Encrypt PDF
Password protect a PDF in your browser with 256-bit AES. Set an open password, an owner password and print or copy permissions. No upload needed.
Upload PDF File
Read the full guide: How to Password Protect a PDF for Free in Your Browser
About This Tool
Encrypt PDF locks a PDF behind a password. Type a User Password, which anyone must enter before the file will open, add an Owner Password if you also want to restrict actions such as printing or copying, then click Encrypt PDF and download the copy saved with _encrypted in its name.
The work is done by qpdf, an open-source PDF library compiled to WebAssembly, and it always applies 256-bit AES; there is no weaker setting to pick by mistake. At least one password is required. The seven permission boxes (printing, modifying, copying, annotating, filling forms, accessibility and assembly) start ticked and are only written into the file when an owner password is set and differs from the user password. In qpdf, switching off Allow Modifying also switches off annotating, form filling and assembly.
Permissions are requests that PDF software may or may not honour, and with an owner password alone the file still opens for anyone. Only the user password keeps the content from being read. The encryption is only as strong as that password, so use a long passphrase, and keep an unencrypted master copy, because a lost password cannot be recovered.
Encryption runs in your browser tab; the PDF and the passwords you type are not uploaded, and the qpdf engine is fetched from this site the first time you use it. When you send an unpublished report or quality document to a partner, keep the master in your own document system and pass the password on by phone or another channel, never in the same email as the file.
Step-by-step instructions and common mistakes: How to Password Protect a PDF for Free in Your Browser.
How to Use
Add the PDF
Drop one PDF on the upload area or click to browse.
Set the passwords
Under Password Settings, type a User Password (to open document) and, if needed, a different Owner Password (to change permissions). The eye button shows what you typed.
Choose permissions
Under Document Permissions, untick any action you want to restrict. These settings only apply when a separate owner password is set.
Encrypt and download
Click Encrypt PDF, download the _encrypted copy and open it once to check that it asks for the password.
Use Cases
Emailing a confidential report
Encrypt a technical report before it goes to a contract manufacturer, and phone the password through separately.
Personal documents
Protect payslips, HR letters or medical correspondence so that only someone holding the password can open them.
Discouraging casual copying
Add an owner password and switch off copying or printing on a reference document, accepting that some software ignores these flags.
Files on shared storage
Keep a protected copy on a shared drive or USB key where other people may be able to browse the folders.
Frequently Asked Questions
What encryption does Encrypt PDF use?
256-bit AES, applied by the open-source qpdf library running in your browser. There is no option for older or weaker encryption.
Do I need both a user and an owner password?
No, but you need at least one. A user password alone stops the file opening without it. An owner password alone leaves the file readable by anyone and only records permission restrictions.
Why did my permission settings have no effect?
Permissions are only written when an owner password is set and it is different from the user password. If the two match, or you set only a user password, anyone who opens the file gets full rights.
Can I encrypt a PDF that already needs a password to open?
Remove the existing password first with Decrypt PDF, using the password you have, then encrypt the unlocked copy. To change rules on a file you control, Change Permissions is another route.
Can a forgotten password be recovered?
No. Passwords are never sent to or stored by this site, so store an open master copy in a safe place before encrypting.