Hello again,
How do I decrypt a PDF file which has password protection but which doesn't prevent you reading the contents?
In other words, I have an /Encrypt object in my trailer, and that has:
/Filter /Standard /R 2 /O (some string) /U (some string) /P -12 /V 1 /Length 40
I know I can read this without a password, and the very excellent A-PDF text extractor gets the text out fine. I just need to know how to do this myself!
Once again, all help gratefully received.
Richard
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angel622
As i know,your pdf files are protected by pdf restriction ,which means you can open the pdf but couldn't copy,edit,print,right?I don't know how to decrypt a pdf file in c# ,but i do in this way,i use advanced pdf password remover 5.0 which can remove pdf restriction in seconds. Also,if it is not pdf restriction but pdf password,you can use pdf password recovery to remove your pdf password.
mark stephens
If you have the password, you can remove the encryption with lots of tools - Itext has an example so you can probably use ISharp to do this.
If you do not have the password, you would need a password cracking program to work it out essentially by brute force.
There is a blog article explaining passwords in more detail at http://pdf.jpedal.org/java-pdf-blog/bid/27446/Understanding-the-PDF-file-format-PDF-password-protection