/// <summary>
/// Exports the text from the selected image file by starting from top left corner.
/// </summary>
public void Export()
{
_form.ExportTextBoxText = string.Empty;
_form.Sw = new Stopwatch();
_form.Sw.Start();
_form.ExportProgressBarValue = 0;
var importedTextLength = CheckBeforeExport();
if (importedTextLength != 0)
{
_form.Bmp = new Bitmap(_form.ExportPictureBoxImage);
int totalBytes = importedTextLength * 7;
int totalPixels = totalBytes / 3;
int totalBytesMod3 = totalBytes % 3;
if (totalBytesMod3 != 0)
{
totalPixels++;
}
_form.ExportProgressBarMaximum = importedTextLength + totalPixels;
var bytesToExport = _helper.GetOnlyNecessaryBytesFromImage(totalPixels, totalBytesMod3, _form.ExpProgressBar);
int pointer = 6; //++++
string bytesToExportLast = string.Empty;
string importedText = null;
for (int l = 0; l < totalBytes; l++) // Getting the last bit of each bytes and stores to 'bytesToExportast'
{
bytesToExportLast += bytesToExport.Substring(pointer, 2);
pointer += 8;
}
int decrease = 0, k = 0, temp = 0;
importedText = string.Empty;
for (int j = 0; j < bytesToExportLast.Length / 14; j++)
{
for (int i = k; i < k + 14; i++)
{
temp += Convert.ToInt32(bytesToExportLast.Substring(i, 1)) * (int)Math.Pow(2, (13 - decrease));
decrease++;
}
if (temp >= 1000)
{
importedText += Encoding.Unicode.GetString(BitConverter.GetBytes(temp + 43032)).TrimEnd((Char)0);
}
else if (temp < 13)
{
importedText += _helper.NumberToTurkishChar(temp);
}
else
{
importedText += Encoding.Unicode.GetString(BitConverter.GetBytes(temp)).TrimEnd((Char)0);
}
_form.ExpProgressBar.Increment(1);
k += 14; temp = decrease = 0;
}
//_form.ExportTextBoxText = importedText;
_form.ExportTextBoxText = EllipticCurvesEncryption.DecryptString(importedText);
SetInfoLabels();
}
else
{
MessageBox.Show("This is not a stego file!", CommonConstants.WarningCaption, MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
/// <summary>
/// Imports the text into the selected image file by starting from top left corner.
/// </summary>
public void Import()
{
//cryptText = EllipticCurve.CryptInfo(_form.ImportTextBoxText);
cryptText = EllipticCurvesEncryption.EncryptString(_form.ImportTextBoxText);
_form.Sw = new Stopwatch();
_form.Sw.Start();
_form.ImportProgressBarValue = 0;
if (CheckBeforeImport())
{
string bitsToImport = string.Empty;
var charsToImport = cryptText.ToCharArray();
var totalBytes = charsToImport.Length * 7;
var totalPixels = totalBytes / 3; // Total number of pixels to be used..
var totalBytesMod3 = totalBytes % 3;
if (totalBytesMod3 != 0)
{
totalPixels++;
}
_form.ImportProgressBarMaximum = totalPixels + totalBytes;
var charToBits = string.Empty;
foreach (var chr in charsToImport)// bitsToImport holds the bit form of the character that will be imported.
{
if (chr >= Korea_First_Index)
{
charToBits = Convert.ToString(chr - Korea_First_Index + 1000, 2);
//(Chr - Korean_First_Index is to reduce 16 bits to 14 bits) (The reason that add 1000 to text is to protect overlapping with turkish).
}
else
{
charToBits = Convert.ToString(chr, 2); //if chr is not Korean, change to binary
}
if (charToBits.Length > 7 && charToBits.Length < 9) // if it's binary is between 7 and 9
{
bitsToImport += _helper.TurkishCharTo7Bit(chr); // set to 14 bits in Turkish letter
}
else
{
bitsToImport += charToBits.PadLeft(14, '0'); // If less than 14 bits, padding the leading 0
}
}
var imageBits = _helper.GetOnlyNecessaryBytesFromImage(totalPixels, totalBytesMod3, _form.ImpProgressBar);
int sevenBitPointer = 0, oneBitPointer = 0;
var imageBitsLast = string.Empty;
while (bitsToImport.Length > oneBitPointer) //bitsToImport is importing into imagebits. the result is stored in imageBitLast.
{
imageBitsLast += imageBits.Substring(sevenBitPointer, 6) + (bitsToImport.Substring(oneBitPointer, 2));
oneBitPointer = oneBitPointer + 2;
sevenBitPointer += 8;
_form.ImpProgressBar.Increment(1);
}
ImportTextLength();
imageBitsLast += imageBits.Substring(sevenBitPointer);
_form.ImportPictureBoxImage = _form.Bmp = _helper.ByteArrayToBitmap(_helper.StringToByteArray(imageBitsLast));
SetInfoLabels();
}
}
