PDF viewer - issue with protected files

I'm in trouble with PDF viewer Vision component, accessing PDF files protected and encrypted.

The viewer is prompting for a password, however is not opening the file with a message saying that in the ICE viewer configuration (which and how?) is missing the security profile.

The .pdf files are opened with any other pdf viewer, like Acrobat reader.

I tried also to change the encryption to 40 bits and 128 bits too (from 256 bits). In such cases the file is opened, indeed it is corrupted and not readable (again, the files are perfectly readable with other pdf viewer/Acrobat).

We are running in trouble with the client in the Pharma industry, where files must be protected as per above.

Any idea/help?

ADD-ON: I generated the file with "system.report.executeAndDistribute" without ANY further encryption/modification and in the PDF viewer I see as in the attached screenshot. The same file is readable with Acrobat. It seems a problem with fonts/chars