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From Tilman Hausherr <THaush...@t-online.de>
Subject Re: Signed PDF with non-encrypted headers causes issue in PDFBox 2.0.9
Date Tue, 24 Apr 2018 19:36:27 GMT
I had a quick look... yes the document info is unencrypted which is 
incorrect. EncryptMeta is false but this applies only to XMP metadata 
streams.

Tilman

Am 24.04.2018 um 12:48 schrieb Evert-Jan de Bruin:
>
> Hello,
>
> For my project I have to merge PDF files together. This usually works 
> fine, but it does not always work with digitally signed PDF files.
>
> Simply a load() of the document will already fail with 
> InvalidBlockSizeException. Here is an example document: 
> https://ufile.io/mgshz
>
> I went into the PDFBox code, and the issue seems to be that it detects 
> AES encryption in the PDF due to the digital signature, but then 
> assumes everything is encrypted and needs to be decrypted. However, 
> the headers are **not** encrypted so decryption fails.
>
> I can get it all to work by going to PDFParser.java and disabling 
> these three lines in prepareDecryption():
>
> //                securityHandler = encryption.getSecurityHandler();
>
> // securityHandler.prepareForDecryption(encryption, 
> document.getDocumentID(),
>
> // decryptionMaterial);
>
> // accessPermission = securityHandler.getCurrentAccessPermission();
>
> However, this is of course very ugly as decryption is now totally 
> disabled. I also get warnings about offset issues but the end result 
> seems fine.
>
> Is there a more elegant solution or is this really a bug?
>
> It seems to be a repetition of 
> https://issues.apache.org/jira/browse/PDFBOX-3229 
> <https://issues.apache.org/jira/browse/PDFBOX-3229> but this should 
> have been fixed in 2.0.0, however, it still occurs in 2.0.9
>
> Regards,
>
> Evert-Jan de Bruin
>
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