How to put a password on a PDF
Open Add a password, type the password twice, and press Lock it. The locked copy cannot be opened without that password.
Add a passwordFree. Nothing is uploaded.
How to do it
- Open Add a password and add the PDF.
- Leave Lock it with a password selected.
- Type the password, then type it again.
- Choose whether printing, copying and changes are allowed.
- Press Lock it and save the locked copy.
Choosing a password
The lock is AES-256, the strongest kind a PDF can carry, but a password anyone can guess undoes it. Avoid your date of birth or phone number alone if the file is going to people who know them. Send the password a different way from the file, such as a phone call or a separate message.
Write it down
Nobody can open the file without the password, us included. It is never stored or sent anywhere, so there is no reset. Keep the unlocked original, or the password, somewhere safe.
Only restricting printing and copying
Only restrict printing, copying and editing makes a file that opens for anyone, with those actions blocked in readers that respect the settings. Most do, but someone determined can switch them off, so use a real password for anything secret. To mark a copy as yours, add a watermark; to strip the author and other hidden details before sending, use Clean hidden data.
A worked example
You are emailing your salary slips to a loan agent. Open Add a password and add the PDFs. Type a password, such as three unrelated words with a number, and type it again. Leave Allow copying text unticked, and press Lock it. Send the files by email, then send the password by WhatsApp or a phone call, never in the same email as the files.
What the three permissions mean
Allow printing lets the person print the file once it is open. Allow copying text lets them select and copy its words. Allow changes and comments lets them edit it or add notes. They apply to someone who has opened the file, in readers that respect them, which includes Acrobat and Chrome. They are good for keeping a contract from being casually edited, not for keeping a secret.
Only restrict printing, copying and editing makes a file that opens for anyone, with those actions blocked in readers that respect them. It suits a brochure or a price list you want read but not reused, and never a document that must stay private, because a determined person can switch the blocks off.
Common mistakes
Using a password the person can guess from the document itself, such as the date of birth printed inside it, so the file is no safer than an envelope. Writing the password in the same email as the file. And locking the only copy: there is no reset, so keep the unlocked original and send a locked copy.
Questions people ask
Can I lock several PDFs with the same password?
Yes. Add them all; each is locked with the password you type.
Is my password sent to your server?
There is no server. The file is locked in your browser, and the password is never stored or sent.
How do I take the password off later?
Use Remove a password and type it in.
Will the person be able to open it on a phone?
Yes. Phone PDF viewers ask for the password and open it, like any locked bank statement.
Is AES-256 really secure?
The lock itself is the strongest a PDF can have. How safe the file really is depends on the password: a long one that nobody can guess is what makes it strong.
Can I change the password later?
Unlock the file with Remove a password using the old one, then lock the unlocked copy again with the new one.
Your file stays on your device. Foolscap does the work inside your browser, so nothing is uploaded and there is nothing for anyone to keep. How you can check