Add an opening password to a PDF
Without the password, the file won't open in any program — the tool confirms this by reopening its own result before releasing the download.
Drag a PDF here, or click to choose
PDF, up to 50 MB
Local processing: your file never leaves your computer.
- Does:Without the password, the file won't open in any program — the tool confirms this by reopening its own result before releasing the download.
- Processes:Your PDF is processed entirely in your browser — nothing is uploaded to a server.
- Doesn't do:The password never leaves your browser: nothing is sent over the network. Save the opening password before downloading the file — it isn't stored anywhere and there's no way to recover it afterward.
Adding a password to a PDF before sending it
A document with sensitive information — a contract, a tax form, a medical report — sometimes needs to leave your computer before it's the right moment for just anyone to open it: attached to an email, saved in a shared folder, sent through a channel that isn't fully trusted. Adding an opening password solves that specific problem: whoever doesn't have the password can't read the content, no matter how the file ends up in the wrong hands.
This tool does only that: you upload a PDF, set a password, and it hands back a protected copy — nothing to install, and the file never leaves your computer, because all the encryption runs inside the browser, using a real PDF implementation (qpdf compiled to WebAssembly), not a simplified reimplementation from scratch. The original file you uploaded is never altered; what the tool generates is a new, encrypted copy, leaving the original exactly as it was.
Two passwords, two different purposes
The tool separates two things that are often confused. The opening password is required and is the real protection: without it, the PDF's content is unreadable in any program, full stop. The permissions password is optional and does something far more limited — it lets you restrict actions like printing, copying text, or editing the document. Those restrictions are a convention a PDF reader chooses to respect, not a cryptographic lock: widely available free tools remove that kind of restriction in seconds. The interface makes this explicit right next to the field itself, not just here: anyone who needs to stop content from being read by the wrong person depends on the opening password, not on permission restrictions.
What the chosen encryption actually means
The only encryption option offered is AES-256, the strongest standard the PDF format currently supports. The tool doesn't offer RC4 or 128-bit without AES — those are considered weak today, breakable with common tools, and don't make sense for someone who specifically came to a PDF-protection tool looking for real security. There's also no option to pick a weaker standard "just for compatibility": the point here is to protect, not to trade away protection for convenience.
Verification before handing over the file
After applying the password, the tool doesn't hand over the result directly. It reopens the file it just generated twice: once with no password at all, which needs to fail — confirming the file is actually encrypted, not just that it exists — and once with the password you entered, which needs to work — confirming that password really opens the result. Only once both checks pass does the download button appear. If either one fails, the tool shows an error and delivers nothing: a PDF that looks protected but isn't is worse than the tool simply not working — in that scenario, whoever trusts the file might share it believing it's secure.
Before you generate: save the password
There's no password recovery here, and that's deliberate. The password is never sent to any server or stored anywhere — not by this tool, not by whoever maintains it. That means losing the password to an AES-256 protected PDF is final: there's no secret command, no support contact, no other tool capable of opening the file without it. Before downloading the result, it's worth confirming the password is saved somewhere safe and recoverable — a password manager, for example — because the protected file itself won't help you remember what you typed.
What this tool doesn't do
It doesn't remove a password from a PDF that's already protected — a file like that is detected on upload and isn't processed, to avoid risking an overwrite of existing protection without knowing the current password. It doesn't open PDFs protected by someone else. It doesn't recover a forgotten password, whether from a PDF generated here or anywhere else. And it doesn't stop someone who has the opening password from forwarding the file, taking screenshots of the content, or sharing the password with someone else — the protection is about opening the file, not about what happens after it's open.
Frequently asked questions
What's the difference between the opening password and the permissions password?
The opening password is the real protection: without it, the PDF's content isn't readable by anyone, in any program. The permissions password only controls restrictions like blocking printing or copying text — restrictions a PDF reader chooses to respect, not a cryptographic lock. Free tools exist that remove those restrictions in seconds, with or without the permissions password. If the goal is to keep someone from reading the content, the opening password is what matters.
I forgot the password I set on a PDF. How do I recover it?
There's no way to. The password isn't stored anywhere — not by this tool, not by anyone — and AES-256 encryption has no backdoor for recovery. A protected PDF with a forgotten password is, in practice, a lost PDF: the only way to access the content again is to have the original, password-free file saved somewhere.
Why does the tool check the file after generating it, instead of just handing it over?
Because a PDF that looks protected but doesn't actually open with the right password (or worse, isn't really protected at all) is the worst possible outcome here — worse than the tool simply failing. So after applying the password, the tool reopens the file it just generated with no password at all (which needs to fail) and again with the password you entered (which needs to work). It only delivers the file if both checks pass; if either fails, it shows an error and delivers nothing.
Why only AES-256, with no option for RC4 or 128-bit?
RC4 and 128-bit encryption without AES are considered weak today — tools exist that break that protection quickly. Since the reason someone lands on this tool is to protect content for real, offering a weak standard with no need to would just create a false sense of security. AES-256 is the strongest standard the PDF format currently supports.
Can a PDF that already has a password get a second layer of protection?
No. This tool detects an already-protected PDF when you add the file and doesn't try to open it, remove its existing protection, or replace it with a new one. A password-protected PDF needs to have that password removed first (in another program, with the correct password) before it can be processed here.
Related tools
- Convert images to PDFControls page order, paper size, and margins — built for pages photographed with a phone, not for PDFs that already exist.
- Merge PDF filesCopies pages from the original files without turning them into images, so text and vector content stay exactly as they were.
- Split PDF pagesProduces a single file with the range you choose, several files by range, or one file per page — you pick the mode.
- Rotate and reorder PDF pagesFixes orientation and order on the same screen, with undo and a full reset to the original available at any point before you generate the result.