Partial document security changed in 2.5.1?

I frequently create PDF documents that can be opened freely, but require a password before they can be edited or have text extracted. I use three profiles ( Open, Open but Secure, and Secured) to allow this.
I also use NitroPro as a reader and editor.

Prior to installing 2.5.1 I could open documents created with both of the “Open…” profiles without needing a password. Now Nitro will not open the Open but secure profile at all - even with a password. before it would open freely but warn that the file was secured. It opens secured documents using the password without any trouble.

Something has changed in the security model in the last release of PDFCreator. Does anyone have any idea what so that I can prod Nitro.

Hey @wisty,

I can’t recreate that issue with my PDF Readers. Did NitroPro get an update that might cause the issue?

Please provide the settings of your “Open but Secure” profile, so I can further investigate that.

Best regards!

Thanks Florian. Nothing has changed in Nitro. I have just installed PDF Creator 2.4.1 in a VM as an experiment. If I create the same document using 2.4.1, it opens fine in NitroPro (both 9 & 11). I have no problems with other readers - all the ones I have tried work as expected. But something has changed in the security model between 2.41 and 2.5.1 and it has broken Nitro. If I can find out what I can let them know.

The Open but secure profile is the default profile except that in the PDF security tab “Encrypt PDF…” is ticked, “Require password to open…” is unticked. Medium encryption . Allow user to print and to use screen reader are both ticked - the rest are unticked.

Is there a way to upload files to the forum? If there is I could upload two samples, one 2.4.1 and one 2.5.1 for investigation.

I think I have spotted the difference. Despite the two profiles being identical in terms of the options selected, 2.4.1 uses PDF version 1.4 while 2.5.1 uses version 1.6.

The difference seems to be that in 2.4.1 the medium encryption is 128 bit, while in 2.5.1 it is shown as 128 bit AES. Presumably this change pushes the version up.

Nitro can clearly handle 128bit AES as it can open fully secured documents that use it. and as other readers can cope with documents created with the profile it seems that it is unlikely to be PDFCreator.

It would be nice if you could check however.


if you are using a business edition, the library used internally for applying the security changed from iText to pdftools. You can still use 128 bit encryption without AES if you select the lowest level in the current version.

Best regards,