/// <summary>
/// Extracts the content from the image
/// </summary>
/// <param name="img">the image from which to extract</param>
/// <param name="planes">the planes to embed in</param>
/// <param name="bitDepth">the bit depth of the embedding</param>
/// <returns>the embedded content, null if a problem occurs</returns>
public static EmbeddingContent Extract(Bitmap img, EmbeddingPlane planes, int bitDepth)
{
// short circuit
if ((img == null) || (bitDepth < 1) || (bitDepth > 8))
{
return(null);
}
// var declatation
EmbeddingContent retVal = null;
try
{
// get the header to determine what to extract
EmbeddingHeader eh = new EmbeddingHeader(img, planes, bitDepth);
// read the bytes
int totalBytesToExtract = eh.ToString().Length + eh.SizeOfContent;
retVal = new EmbeddingContent(SteganographyMethods.ExtractBytes(img, planes, bitDepth, totalBytesToExtract));
}
catch
{
retVal = null;
}
return(retVal);
}
/// <summary>
/// Embeds content in the image
/// </summary>
/// <param name="imageFile">the image file in which to embed</param>
/// <param name="planes">the planes to embed in</param>
/// <param name="bitDepth">the bit depth of the embedding</param>
/// <param name="content">the content to embed</param>
/// <returns>the image with the data embedded if successful, otherwise null</returns>
public static Bitmap Embed(String imageFile, EmbeddingPlane planes, int bitDepth, EmbeddingContent content)
{
// var init
Bitmap retVal = null;
// wrap call
try
{
retVal = new Bitmap(imageFile);
if (SteganographyMethods.Embed(retVal, planes, bitDepth, content) == false)
{
throw new SteganographyException(String.Empty);
}
}
catch
{
if (retVal != null)
{
retVal.Dispose();
}
retVal = null;
}
return(retVal);
}
/// Extracts the content from the image
/// </summary>
/// <param name="imageFile">the image file from which to extract</param>
/// <param name="planes">the planes to embed in</param>
/// <param name="bitDepth">the bit depth of the embedding</param>
/// <returns>the embedded content, null if a problem occurs</returns>
public static EmbeddingContent Extract(String imageFile, EmbeddingPlane planes, int bitDepth)
{
// var init
EmbeddingContent retVal = null;
// wrap call
try
{
using (Bitmap img = new Bitmap(imageFile))
{
retVal = SteganographyMethods.Extract(img, planes, bitDepth);
}
}
catch
{
retVal = null;
}
return(retVal);;
}
/// <summary>
/// Internal constructor that builds the object from bytes
/// </summary>
/// <param name="img">the image in which to embed</param>
/// <param name="planes">the planes to embed in</param>
/// <param name="bitDepth">the bit depth of the embedding</param>
/// <returns>the embedding header</returns>
internal EmbeddingHeader(Bitmap img, EmbeddingPlane planes, int bitDepth)
{
try
{
// get header
byte[] headerBytes = SteganographyMethods.ExtractBytes(img, planes, bitDepth, MAX_HEADER);
String header = System.Text.Encoding.ASCII.GetString(headerBytes).Trim();
String[] split = header.Split(new char[1] {
HEADER_SPLIT_CHAR
});
// set attributes
this.TypeOfContent = (ContentType)Enum.Parse(typeof(ContentType), split[0].Trim());
this.SizeOfContent = Convert.ToInt32(split[1].Trim());
this.Filename = split[2].Trim();
}
catch (Exception e)
{
throw new SteganographyException(e.ToString());
}
}
/// <summary>
/// Get bytes hidden in a picture's plane
/// </summary>
/// <param name="img">the picture to extract data from</param>
/// <param name="planes">what pleanes to extract from</param>
/// <param name="bitDepth">the bit depth to extract [1, 8]</param>
/// <param name="bytesToGet">the number of bytes to retrieve</param>
/// <returns>a byte array of data, null if there is a problem</returns>
internal static byte[] ExtractBytes(Bitmap img, EmbeddingPlane planes, int bitDepth, int bytesToGet)
{
// var declatation
byte[] retVal = new Byte[bytesToGet];
int currentByteIndex = 0;
byte currentBitIndex = 1;
try
{
// loop through the x and y pixels of the image, as well as the correct bit depths
for (int x = 0; x < img.Width; x++)
{
for (int y = 0; y < img.Height; y++)
{
for (byte extractBit = 1; extractBit <= bitDepth; extractBit++)
{
// extract from R
if ((planes == EmbeddingPlane.R) || (planes == EmbeddingPlane.RGB))
