Password Protect a PDF
Add a password so only the people you choose can open the document. Encrypted with 256-bit AES.
Encryption runs on our server, so the file and password are uploaded over an encrypted connection. Both are deleted as soon as your download finishes, and the password is never stored.
Your processed file downloads automatically when it is ready.
How to password protect a PDF
A password protected PDF asks for a password before it will open, in every reader on every device. It is the simplest way to send something confidential by email, and if you have been looking up how to encrypt a PDF without buying software, this is it.
- 1
Choose your PDF
Drag the file in or click to browse. Anything you can open normally can be encrypted.
- 2
Set a PDF password
Type it twice so a typo cannot lock you out of your own document. The strength indicator shows how well it would hold up.
- 3
Download the locked file
Press Lock and the encrypted copy downloads. Your original stays unprotected on your device, so keep it if you still need it.
When a document needs a lock
Anything you would not want read by whoever happens to see the inbox.
Payslips and statements
Send financial documents that stay unreadable if the email lands in the wrong place.
Contracts
Password protect a PDF so only the people meant to read the terms can open it.
Medical records
Protect health information that has to travel by email.
Identity documents
Add password protection for PDF scans when a form asks you to send a copy of your ID.
Internal reports
Circulate results or plans that should not spread beyond a specific group.
Client deliverables
Send finished work that only the paying client should be able to open.
Shared drives
Keep a password protected PDF readable only to the handful of people who were given the key.
Board papers
Encrypt a PDF file circulated before a meeting where the contents are not yet public.
What a PDF password actually protects
PDF encryption is genuine cryptography, not a flag telling readers to behave. Understanding which kind you are applying explains what it will and will not stop.
How to password protect a PDF here
Upload the document, choose a password, download the encrypted copy. Anyone opening it afterwards has to enter that password, and it is free to password protect PDF documents here with no account and no watermark.
The encryption runs on our server, because it needs software a browser cannot provide. Both the file and the password are deleted the moment your download finishes, and the password is never written to disk.
Two kinds of PDF password
An open password, sometimes called a user password, is what this tool sets. Without it the file cannot be decrypted at all, so nothing can be read, printed or copied.
An owner password is different. It leaves the document readable by anyone and only asks readers to restrict printing or copying. Most readers honour that request and plenty of tools ignore it entirely, which is why it is closer to a polite notice than protection.
If you want the document genuinely private, the open password is the one that matters.
How strong is 256-bit AES
AES-256 is the same standard used for classified government material and full-disk encryption. There is no practical attack against the algorithm itself, and there will not be one in your lifetime.
The weak point is never the maths, it is the password. Encryption turns your password into the key, so a document locked with a dictionary word is opened by a program trying dictionary words. Everything about the file security therefore rests on what you type.
What people search for
How to lock a PDF. How to lock PDF file. Lock PDF. PDF password. PDF password protect. PDF password protection. How do I encrypt a PDF. How to encrypt a PDF file. Encrypt PDF. Encrypt PDF file.
The variants pile up because nobody agrees on the verb: how to password protect PDF, password protect a PDF, password protect PDF document, password protect PDF doc, password protection for PDF, password protect PDF free. They all describe this one operation.
Sending the password safely
Emailing a locked file and its password together is the mistake almost everybody makes. Anyone who intercepts the message gets both halves, and the encryption has bought you nothing.
Send the document one way and the password another. Text the password, say it on a call, or share it through a password manager. The protection only holds while the two travel separately.
There is no recovery
Forget the password and the file is gone. Not difficult to open, gone. We cannot recover it, no support ticket will help, and any service claiming otherwise is either guessing common passwords or lying.
Store it somewhere durable before you send the file anywhere. If you later want the protection removed and you still know the password, Unlock PDF takes it back off.
Choosing a good password
The encryption is strong. Whether the file is actually safe comes down to the password.
- Length beats complexity. Several unrelated words are both stronger and easier to remember than a short string of symbols.
- Never reuse a password you use elsewhere, since this one has to be shared with whoever receives the file.
- Send the password separately from the document, by text or a call, not in the same email.
- Write it down somewhere safe before you send anything. A forgotten password cannot be recovered by anyone, including us.
- Avoid names, dates and anything guessable from the document itself.
- Keep your unencrypted original. The locked file is a separate download, and you will want the plain copy for your own use.
Questions, answered
How the encryption works and what it does and does not cover.
Upload the PDF, type the password you want, and download the protected copy. Anyone opening it afterwards has to enter that password. The file is encrypted with 256-bit AES.
Related tools
Other things you can do here without signing up.