Review

3

sos/mrtd/SecureMessagingWrapper.java

readDO8E(DataInputStream, byte[])

class SecureMessagingWrapper {
   /**
    * The <code>0x8E</code> tag has already been read.
    *
    * @param in inputstream to read from.
    */
   private void readDO8E(DataInputStream in, byte[] rapdu) throws IOException, GeneralSecurityException {
      int length = in.readUnsignedByte();
      if (length != 8) {
         throw new IllegalStateException("DO'8E wrong length");
      }
      byte[] cc1 = new byte[8];
      in.readFully(cc1);
      mac.init(ksMac);
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      DataOutputStream dataOut = new DataOutputStream(out); 
      ssc++;
      dataOut.writeLong(ssc);
      byte[] paddedData = Util.pad(rapdu, 0, rapdu.length - 2 - 8 - 2);
      dataOut.write(paddedData, 0, paddedData.length);
      dataOut.flush();
      byte[] cc2 = mac.doFinal(out.toByteArray());
      if (!Arrays.equals(cc1, cc2)) {
         throw new IllegalStateException("Incorrect MAC!");
      }
   }

}