White images when rasterizing PDF --> forgot to initialize security handler.

Q:

We are using PDFTron PDF SDK to extract pdf to jpg.

With most pdf it works well but we have a problem with some others
one.
The extracted image is just a white page without anything. Our PDF
files have many pages (abouto 100-200) and all of them are converted
to white pictures ! Did you ever notice this bug ?

PDFNet.Initialize();
PDFNet.SetResourcesPath(HttpContext.Current.Server.MapPath("~/
Resources"));
pdftron.PDF.PDFDoc doc = new pdftron.PDF.PDFDoc(path + ID + ".pdf");
pdftron.PDF.PDFDraw draw = new pdftron.PDF.PDFDraw(72);
pdftron.PDF.Page page = doc.PageFind(1).Current();

draw.SetImageSize(125, 168);
draw.GetBitmap(page).Save(path + "FirstPage.jpg",
  System.Drawing.Imaging.ImageFormat.Jpeg);
----

A:

I found the solution to my problem.
PDFs i tried to open were protected by a password

Calling doc.InitSecurityHnadler() or
doc.InitStdSecurityHnadler("mypass")
after creating the PDFDoc will do the trick.