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Posted to dev@pdfbox.apache.org by Tilman Hausherr <TH...@t-online.de> on 2023/11/03 16:24:30 UTC
Converting obfuscate PDFs to PS and back to PDF
https://www.danisch.de/blog/2023/10/31/aktennotiz-zu-pdftotext-bei-vermurksten-zeichensaetzen/
The text is in german but what he says that he was able to extract text
from obfuscated PDFs by converting them to PostScript and then back to
PDF. I didn't test this myself but I suspect that the conversion to
PostScript dumps the /ToUnicode stream, and that it is rebuilt from the
font itself when the conversion is done.
Tilman
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Re: Converting obfuscate PDFs to PS and back to PDF
Posted by Tilman Hausherr <TH...@t-online.de>.
On 08.11.2023 07:23, Andreas Lehmkühler wrote:
>
>
> Am 03.11.23 um 17:24 schrieb Tilman Hausherr:
>> https://www.danisch.de/blog/2023/10/31/aktennotiz-zu-pdftotext-bei-vermurksten-zeichensaetzen/
>>
>>
>> The text is in german but what he says that he was able to extract
>> text from obfuscated PDFs by converting them to PostScript and then
>> back to PDF. I didn't test this myself but I suspect that the
>> conversion to PostScript dumps the /ToUnicode stream, and that it is
>> rebuilt from the font itself when the conversion is done.
> The information has to be somehwere otherwise such "conversion" won't
> work.
>
> @Tilman did you try to contact the author to ask for an example?
No because I didn't expect to get a PDF, he mentioned account
statements. It's just a thing to keep in mind the next time we hit such
a file.
Tilman
>
> Andreas
>>
>> Tilman
>>
>>
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>
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Re: Converting obfuscate PDFs to PS and back to PDF
Posted by Andreas Lehmkühler <an...@lehmi.de.INVALID>.
Am 03.11.23 um 17:24 schrieb Tilman Hausherr:
> https://www.danisch.de/blog/2023/10/31/aktennotiz-zu-pdftotext-bei-vermurksten-zeichensaetzen/
>
> The text is in german but what he says that he was able to extract text
> from obfuscated PDFs by converting them to PostScript and then back to
> PDF. I didn't test this myself but I suspect that the conversion to
> PostScript dumps the /ToUnicode stream, and that it is rebuilt from the
> font itself when the conversion is done.
The information has to be somehwere otherwise such "conversion" won't work.
@Tilman did you try to contact the author to ask for an example?
Andreas
>
> Tilman
>
>
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> To unsubscribe, e-mail: dev-unsubscribe@pdfbox.apache.org
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