PDF Password Remover

Discussion & Solutions
1

Hello. i am looking to remove password from one of the pdf files. It’s a book and I don’t know the password length, characters used. is there a way to get the password or remove the password from this file?

The file can be accessed from the following URL

Thanks

2

Two password types. One’s a joke, one’s the wall. Can you open the file? Yes = 30 seconds. No = encryption rabbit hole. Here’s the difference.

🔓 OWNER-PASSWORD FIX (30 sec — permissions lock)

File opens but you can’t copy/edit? That’s owner-password. This is a joke to remove:

qpdf --decrypt input.pdf output.pdf

Done. New file has zero restrictions.

Setup:

  • qpdf GitHub — grab the release for your OS (Windows/Mac/Linux)
  • 2-min install, one command, zero dependencies

That’s the loot. Go read your book.

🔐 USER-PASSWORD ENCRYPTION (the actual lockpick)

File won’t open at all? That’s encryption. Check what you’re up against:

pdfinfo your-file.pdf | grep Encryption

Your results:

Result Feasibility Time
RC4 / 40-bit / 128-bit :white_check_mark: Crackable Hours
AES-128 :warning: Wordlist-dependent Hours–Never
AES-256 :cross_mark: Don’t bother Age of universe

If it’s RC4 or AES-128, here’s the play:

Extract the hash:

python3 pdf2john.py your-file.pdf > hash.txt

Grab Hashcat (free GPU tool). Crack it:

hashcat -m 10500 hash.txt rockyou.txt

:light_bulb: The move: rockyou.txt is 14M common passwords. RTX 4090 burns through it in 15-30 min. Password in there = you win. Not in there = go to next step.

If rockyou doesn’t work: Custom wordlist time. The password is usually:

  • Book ISBN
  • Truncated title
  • Publisher default (sometimes leaked, try it anyway)
  • “password” / “123456” (try these first lol)

Build a wordlist with guesses from whoever made this PDF. Throw it at Hashcat.

:light_bulb: The hard truth: Publisher PDFs (O’Reilly, Springer) sometimes use weak passwords because DRM is legal lock, not cryptographic lock. AES-128 + right wordlist = 25-40% shot. AES-256 = nope.

Last resort: Email the publisher. “Lost my password.” They usually just send the unencrypted version. Yeah it’s not as fun as cracking it, but faster.

🛠️ QUICK SETUP CHECKLIST

All cross-platform. All free. All tested 2024.

the simple-pimple: File opens = qpdf one-liner done. File locked = check encryption type, then hashcat + wordlist IF it’s RC4/AES-128. AES-256? Contact the publisher. That’s the whole game.

:high_voltage: Go get your book.

3

imageThank you so much. You are life saver. Thanks again and stay bless. Its AES-128 Encryption