PDF Redaction

[TexFly]

Hello,
Is there any way I can check with your library if a PDF has been redacted?
I just need a y/n verification.
Thanks!

[JorjMcKie]

All you can do is detect whether redaction annotations exists ... while they do exist.
No difference to other annotation types here.

If a redaction is being applied, it will be deleted - without a trace.
Along with its removal, other things may have been removed too: text, images or hyperlinks - or not, depending on what had been covered by the redaction's rectangle.

Assuming common sense saving options have been used, there is nothing left in the PDF that betrays what has happened.

Common sense or reasonable saving options are ones that remove unused and duplicate objects, i.e. garbage=2 at least.

The existence of previous PDF versions is only possible if those versions are kept by intention, i.e. incremental saves.

There also is the PDF's /ID field in the trailer. This contains two hash values, one resembling the original version, the second one may indicate that some change has taken place since creation. But this is a highly unreliable indicator, and may not be used at all.

So the answer to your question is "No", because it is impossible. And that does not depend on a tool.

To convince you: here is an example of a PDF x.pdf from which text "word2" has been redacted away giving y.pdf. Both are ASCII text only. Nothing in y.pdf betrays that a redaction has taken place.
redact.zip

[TexFly]

I tried but unfortunately, I do not get any results (meaning the fitz.PDF_ANNOT_REDACT does not catch anything) . I know the file I'm scanning has a redaction because I put it in there.

What else can I try? Should I try with all the Annotation Types?

Thanks.

[JorjMcKie]

yeah, look at the page and load this annotation to see what it actually is.

[TexFly]

I have looped through all the Annotation Types, and tried multiple files where I actually see a redaction but nothing gets caught. What else can I try?

[JorjMcKie]

Sorry for the delayed reaction.
If you loop through all annotations of a page and do not encounter a redaction, then there is no redaction annotation - no matter what you are seeing on the page.