/// <summary>
/// Initializes encryption keys based on given <paramref name="password"/>.
/// </summary>
/// <param name="password">The password.</param>
protected void InitializePassword(string password)
{
PkblubbClassicManaged pkManaged = new PkblubbClassicManaged();
byte[] key = PkblubbClassic.GenerateKeys(BlubbZipConstants.ConvertToArray(password));
cryptoTransform_ = pkManaged.CreateEncryptor(key, null);
}
/// <summary>
/// Perform the initial read on an entry which may include
/// reading encryption headers and setting up inflation.
/// </summary>
/// <param name="destination">The destination to fill with data read.</param>
/// <param name="offset">The offset to start reading at.</param>
/// <param name="count">The maximum number of bytes to read.</param>
/// <returns>The actual number of bytes read.</returns>
int InitialRead(byte[] destination, int offset, int count)
{
if (!CanDecompressEntry)
{
throw new BlubbZipException("Library cannot extract this entry. Version required is (" + entry.Version.ToString() + ")");
}
// Handle encryption if required.
if (entry.IsCrypted)
{
if (password == null)
{
throw new BlubbZipException("No password set.");
}
// Generate and set crypto transform...
PkblubbClassicManaged managed = new PkblubbClassicManaged();
byte[] key = PkblubbClassic.GenerateKeys(BlubbZipConstants.ConvertToArray(password));
inputBuffer.CryptoTransform = managed.CreateDecryptor(key, null);
byte[] cryptbuffer = new byte[BlubbZipConstants.CryptoHeaderSize];
inputBuffer.ReadClearTextBuffer(cryptbuffer, 0, BlubbZipConstants.CryptoHeaderSize);
if (cryptbuffer[BlubbZipConstants.CryptoHeaderSize - 1] != entry.CryptoCheckValue)
{
throw new BlubbZipException("Invalid password");
}
if (csize >= BlubbZipConstants.CryptoHeaderSize)
{
csize -= BlubbZipConstants.CryptoHeaderSize;
}
else if ((entry.Flags & (int)GeneralBitFlags.Descriptor) == 0)
{
throw new BlubbZipException(string.Format("Entry compressed size {0} too small for encryption", csize));
}
}
else
{
inputBuffer.CryptoTransform = null;
}
if ((csize > 0) || ((flags & (int)GeneralBitFlags.Descriptor) != 0))
{
if ((method == (int)CompressionMethod.Deflated) && (inputBuffer.Available > 0))
{
inputBuffer.SetInflaterInput(inf);
}
internalReader = new ReadDataHandler(BodyRead);
return(BodyRead(destination, offset, count));
}
else
{
internalReader = new ReadDataHandler(ReadingNotAvailable);
return(0);
}
}