Password-protect a PDF
Set a password to open the file, optionally restrict printing, editing and copying, and download an encrypted PDF.
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What it does
Protect PDF, explained
Protect PDF encrypts a file with AES-256 so it can't be opened without the password you set. Encryption runs in your browser: neither the PDF nor the password is sent to PDFBetter, which also means nobody at PDFBetter can recover a forgotten password.
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There are two separate settings. The open password (user password) is the real lock: without it the content can't be read. Permissions (owner password) limit printing, editing, copying, annotating and form filling for people who can open the file, but they rely on the PDF viewer to respect them. Mainstream readers do; some tools ignore them.
Use an open password for tax returns, medical records or payroll you must email. Use permissions alone when the content isn't secret but you want to discourage edits, for example a published price list. To reverse it with the password, use Unlock PDF. To remove content rather than lock it, use Redact PDF.
How to do it
Password-protect a PDF in 4 steps
1Your PDF
2Set a password
3Opens only with it
- 1
Add your PDF
Drop in the file. It is read and encrypted on your device.
- 2
Set an open password
Type a strong password and store it somewhere safe. Share it with recipients through a different channel than the file.
- 3
Choose permissions (optional)
Untick printing, modifying, copying, annotating or form filling, and set an owner password that is different from the open password.
- 4
Download
The encrypted PDF downloads immediately. Open it once to confirm the password works.
Example
Before and after
A completed W-9 with a Social Security number that a contractor needs to email to a new client.
An AES-256 encrypted PDF that asks for a password on open; the password is sent to the client by text message, separately from the email.
Settings & formats
What you can control
- Open password
- Required to open and read the file. Encrypted with AES-256.
- Permissions
- Allow or block printing, modifying, copying, annotating and filling forms.
- Owner password
- Needed to change the permissions later. Use a different value from the open password.
Input
Output
Good to know before you start
- Permission restrictions are enforced by the viewer, not by encryption; software that ignores them can still print or copy once the file is open.
- AES-256 needs a reasonably modern PDF reader; very old readers may not open the file.
- A forgotten password cannot be recovered or reset by PDFBetter, because it never leaves your device.
- An already-encrypted PDF must be unlocked before you set new passwords.
If something goes wrong
If something goes wrong
- The recipient says the password doesn't work
- Check for a trailing space or a keyboard layout difference, and confirm you sent the open password, not the owner password.
- The recipient can still print
- Their viewer may ignore permission flags. If printing must be impossible, don't send the file; share a view-only link instead.
Protect PDF: questions people ask
What is the difference between an open password and permissions?
The open password encrypts the content so it can't be read without it. Permissions only ask the viewer to block actions like printing or copying after the file is open.
Is my password sent to PDFBetter?
No. Encryption happens in your browser and the password is never transmitted.
Can I protect a PDF that has fillable fields?
Yes. Leave form filling allowed in permissions so recipients can still type into the fields after opening.
Does protecting a PDF stop screenshots?
No PDF setting can stop screenshots or photos of the screen. Encryption controls who can open the file, not what they do with what they see.
Can I add a password when downloading from the editor?
Download the edited file, then run it through Protect PDF. Protecting last keeps your edits and the encryption together.