Open a protected PDF whose password you know
Published · Updated 3 min read
If you have the password of a PDF, you can save an unprotected copy of it, which opens directly. It is handy for a document you consult often, or to prepare it before sending. The tool guesses nothing: it uses the password you enter, in your browser.
What the tool does
Unlock PDF reads the document with the password supplied, decrypts its content and saves a copy that opens without a password. It does not search for a forgotten password and bypasses no protection: without the right password, it stops.
Supported protections
The tool handles the common PDF encryptions, with the opening password or the owner's.
| Encryption | Password entered | Result |
|---|---|---|
| RC4 40-bit | Opening | Unprotected copy |
| RC4 128-bit | Opening | Unprotected copy |
| AES 128-bit | Opening | Unprotected copy |
| AES 128-bit | Owner | Unprotected copy |
| AES 256-bit | Opening | Unprotected copy |
| AES 256-bit | Owner | Unprotected copy |
| AES 256-bit | Incorrect | Refused, with a message |
| AES 256-bit | None | Refused, with a message |
Opening password and owner password
A PDF can have two passwords. The opening one is requested to read the document. The owner's one only limits certain rights, such as printing or copying text, and asks for nothing on opening. A PDF whose rights alone are limited is saved without protection with nothing to enter.
What is kept
The text of the pages and their rendering are identical to those of the original document, and the document title stays readable. The weight stays close to the original: a 7.9 MB report weighs the same afterwards.
Messages when it does not work
- Incorrect password: "Mot de passe incorrect. Vérifiez les majuscules et les espaces."
- No password entered while the file asks for one: "Ce PDF demande son mot de passe actuel pour retirer la protection."
- Unsupported file: a message explains it and the file is not modified.
What is not supported
Some PDFs, often produced by Acrobat, store their structure in compressed blocks that are themselves encrypted. The tool detects this and answers that the file is not supported, without modifying it. Protections that do not rely on a password, such as certificate-based ones, are not supported either. A digital signature does not survive saving a copy.
Before and after
Keep the protected original until you have opened the copy. If the document is to be shared, remove unneeded information with Prepare a PDF before sharing it, then protect it again with Protect a PDF with a password, limits and good habits if needed. Remove a protection only on your own documents, or with their author's agreement.
For which cases
A protected statement you consult often, a document received with a password that you want to keep without protection, or a PDF to merge: the unprotected copy opens directly.
Check before using the copy
- Open the copy: no password should be requested.
- Count the pages and go through the document.
- Check that the text is selectable.
Frequently asked questions
- Can you remove the password of a PDF without knowing it?
- No. The tool guesses nothing and bypasses no protection: without the right password, it stops.
- Which encryptions are supported?
- The common PDF encryptions, 40- and 128-bit RC4 and 128- and 256-bit AES, with the opening password or the owner's.
- What is the difference between opening and owner passwords?
- The first is requested to read the document, the second only limits certain rights such as printing or copying.
- Is the document modified?
- The text and the rendering stay identical, and the weight stays close to the original.