code: private void computeIv(byte label) {
          for (int i = 0; i < 14; i++) {
              ivStore[i] = masterSalt[i];
          }
          ivStore[7] ^= label;
          ivStore[14] = ivStore[15] = 0;
      }
docs: Compute the initialization vector, used later by encryption algorithms,
  based on the label.
  
  @param label label specified for each type of iv