/// <summary>
/// Extracts the secret image from a ModifiedImage.
/// </summary>
public async Task ExtractSecretImage()
{
var modifiedImageData = await ImageUtilities.GetImageData(this.ModifiedImage);
if (HeaderUtilities.IsMessageEmbedded(modifiedImageData, this.ModifiedImage.PixelWidth) &&
HeaderUtilities.GetMessageType(modifiedImageData, this.ModifiedImage.PixelWidth) ==
MessageType.MonochromeBmp)
{
var imageEncoder = new ImageEncoder();
var secretImageData =
imageEncoder.DecodeImage(modifiedImageData, this.ModifiedImage.PixelWidth,
this.ModifiedImage.PixelHeight);
this.SecretImage = new WriteableBitmap(this.ModifiedImage.PixelWidth, this.ModifiedImage.PixelHeight);
if (!HeaderUtilities.IsEncrypted(modifiedImageData, this.ModifiedImage.PixelWidth))
{
using var writeStream = this.SecretImage.PixelBuffer.AsStream();
await writeStream.WriteAsync(secretImageData, 0, secretImageData.Length);
this.EncryptedSecretImage = null;
}
else
{
this.EncryptedSecretImage =
new WriteableBitmap(this.ModifiedImage.PixelWidth, this.ModifiedImage.PixelHeight);
using var encryptedWriteStream = this.EncryptedSecretImage.PixelBuffer.AsStream();
await encryptedWriteStream.WriteAsync(secretImageData, 0, secretImageData.Length);
using var writeStream = this.SecretImage.PixelBuffer.AsStream();
await writeStream.WriteAsync(ImageUtilities.SwitchImageHalves(secretImageData), 0,
secretImageData.Length);
}
}
else
{
throw new ArgumentException("Modified Image doesn't contain Secret Image");
}
}
/// <summary>
/// Determines whether [is modified image encrypted].
/// </summary>
/// <returns>True if the modified image is encrypted</returns>
public async Task <bool> IsModifiedImageSecretEncrypted()
{
return(HeaderUtilities.IsEncrypted(await ImageUtilities.GetImageData(this.ModifiedImage),
this.ModifiedImage.PixelWidth));
}