/// <summary>
/// Decrypts the specified region of the input byte array and copies the decrypted data to the specified region of the output byte array.
/// </summary>
/// <param name="inputBuffer">The input data to decrypt.</param>
/// <param name="inputOffset">The offset into the input byte array from which to begin using data.</param>
/// <param name="inputCount">The number of bytes in the input byte array to use as data.</param>
/// <param name="outputBuffer">The output to which to write decrypted data.</param>
/// <param name="outputOffset">The offset into the output byte array from which to begin writing data.</param>
/// <returns>
/// The number of bytes decrypted.
/// </returns>
public override int DecryptBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
{
if ((inputOffset + this.BlockSize) > inputBuffer.Length)
{
throw new IndexOutOfRangeException("input buffer too short");
}
if ((outputOffset + this.BlockSize) > outputBuffer.Length)
{
throw new IndexOutOfRangeException("output buffer too short");
}
if (this._decryptionKey == null)
{
this._decryptionKey = GenerateWorkingKey(false, this.Key);
}
DesCipher.DesFunc(this._decryptionKey, inputBuffer, inputOffset, outputBuffer, outputOffset);
return(this.BlockSize);
}
