Bug: Signature broken
I have a pdf. I sign it. Signature is fine. If I add another signature or the ltv-infos with adobe acrobat, the first signature is broken. (the new content is added incrementaly, obviously there are no changes of the content the first signature hashed.
Original.pdf is the original pdf-file.
Signed1.pdf here I added a signature (not with adobe)
signed1ltv.pdf here I added the "prüfinformationen" with adobe acrobat -> broken
signed1and2withoutltv.pdf here the first signature invalids with the second signature (done by adobe acrobat)
All other test-programms (like dss validation service from the eu) say "all signatures are fine". So, what causes the adobe acrobat (newest version) to say "signature is broken" ???
Thanks
Bernd
Bernd Hohmann
shared this idea
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mkl
commented
There is a small error in your original PDF. A similar error is explained in this Adobe community forum post: https://community.adobe.com/t5/acrobat-discussions/digital-signature-shows-valid-in-bluebeam-and-docusign-prepare-amp-sign-but-not-adobe/m-p/12409150#M331106
As we know, PDF viewers in general ignore or repair a lot of minor errors, so no viewer warns about it. Adobe Acrobat also ignores it. Usually that is. Except when checking for a signature (except the final signature of the document) whether there are any disallowed later changes, in that case that error results in such a validation failure.