Bug 146211 - export to PDF/A-2b removes (qualified) signature
Summary: export to PDF/A-2b removes (qualified) signature
Status: RESOLVED INSUFFICIENTDATA
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Draw (show other bugs)
Version:
(earliest affected)
7.2.4.1 release
Hardware: All All
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-12-13 15:18 UTC by Ralf Hauser
Modified: 2024-01-11 10:16 UTC (History)
1 user (show)

See Also:
Crash report or crash signature:


Attachments
DOC_conv24-sig.pdf (71.01 KB, application/pdf)
2021-12-13 15:18 UTC, Ralf Hauser
Details

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Description Ralf Hauser 2021-12-13 15:18:14 UTC
Created attachment 176908 [details]
DOC_conv24-sig.pdf

The signed document is unfortunately not pdf-A-compliant.
After the export it is, but it is not ok, to silently remove the signature
Comment 1 Sanchu Manthiram Shanmugam 2022-12-03 07:21:11 UTC
Please clarify: PDF signing only works with x509 certificates


kindly confirm if x509 certificates were used.

more info: https://bugs.documentfoundation.org/show_bug.cgi?id=115884



Hello,

Thank you for reporting the bug. Can you please confirm if the issue still exists in the latest build?


Could you please try to reproduce it with a master build from https://dev-builds.libreoffice.org/daily/master/ ?
You can install it alongside the standard version.

I have set the bug's status to 'NEEDINFO'. Please change it back to 'UNCONFIRMED' if the bug is still present in the master build.
Comment 2 QA Administrators 2023-06-03 03:16:30 UTC Comment hidden (obsolete)
Comment 3 Alex Thurgood 2023-06-13 15:34:07 UTC
I can confirm something similar, on macOS when exporting to PDF/A-3a.

I have an EIDAS hardware certificate (USB key) issued by CertEurope that uses Trusted Key Manager for making the key available to the OS.

I have set up a security device per the supplier's recommendations in Firefox so that the key is readable in a Firefox profile session after entry of a PIN associated with the certificate on the physical USB key.

I can use this key to digitally & validly sign PDF files separately in Adobe Reader.

I can also use the key within Firefox (via the security device configuration tool under Security & Certificates)  to login to a court CMS for which the certificate and key are required for the filing of signed and authenticated transactions with the court CMS.


However, in LibreOffice, after the usual idiocy (bug 147291 or bug 153626) of not being able to find a Certificate Manager, I can finally get LO to display an entry dialog for the PIN, when I click directly on the "Sign" button (which otherwise shows no available certificates).

I can then sign an ODT, but LibreOffice reports that it could not verify the signature.

One has to ask how it can activate the digital signature and not be able to validate it ?
What use is a X509 signature that isn't validated by the software application that adds it to the document ?

CertEurope uses SHA-256 with RSA Encryption.

If I export the signed ODT to PDF(A/3b), opening the PDF in Adobe Reader doesn't show the document as being signed, it seems that the signature is silently removed, or not compliant with the PDF-A spec.

If I create an ODT without a signature, export to PDF using the signature tab (which finds my X509 cert), the signature is considered valid in the PDF when opened in Adobe Reader.

Am I missing something, or does signing X590 within the ODT not do anything actually useful, and is it scrubbed when exporting the signed ODT to PDF/A2/3 ?
Comment 4 QA Administrators 2023-12-11 03:14:46 UTC Comment hidden (obsolete)
Comment 5 QA Administrators 2024-01-11 03:13:12 UTC Comment hidden (obsolete)
Comment 6 Alex Thurgood 2024-01-11 10:16:17 UTC
At a minimum, this report could have been converted to a RFE, such as "Support Electronic Signature Types Other Than X.509 in PDF Export".