title: Can iTextSharp 5.5.9 open a PDF which has been 256-bit encrypted?
body: <p>I am getting error "Unknown encryption type R=6" when attempting to instantiate a PDFReader:</p>
  
  <pre><code>var reader = new PdfReader(bytearray, new AsciiEncoding().GetBytes(ownerPassword));
  </code></pre>
  
  <p>I can see that iTextSharp can encrypt at 256-bits but can it decrypt?</p>
  
  <p>P.S. The PDF was encrypted using Acrobat Pro XI.</p>