How to disable "AllowPrinting" for PDF generated in cfreport/cfdocument?

The business requirement says that the PDF cannot be printed.

I looked up the doc of cfreport, and it says for format="pdf", there is a permissions attribute that I can set to a list of permissions including AllowPrinting.

However, setting permissions="" does not take away the printing permission. I checked by Right Cick on Adobe Reader browser plugin -> Document Property -> Sec开发者_Python百科urity, it says Printing: Allowed"

How do I disable printing? Thanks.

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Found out in the doc of CFPDF that encryption attribute must be set before it respects permissions attribute!