public void decrypt(byte[] in,int length){
  int pos=0;
  while (pos < in.length && pos < length) {
    decryptBlock(in,pos,length);
    pos+=blockSize;
  }
}

public void decrypt ( byte [ ] in , int length ) { int pos = 0 ; while ( pos < in . length && pos < length ) { decryptBlock ( in , pos , length ) ; pos += blockSize ; } }
perform pseudo " in - place " encryption