{
Color rgb = img.GetPixel(x, y);
byte r = SteganographyMethods.GetBitValueFromByte(rgb.R, extractBit);
retVal[currentByteIndex] = SteganographyMethods.SetBitValueInByte(retVal[currentByteIndex], currentBitIndex, r);
// enumerate bit/byte counter
currentBitIndex++;
if (currentBitIndex > 8)
{
currentBitIndex = 1;
currentByteIndex++;
}
if (currentByteIndex >= bytesToGet)
{
x = img.Width;
y = img.Height;
break;
}
}
// extract from G
if ((planes == EmbeddingPlane.G) || (planes == EmbeddingPlane.RGB))
{
Color rgb = img.GetPixel(x, y);
byte g = SteganographyMethods.GetBitValueFromByte(rgb.G, extractBit);
retVal[currentByteIndex] = SteganographyMethods.SetBitValueInByte(retVal[currentByteIndex], currentBitIndex, g);
// enumerate bit/byte counter
currentBitIndex++;
if (currentBitIndex > 8)
{
currentBitIndex = 1;
currentByteIndex++;
}
if (currentByteIndex >= bytesToGet)
{
x = img.Width;
y = img.Height;
break;
}
}
// extract from B
if ((planes == EmbeddingPlane.B) || (planes == EmbeddingPlane.RGB))
{
Color rgb = img.GetPixel(x, y);
byte b = SteganographyMethods.GetBitValueFromByte(rgb.B, extractBit);
retVal[currentByteIndex] = SteganographyMethods.SetBitValueInByte(retVal[currentByteIndex], currentBitIndex, b);
// enumerate bit/byte counter
currentBitIndex++;
if (currentBitIndex > 8)
{
currentBitIndex = 1;
currentByteIndex++;
}
if (currentByteIndex >= bytesToGet)
{
x = img.Width;
y = img.Height;
break;
}
}
}
}
}
}
catch (Exception)
{
retVal = null;
}
return(retVal);
}
/// <summary>
/// Embeds content in the image
/// </summary>
/// <param name="img">the image in which to embed</param>
/// <param name="planes">the planes to embed in</param>
/// <param name="bitDepth">the bit depth of the embedding</param>
/// <param name="content">the content to embed</param>
/// <returns>true if successful</returns>
public static Boolean Embed(Bitmap img, EmbeddingPlane planes, int bitDepth, EmbeddingContent content)
{
// short circuit
if ((img == null) || (bitDepth < 1) || (bitDepth > 8) || (content == null) || (content.HeaderAndContent.Length > SteganographyMethods.MaxBytesInImage(img, planes, bitDepth)))
{
return(false);
}
// var init
Boolean retVal = true;
int currentByteIndex = 0;
byte currentBitIndex = 1;
try
{
// loop through the x and y pixels of the image, as well as the correct bit depths
for (int x = 0; x < img.Width; x++)
{
for (int y = 0; y < img.Height; y++)
{
for (byte embedBit = 1; embedBit <= bitDepth; embedBit++)
{
// embed in R
if ((planes == EmbeddingPlane.R) || (planes == EmbeddingPlane.RGB))
{
Color rgb = img.GetPixel(x, y);
byte r = SteganographyMethods.SetBitValueInByte(rgb.R, embedBit, SteganographyMethods.GetBitValueFromByte(content.HeaderAndContent[currentByteIndex], currentBitIndex));
img.SetPixel(x, y, Color.FromArgb(r, rgb.G, rgb.B));
// enumerate bit/byte counter
currentBitIndex++;
if (currentBitIndex > 8)
{
currentBitIndex = 1;
currentByteIndex++;
}
if (currentByteIndex >= content.HeaderAndContent.Length)
{
x = img.Width;
y = img.Height;
break;
}
}
// embed in G
if ((planes == EmbeddingPlane.G) || (planes == EmbeddingPlane.RGB))
{
Color rgb = img.GetPixel(x, y);
byte g = SteganographyMethods.SetBitValueInByte(rgb.G, embedBit, SteganographyMethods.GetBitValueFromByte(content.HeaderAndContent[currentByteIndex], currentBitIndex));
img.SetPixel(x, y, Color.FromArgb(rgb.R, g, rgb.B));
// enumerate bit/byte counter
currentBitIndex++;
if (currentBitIndex > 8)
{
currentBitIndex = 1;
currentByteIndex++;
}
if (currentByteIndex >= content.HeaderAndContent.Length)
{
x = img.Width;
y = img.Height;
break;
}
}
// embed in B
if ((planes == EmbeddingPlane.B) || (planes == EmbeddingPlane.RGB))
{
Color rgb = img.GetPixel(x, y);
byte b = SteganographyMethods.SetBitValueInByte(rgb.B, embedBit, SteganographyMethods.GetBitValueFromByte(content.HeaderAndContent[currentByteIndex], currentBitIndex));
img.SetPixel(x, y, Color.FromArgb(rgb.R, rgb.G, b));
// enumerate bit/byte counter
currentBitIndex++;
if (currentBitIndex > 8)
{
currentBitIndex = 1;
currentByteIndex++;
}
if (currentByteIndex >= content.HeaderAndContent.Length)
{
x = img.Width;
y = img.Height;
break;
}
}
}
}
}
}
catch
{
retVal = false;
}
return(retVal);
}
