Is it possible to configure the FlexPaper reader to un-encrypt password-protected pdfs or swfs?

Here is the use-case:

1. User uploads a pdf
2. My server would then convert the pdf to swf via pdf2swf
3. Then somehow encrypt the swf with a password (not sure best way to do this)
4. Then the FlexPaper would be able to un-encrypt the swf and display it

What I am trying to avoid is the caching of readable swf in the browser's cache.

Any ideas on the best way to achieve this?

I know, even with this it will not be a fully secure solution, but certainly helps.

Note: I am running this on Linux and OS X and using Rails.

Thanks!

Jonathan