So how do I decrypt a PDF?

[Guest]

I already know the password, but I want to decrypt it so I can view it on mobile devices. The password only works if the file is in the same folder as a certain PFX file. But in any OS other than Windows, this is completely meaningless, and thus I can not view the file even though I know the password. How can I decrypt such a file?

Forgive me if this is the most ignorant question ever.

[Test Screen Name]

Do you have Acrobat Pro?

Whether you have Acrobat Pro or Reader, please open the file and use File > Properties. Under the security tab, what does it say for "Security method"?

[Bernd Alheit]

Did the document use certificate security?

[Guest]

Thanks for the replies guys.

Yeah it uses certificate security.

[Bernd Alheit]

‌Acrobat Reader for mobile devices doesn't support this.

[Test Screen Name]

Bernd, I think that's why the original poster wants to decrypt it, so the unprotected file can be read on a mobile device.

But, I may be wrong, I think you would need the original certificate used to make the file to do that. I think one design aim of certificate security is that you cannot take it off.

[Guest]

So what are my options? I'm out of luck?

If I am unable to decrypt it, are there any other PDF-reading softwares which support decryption on mobile devices?

[Test Screen Name]

‌Out of luck by design I think.

[Guest]

This whole issue is so stupid. I downloaded these PDFs from a website which clearly is trying to disseminate them and has clear instructions for how to open the files. I don't know why they bothered with this encryption business to begin with. Presumably only to make me suffer.

In any case, thanks to everyone for the responses. I appreciate your time.

[Test Screen Name · Accepted solution]

This is a form of Digital Rights Management (DRM). They have clearly done this to stop files from being shared, and if anyone could decrypt the file then the file could be shared. So you can't. DRM is (some googling will show) a HUGELY controversial thing.

[Bernd Alheit]

When printing is allowed you can print and scan the document.

[IsakTen-RwIoo2]

You can also print it to Adobe Printer (comes with the Acrobat Pro) and get flattened PDF this way.

[Bernd Alheit]

‌The printer "Adobe PDF" doesn't allow this for protected documents.