Is it possible to view digitally signed pdfs on the iphone or ipad?

When I try to view a sample digitally signed pdf in a UIWebView, I get blank pages. The number of pages is correct, 开发者_如何学运维but they are all blank.

Normal pdfs show up correctly.

I am not looking for signing a pdf, just viewing a signed pdf.

Standard digital signatures in PDF have no influence over page content, they do not encrypt the page content or change it in some way. It is possible that the files have other problems that prevent them from being displayed. Or they are signed and encrypted with a custom security handler and the viewer cannot decrypt them.