Method keySched

Libraries/unrar/rijndael.cpp:332–401

void Rijndael::keySched(byte key[_MAX_KEY_COLUMNS][4])
{
  int j,rconpointer = 0;

  // Calculate the necessary round keys
  // The number of calculations depends on keyBits and blockBits
  int uKeyColumns = m_uRounds - 6;

  byte tempKey[_MAX_KEY_COLUMNS][4];

  // Copy the input key to the temporary key matrix

  memcpy(tempKey,key,sizeof(tempKey));

  int r = 0;
  int t = 0;

  // copy values into round key array
  for(j = 0;(j < uKeyColumns) && (r <= m_uRounds); )
  {
    for(;(j < uKeyColumns) && (t < 4); j++, t++)
      for (int k=0;k<4;k++)
        m_expandedKey[r][t][k]=tempKey[j][k];

    if(t == 4)
    {
      r++;
      t = 0;
    }
  }
    
  while(r <= m_uRounds)
  {
    tempKey[0][0] ^= S[tempKey[uKeyColumns-1][1]];
    tempKey[0][1] ^= S[tempKey[uKeyColumns-1][2]];
    tempKey[0][2] ^= S[tempKey[uKeyColumns-1][3]];
    tempKey[0][3] ^= S[tempKey[uKeyColumns-1][0]];
    tempKey[0][0] ^= rcon[rconpointer++];

    if (uKeyColumns != 8)
      for(j = 1; j < uKeyColumns; j++)
        for (int k=0;k<4;k++)
          tempKey[j][k] ^= tempKey[j-1][k];
    else
    {
      for(j = 1; j < uKeyColumns/2; j++)
        for (int k=0;k<4;k++)
          tempKey[j][k] ^= tempKey[j-1][k];

      tempKey[uKeyColumns/2][0] ^= S[tempKey[uKeyColumns/2 - 1][0]];
      tempKey[uKeyColumns/2][1] ^= S[tempKey[uKeyColumns/2 - 1][1]];
      tempKey[uKeyColumns/2][2] ^= S[tempKey[uKeyColumns/2 - 1][2]];
      tempKey[uKeyColumns/2][3] ^= S[tempKey[uKeyColumns/2 - 1][3]];
      for(j = uKeyColumns/2 + 1; j < uKeyColumns; j++)
        for (int k=0;k<4;k++)
          tempKey[j][k] ^= tempKey[j-1][k];
    }
    for(j = 0; (j < uKeyColumns) && (r <= m_uRounds); )