Алгоритм шифрования Lucifer. Литература

template<typename T>
void Swap(T& arg1, T& arg2) {
  T tmp = arg1;
  arg1 = arg2;
  arg2 = tmp;
}
 
const size_t block_size = 16; // 128 bit
const size_t key_size   = 16; // 128 bit
 
static const unsigned char s0[16] = {
  /*0*/ 0x0C,
  /*1*/ 0x0F,
  /*2*/ 0x07,
  /*3*/ 0x0A,
  /*4*/ 0x0E,
  /*5*/ 0x0D,
  /*6*/ 0x0B,
  /*7*/ 0x00,
  /*8*/ 0x02,
  /*9*/ 0x06,
  /*A*/ 0x03,
  /*B*/ 0x01,
  /*C*/ 0x09,
  /*D*/ 0x04,
  /*E*/ 0x05,
  /*F*/ 0x08
};
 
static const unsigned char s1[16] = {
  /*0*/ 0x07,
  /*1*/ 0x02,
  /*2*/ 0x0E,
  /*3*/ 0x09,
  /*4*/ 0x03,
  /*5*/ 0x0B,
  /*6*/ 0x00,
  /*7*/ 0x04,
  /*8*/ 0x0C,
  /*9*/ 0x0D,
  /*A*/ 0x01,
  /*B*/ 0x0A,
  /*C*/ 0x06,
  /*D*/ 0x0F,
  /*E*/ 0x08,
  /*F*/ 0x05
};
 
static const unsigned char m1[8] = {
  0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01
};
 
static const unsigned char m2[8] = {
  0x7F, 0xBF, 0xDF, 0xEF, 0xF7, 0xFB, 0xFD, 0xFE 
};
 
#define SHIFTLEFT(x, n) (x) << (n)
#define SHIFTRIGHT(x, n) static_cast<unsigned char>(x) >> (n)
 
#define HIGHSUBBYTE(x) SHIFTRIGHT((x), 4)
#define LOWSUBBYTE(x) (x) & 0x0F
 
void Lucifer(char block[block_size], char key[key_size], bool decrypt) {
  char* lower_half = block;
  char* upper_half = block + block_size / 2;
  
  int key_byte_idx = decrypt? 8 : 0;
  
  const int round_count = 16;
  for (int round = 0; round < round_count; ++round) {
    if(decrypt)
      key_byte_idx = (key_byte_idx + 1) % round_count;
    
    int transform_countrol_byte_idx = key_byte_idx;
    
    const int step_count  = 8;
    for (int step = 0; step < step_count; ++step) {
      char message_byte = upper_half[step];
 
      // Confusion
      if (key[transform_countrol_byte_idx] & m1[step_count - step - 1])
        message_byte = SHIFTLEFT(s1[HIGHSUBBYTE(message_byte)], 4) | s0[LOWSUBBYTE(message_byte)];
      else
        message_byte = SHIFTLEFT(s0[HIGHSUBBYTE(message_byte)], 4) | s1[LOWSUBBYTE(message_byte)];
 
      // Key interruption
      message_byte ^= key[key_byte_idx];
 
      // Permutation
      message_byte = SHIFTRIGHT(message_byte & m1[0], 3) |
                     SHIFTRIGHT(message_byte & m1[1], 4) |
                     SHIFTLEFT (message_byte & m1[2], 2) |
                     SHIFTRIGHT(message_byte & m1[3], 1) |
                     SHIFTLEFT (message_byte & m1[4], 2) |
                     SHIFTLEFT (message_byte & m1[5], 4) |
                     SHIFTRIGHT(message_byte & m1[6], 1) |
                     SHIFTLEFT (message_byte & m1[7], 1);
 
      // Diffusion
      lower_half[(7 + step) % step_count] = ((message_byte ^ lower_half[(7 + step) % step_count]) & m1[0]) | (lower_half[(7 + step) % step_count] & m2[0]);
      lower_half[(6 + step) % step_count] = ((message_byte ^ lower_half[(6 + step) % step_count]) & m1[1]) | (lower_half[(6 + step) % step_count] & m2[1]);
      lower_half[(2 + step) % step_count] = ((message_byte ^ lower_half[(2 + step) % step_count]) & m1[2]) | (lower_half[(2 + step) % step_count] & m2[2]);
      lower_half[(1 + step) % step_count] = ((message_byte ^ lower_half[(1 + step) % step_count]) & m1[3]) | (lower_half[(1 + step) % step_count] & m2[3]);
      lower_half[(5 + step) % step_count] = ((message_byte ^ lower_half[(5 + step) % step_count]) & m1[4]) | (lower_half[(5 + step) % step_count] & m2[4]);
      lower_half[(0 + step) % step_count] = ((message_byte ^ lower_half[(0 + step) % step_count]) & m1[5]) | (lower_half[(0 + step) % step_count] & m2[5]);
      lower_half[(3 + step) % step_count] = ((message_byte ^ lower_half[(3 + step) % step_count]) & m1[6]) | (lower_half[(3 + step) % step_count] & m2[6]);
      lower_half[(4 + step) % step_count] = ((message_byte ^ lower_half[(4 + step) % step_count]) & m1[7]) | (lower_half[(4 + step) % step_count] & m2[7]);
      
      if (step < step_count - 1 || decrypt)
        key_byte_idx = (key_byte_idx + 1) % round_count;
    }
 
    // Swap halves
    Swap(lower_half, upper_half);
  }
 
  // Physically swap halves
  for (int i = 0; i < block_size / 2; ++i)
    Swap(block[i], block[i + block_size / 2]);
}

int main(int argc, char* argv[])
{
  char crypt[block_size]="1234567890ABCDEF";
  char key[block_size]="1236565748484857";
  bool check = false;
   Lucifer(crypt, key, check);
 
FILE *out;
out=fopen("out.txt", "w");
for (int i=0; i<block_size; i++)
  fprintf(out, "%c", crypt[i]);
 
  return 0;
}