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Signing xlsx with SecureBlackBox.NET v11 corrupts file

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Posted: 09/02/2013 04:06:27
by Andreas Christoforou (Standard support level)
Joined: 09/01/2013
Posts: 12


During our evaluation of SecureBlackbox v10 & v11 (SecureBlackbox for all supported .NET platforms - Version 10.0.233 & SecureBlackbox for all supported .NET platforms - Version 11.0.238) we found that when we sign an Excel xslx file with Version 11.0.238 the resulting file is corrupted.

When trying to open a file, signed with SecureBlackbox.NET v11 SecureOffice sample application, using Excel 2007, Excel 2010 or Excel 2013 we get a "We found a problem with some content in 'Exce_Test.xlsx'. Do you want us to try to recover as much as we can? If you trust the source of this workbook click yes'.

After recovering the file the signature is invalidated with the message 'the signed content has been modified'.

Using SecureBlackbox.NET v10 SecureOffice sample application, to sign Excel files, results in valid xlsx files.

Is this a bug?

Thank you

Posted: 09/02/2013 04:09:09
by Eugene Mayevski (EldoS Corp.)

We did certain code review and in version 11, so it's possible that something got broken. Thank you for reporting the issue, we will investigate it today.

Sincerely yours
Eugene Mayevski
Posted: 09/02/2013 04:30:53
by Eugene Mayevski (EldoS Corp.)

This appeared to be a side-effect of new evaluation restrictions. There's an extra SecureBlackboxEvalInfo.txt file in archive and Office doesn't like it. If you remove that file, the document is opened file.

The time-limited key, which we issue on request, also solves this problem.

Sincerely yours
Eugene Mayevski
Posted: 09/02/2013 09:12:09
by Andreas Christoforou (Standard support level)
Joined: 09/01/2013
Posts: 12

Thank you Eugene for your prompt response.

I tried your suggestion and it works.

So to make things clear, with a time-limited key or a valid paid key signing office files will work as intended.

Best regards
Andreas Christoforou
Posted: 09/02/2013 09:14:01
by Eugene Mayevski (EldoS Corp.)

Yes, absolutely. We will update our code to not put this file in Office components in the evaluation version as well.

Sincerely yours
Eugene Mayevski
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Access locked and protected files in Windows, read and write disks and partitions and more.



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