If you have know the password, and want to remove the password, please use this free software,PdfCrypt
PDFCrack source code has been released over a month, but there is still no windows binary version, so I decide to do it, and it come to the world.
I do noting, but use Cygwin to compile PDFCrack under Windows XP
If you want source code, please download from PDFCrack project page.
Features available in this release (check TODO for features that might come):
* Both owner- and user-passwords with the Standard Security Handler, rev 2 & 3.
* Search by wordlist
* Search by bruteforcing with specific charset
* Optimized search for owner-password when user-password is known (or empty)
* Extremely simple permutations of passwords (makes first letter uppercase)
– currently only useful for bruteforcing with charsets:
* Auto-save when interrupted (Ctrl-C or send SIGINT to the process)
* Loading saved state
– currently only for bruteforcing with charsets:
* Minimum length of password to start at
* Maximum length of password to try
Sort your wordlist by length for best performance and consider that almost
all passwords in PDFs are in iso latin 1 so use the correct character encoding
in your terminal and/or wordlist when using special characters.
This tool can not decrypt a Password Protected PDF.
Look up the pdftk toolkit which can do that, when you know the password.