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I need to convert encrypted pdf->text with the password given by the user.

IN C++

I am able to open(unencrypted) pdf by using VC++ using zlib.
I am opening pdf in 'rb' mode

Do I need to write a custom function to decrypt stream by the given password ?

[STATUS: code working for unencrypted PDF ]


I have found code in java which do PDF to Text extraction by using PDFBox-0.7.3, but have some issues with the code.
There is a null pointer exception at PDFBox-0.7.3\src\org\pdfbox\

 AccessPermission ap = document.getCurrentAccessPermission();  
if (!ap.canExtractContent())[^]

[STATUS: code just creates empty file ]

Am I doing extraction of the pdf in wrong way ?
What can be the correct steps to decrypt PDF ?
Posted 22-Mar-11 19:19pm
Edited 24-Mar-11 3:36am
Dalek Dave433.2K
Richard MacCutchan at 23-Mar-11 5:05am
So what is your problem? Have you checked the zlib documentation?
01.mandar at 24-Mar-11 8:53am
user inputs are pdf path ,password ,txt file
i need to decrypt pdf by user password
how to decrypt stream ?
will inflate() versions be useful

is above possible to do in zilb?
Richard MacCutchan at 24-Mar-11 11:40am
I think you may be looking at this from the wrong point of view. You need to find a library that can handle encrypted PDF files. I am not certain, but I do not think you can just read it as a stream and pass it through a decryption process.
HimanshuJoshi at 23-Mar-11 15:46pm
Edited to remove unnecessary bold tag.
Dalek Dave at 24-Mar-11 9:37am
Edited for Grammar and Readability.
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Solution 2

You either:

(the fast route)
  • Use a library (free or commercial). As already suggested, Google would help you finding it


(the 'scenic' route)
  • Study the PDF specifications (freely available) and write your own code to do the job.
01.mandar at 24-Mar-11 9:02am
i have seen 2 library
zlib in c++
Pdfbox in java
coding for both mostly work on unencrypted pdf
my difficult is the pdf encryption
it just creates blank txt file when encrypted pdf is passed
Dalek Dave at 24-Mar-11 9:38am
Good Call.
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Solution 1

It sounds like what you need is an SDK that has APIs to allow you to open and extract text from a PDF file. I'm sure you will find lots by googling 'PDF SDK'.
01.mandar at 24-Mar-11 9:08am
i have seen some pdf sdk but they are mostly in .NET or for trial/demo basis
i will continue looking more for c++ or java

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