Esempio n. 1
0
  /**
   * Method to embed the message into the cover data
   *
   * @param msg Message to be embedded
   * @param msgFileName Name of the message file. If this value is provided, then the filename
   *     should be embedded in the cover data
   * @param cover Cover data into which message needs to be embedded
   * @param coverFileName Name of the cover file
   * @param stegoFileName Name of the output stego file
   * @return Stego data containing the message
   * @throws OpenStegoException
   */
  public byte[] embedData(
      byte[] msg, String msgFileName, byte[] cover, String coverFileName, String stegoFileName)
      throws OpenStegoException {
    BufferedImage image = null;
    List<int[][]> yuv = null;
    DWT dwt = null;
    ImageTree dwtTree = null;
    ImageTree p = null;
    Signature sig = null;
    Pixel pixel1 = null;
    Pixel pixel2 = null;
    Pixel pixel3 = null;
    int[][] luminance = null;
    int imgType = 0;
    int origWidth = 0;
    int origHeight = 0;
    int cols = 0;
    int rows = 0;
    int n = 0;
    double temp = 0.0;

    // Cover file is mandatory
    if (cover == null) {
      throw new OpenStegoException(null, NAMESPACE, DWTXieErrors.ERR_NO_COVER_FILE);
    } else {
      image = ImageUtil.byteArrayToImage(cover, coverFileName);
    }

    imgType = image.getType();
    origWidth = image.getWidth();
    origHeight = image.getHeight();
    image = ImageUtil.makeImageSquare(image);

    cols = image.getWidth();
    rows = image.getHeight();
    yuv = ImageUtil.getYuvFromImage(image);
    luminance = yuv.get(0);
    sig = new Signature(msg);

    // Wavelet transform
    dwt = new DWT(cols, rows, sig.filterID, sig.embeddingLevel, sig.waveletFilterMethod);
    dwtTree = dwt.forwardDWT(luminance);

    p = dwtTree;
    // Consider each resolution level
    while (p.getLevel() < sig.embeddingLevel) {
      // Descend one level
      p = p.getCoarse();
    }

    // Repeat binary watermark by sliding a 3-pixel window of approximation image
    for (int row = 0; row < p.getImage().getHeight(); row++) {
      for (int col = 0; col < p.getImage().getWidth() - 3; col += 3) {
        // Get all three approximation pixels in window
        pixel1 = new Pixel(0, DWTUtil.getPixel(p.getImage(), col + 0, row));
        pixel2 = new Pixel(1, DWTUtil.getPixel(p.getImage(), col + 1, row));
        pixel3 = new Pixel(2, DWTUtil.getPixel(p.getImage(), col + 2, row));

        // Bring selected pixels in ascending order
        if (pixel1.value > pixel2.value) {
          swapPix(pixel1, pixel2);
        }
        if (pixel2.value > pixel3.value) {
          swapPix(pixel2, pixel3);
        }
        if (pixel1.value > pixel2.value) {
          swapPix(pixel1, pixel2);
        }

        // Apply watermarking transformation (modify median pixel)
        temp =
            wmTransform(
                sig.embeddingStrength,
                pixel1.value,
                pixel2.value,
                pixel3.value,
                getWatermarkBit(sig.watermark, n % (sig.watermarkLength * 8)));

        // Write modified pixel
        DWTUtil.setPixel(p.getImage(), col + pixel2.pos, row, temp);

        n++;
      }
    }

    dwt.inverseDWT(dwtTree, luminance);
    yuv.set(0, luminance);
    image = ImageUtil.cropImage(ImageUtil.getImageFromYuv(yuv, imgType), origWidth, origHeight);

    return ImageUtil.imageToByteArray(image, stegoFileName, this);
  }
Esempio n. 2
0
  /**
   * Method to extract the message from the stego data
   *
   * @param stegoData Stego data containing the message
   * @param stegoFileName Name of the stego file
   * @param origSigData Optional signature data file for watermark
   * @return Extracted message
   * @throws OpenStegoException
   */
  public byte[] extractData(byte[] stegoData, String stegoFileName, byte[] origSigData)
      throws OpenStegoException {
    List<Integer> sigBitList = new ArrayList<Integer>();
    BufferedImage image = null;
    DWT dwt = null;
    ImageTree dwtTree = null;
    ImageTree p = null;
    Signature sig = null;
    Pixel pixel1 = null;
    Pixel pixel2 = null;
    Pixel pixel3 = null;
    int[][] luminance = null;
    int cols = 0;
    int rows = 0;
    int n = 0;

    image = ImageUtil.makeImageSquare(ImageUtil.byteArrayToImage(stegoData, stegoFileName));

    cols = image.getWidth();
    rows = image.getHeight();
    luminance = ImageUtil.getYuvFromImage(image).get(0);
    sig = new Signature(origSigData);

    // Wavelet transform
    dwt = new DWT(cols, rows, sig.filterID, sig.embeddingLevel, sig.waveletFilterMethod);
    dwtTree = dwt.forwardDWT(luminance);

    p = dwtTree;
    // Consider each resolution level
    while (p.getLevel() < sig.embeddingLevel) {
      // Descend one level
      p = p.getCoarse();
    }

    // Repeat binary watermark by sliding a 3-pixel window of approximation image
    for (int row = 0; row < p.getImage().getHeight(); row++) {
      for (int col = 0; col < p.getImage().getWidth() - 3; col += 3) {
        // Get all three approximation pixels in window
        pixel1 = new Pixel(0, DWTUtil.getPixel(p.getImage(), col + 0, row));
        pixel2 = new Pixel(1, DWTUtil.getPixel(p.getImage(), col + 1, row));
        pixel3 = new Pixel(2, DWTUtil.getPixel(p.getImage(), col + 2, row));

        // Bring selected pixels in ascending order
        if (pixel1.value > pixel2.value) {
          swapPix(pixel1, pixel2);
        }
        if (pixel2.value > pixel3.value) {
          swapPix(pixel2, pixel3);
        }
        if (pixel1.value > pixel2.value) {
          swapPix(pixel1, pixel2);
        }

        // Apply inverse watermarking transformation to get the bit value
        sigBitList.add(
            invWmTransform(sig.embeddingStrength, pixel1.value, pixel2.value, pixel3.value));
        n++;
      }
    }
    sig.setWatermark(convertBitListToByteArray(sigBitList));

    return sig.getSigData();
  }