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error:Digital Signature validation


We experience a problem opening signed Word document.

Exception with message:
"Unable to cast object of type ' ’ to type ' '."
is thrown from:
Document document = new Document(inStream);

Word document is signed with Gost algorithm suite (Russian cryptographic standard).

We are not interested in signature validation by Aspose.Words library.
It would be enough just to open (parse) document without errors.
We use Aspose.Words for document convertion between word to pdf formats.

Previous version of Aspose.Word we used (15.1.0) successfully opens such document.
Current version (15.9.0) fails.

Example of signed document with Gost alg suite is placed in attachment.


NB: Aspose.Word also fails open a document if it is signed with SHA256 hash.

Hi there,

Thanks for your inquiry. I
have tested the scenario and have managed to reproduce the same issue at
my side. For the sake of correction, I have logged this problem in our
issue tracking system as WORDSNET-12579.

I have also tested this scenario using older version v15.1.0. The old version also throws the exception. However, the exception detail is different.

You will be notified via this forum thread once
this issue is resolved. We apologize for your inconvenience.

The issues you have found earlier (filed as WORDSNET-12579) have been fixed in this .NET update and this Java update.

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