Protect PDF with password

Put an open password on a PDF, encrypt it with AES-256 and decide who may print, copy or edit it.

Drop your files here

.pdf · up to 300 MB

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How to Protect PDF

1
Drop your PDF in
Add one document or up to twenty. Your browser opens them; nothing is sent anywhere.
2
Type a password twice and pick permissions
The second field guards against a typo you would only notice tomorrow. Then choose whether printing, copying, editing and comments stay allowed once the file is open.
3
Download the encrypted file
Save the protected copy and share it. A batch comes back as one ZIP archive, every file locked with the same password.

What the password does

Encryption here is not a flag that a reader may politely honour. The whole content stream is encrypted with AES-256, the algorithm PDF 2.0 defines as revision 6, and without the password there is nothing to render: page text, fonts and images are ciphertext on disk. Acrobat, Preview, Chrome, Edge and every Android reader will ask for the password before showing a single line, and so will any script that tries to read the file with a library. That is the difference between a document that is protected and a document that merely asks nicely.

Permissions are a second, softer layer

Printing, copying, editing and commenting are stored as permission bits next to the password. Well-behaved readers honour them and grey out the matching menu items, and the bits survive being emailed around. They are enforced by the reader rather than by mathematics, though, so treat them as a clear statement of intent for colleagues, not as a barrier against a determined engineer. The open password is the part that holds.

The file and the password stay on your device

qpdf is compiled to WebAssembly and runs inside this page. Your document is read into browser memory, encrypted there and handed straight back as a download. The password is typed into a form that never makes a network request, so it is never transmitted, never logged and never stored. Close the tab and both are gone.

Frequently asked questions

Why AES-256 and not 128-bit encryption?

Because the older schemes are broken in practice. RC4 at 40 and 128 bits falls to tools that have been public for years, and AES-128 in PDF is tied to a weaker key derivation. AES-256 with revision 6 is the only option worth offering, so it is the only one here.

Is my PDF uploaded to a server?

No. The encryption engine is WebAssembly running in this tab, so the document never leaves your machine and there is no queue, no temporary copy and nothing for anyone to delete later. The same is true of the password you type.

What is the difference between a user and an owner password?

The user password opens the document: without it the file cannot be read at all. The owner password only governs permissions, so anyone can open the file but printing or copying may be blocked. Leave the owner field empty and both passwords are set to the same value.

What happens if I forget the password?

The document is lost. AES-256 has no back door and no recovery code, and we do not guess or brute-force passwords, on principle. Write it down in a password manager before you close this tab, and keep the original unencrypted file somewhere safe.

Will the file open in Acrobat, Preview and on Android?

Yes. AES-256 revision 6 is part of the PDF 2.0 standard and is supported by Acrobat 9 and later, Apple Preview, Chrome, Edge, Firefox and the common Android and iOS readers. Very old software from before 2009 may refuse it, which is the price of using strong encryption.

Can I take the password off again later?

Yes, with our PDF password removal tool, and only by typing the password yourself. It decrypts a document you can already open and lifts printing and copying limits. It does not recover or guess a password you have forgotten.

How strong are the printing and copying restrictions?

They are honoured by mainstream readers and are the right way to tell colleagues what you expect of the document. They are not cryptographic, so someone with the open password and the right software can work around them. Anything truly confidential belongs behind the open password.