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https://issues.apache.org/jira/browse/TIKA-4082?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17732848#comment-17732848
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Peter Wyatt commented on TIKA-4082:
-----------------------------------
Note sure what Tika can really do about such things… same as if you encountered
any of the many DRM or eBook solutions that are layered on top of PDF.
Assuming PDFBox plays nice 😀, you +can+ still read the full structure of the
PDF and get a lot of info, since encryption only impacts PDF strings and
streams – not dictionaries, names, Booleans, arrays, indirect references,
numbers, keywords, etc. Obviously text content is locked away in content
streams which will be encrypted. This is a trick I use with Arlington when
using pdfium. The issue for embedded files is that the filename inside the PDF
is a string object and that will be encrypted – but you can still know and
report that one or more File Specification dictionaries exist and maybe the
annotation, Associated File, or other PDF feature that they are referenced
from, even without the password. But the filename will be obscured by the
encryption.
> Extraction from Microsoft Sharepoint protected PDFs doesn't expose exception
> like other parsers.
> ------------------------------------------------------------------------------------------------
>
> Key: TIKA-4082
> URL: https://issues.apache.org/jira/browse/TIKA-4082
> Project: Tika
> Issue Type: Bug
> Components: parser
> Affects Versions: 2.4.1
> Reporter: Carey Halton
> Priority: Minor
> Attachments: MSFT Transcript FY23-Q3.pdf,
> PasswordProtectedWorkbook.xlsx, Screenshot from 2023-06-14 18-13-21.png,
> password protected pdf exception.txt, password protected xlsx exception.txt,
> screenshot-1.png
>
>
> I have attached a PDF file (see "MSFT Transcript FY23-Q3.pdf") that we are
> currently attempting to extract content from using Tika 2.4.1 (via Tika
> server), but since the file has had password protection added to it via
> Microsoft Sharepoint service, instead of getting the actual file content, we
> get content that says this:
> "
> _This PDF file is protected_
> __
> _You'll need a different reader in order to view this content:_
> _Download a compatible PDF reader._
> __
> _This PDF Document has been protected._
> _The reader you are using does not support opening files protected by
> Microsoft Office_
> _http://go.microsoft.com/fwlink/?LinkID=231373_
> "
> Which is fine since the original content can obviously not be accessed
> without the password. It also throws an exception that we can see in
> "X-TIKA:EXCEPTION:embedded_warning" that is attached in the file "password
> protected pdf exception.txt".
> But we were surprised that we see any content at all as we have a similar
> document (see attached "PasswordProtectedWorkbook.xlsx") that we test with
> that is password protected in a similar way, albeit a XLSX instead of a PDF,
> that doesn't return any content and throws an exception in
> "X-TIKA:EXCEPTION:container_exception" (attached in "password protected
> xlsx.txt"), which we currently treat as a failure mode. whereas we don't
> currently treat "X-TIKA:EXCEPTION:embedded_warning" as a failure.
> I realize these are different parsers, but since it is a very similar
> scenario, should they not be treated in the same way, at least voiding all
> content and emitting a proper failing exception instead of just what appears
> to be considered a warning? We are hesitant to make all instances of
> "X-TIKA:EXCEPTION:embedded_warning" as failures as we are unsure what other
> kinds of errors can be surfaced in that way. But it is clear to us that
> password protected files should be considered as failed to process. Thoughts?
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