0x03, 0x6E, 0x81, 0x36, 0x97, 0x5F,
0x93, 0x22, 0xFA, 0x50, 0x1F, 0x13, 0x82, 0x61, 0x78, 0xEA, 0x28, 0xD5, 0x68, 0x96, 0xA9, 0x63,
0x55, 0x98, 0x2F, 0x24, 0xFB, 0x42, 0x76, 0xF9, 0x1F, 0xBF, 0x79, 0x28, 0x22, 0xC7, 0xC1, 0x17,
0x36, 0x1D, 0xC0, 0xB5, 0x51, 0x42, 0x6D, 0x52, 0x3D, 0x56, 0x8C, 0x67, 0x25, 0xC8, 0x02, 0x04,
0x26, 0xE2, 0xBC, 0x47, 0xD1, 0x5A, 0xB7, 0x99, 0xC2, 0x8E, 0x01, 0x2D, 0xC2, 0xFE, 0xF0, 0x02,
0x4E, 0x94, 0x80, 0x14, 0x20, 0xF0, 0x55, 0xD4, 0x58, 0x93, 0x9E, 0x33, 0x5B, 0xA5, 0xE6, 0xC6,
0x88};

#define CRYPT1_SIZE (sizeof(crypt1)/sizeof(crypt1[0]))
#define CRYPT2_SIZE (sizeof(crypt2)/sizeof(crypt2[0]))

int main(int argc, char *argv[])
{
  FILE *in;
  FILE *out;
  int i = 0, j = 0, val;

  if (argc != 3) {
    printf("Usage: decrypt inputfile outfile\n");
    return -1;
  }

  if ((in = fopen(argv[1], "r")) == NULL) {
    printf("Cant't open file name %s\n", argv[1]);
    return -1;
  }

  if ((out = fopen(argv[2], "w")) == NULL) {
    printf("Cant't open file name %s\n", argv[2]);
    fclose(in);
    return -1;
  }

  while ((val = fgetc(in)) != EOF) {
    fputc(val ^ crypt1[i] ^ crypt2[j], out);
    i++;
    j++;
    if (i >= CRYPT1_SIZE) i=0;
    if (j >= CRYPT2_SIZE) j=0;
  }
  fclose(out);
}