Protect a PDF with a password
Give a PDF an open password, so that anyone who wants to read it has to type the password first. The encryption happens on your device, and the password is never sent or stored.
Add one PDF to protect.
or drop a file here
Encrypted with AES-256. If you forget the password, this site cannot recover it either, so write it down.
Your PDF is handled inside this browser tab and is never uploaded.
How to use it
- Press ‘Choose a file’ and pick the PDF to lock.
- Type a password into ‘Password (at least 4 characters)’ and again into ‘Repeat password’. ‘Show’ reveals what you typed, and ‘Hide’ covers it again.
- Turn on ‘Also block printing, editing and copying’ to add permission limits on top of the password.
- Press ‘Protect PDF’, then ‘Download’. The locked copy is named like the original with -protected added.
What it does
AES-256 encryption
The file is encrypted with AES using a 256-bit key, applied by qpdf, an open-source PDF library that runs inside your browser. Without the password, PDF programs refuse to show the pages.
Typed twice, shown on request
The tool asks for the password twice and tells you if the two differ, since a typing slip would lock you out of your own file. ‘Show’ lets you read what you typed first. A password can have 4 to 64 characters.
Optional permission limits
With ‘Also block printing, editing and copying’ turned on, the file also carries flags that ask PDF software not to print it, change it or copy text out of it. Screen readers are still allowed to read it aloud.
Content left as it is
Only encryption is added. Pages, text, images, links and bookmarks are the same as in the original, so the file looks identical once the password has been entered.
A password nobody holds but you
The password lives in the page while you work and is neither uploaded nor saved. That keeps it private, and it also means nobody, this site included, can recover it for you.
Good to know
Lock a PDF before it travels: a tax form with a social security number, a lease with an ID copy attached, a pay stub going to a lender. An open password keeps the file unreadable to anyone who comes across the email or the shared link. Send the password by another route, such as a text message or a phone call, never in the same message as the file.
The lock is only as strong as the password. The tool accepts four characters, but a short word can be guessed. A phrase of several words, or a random string of twelve or more characters, is much safer. A forgotten password cannot be recovered, so keep it in a password manager or somewhere equally safe.
The printing, editing and copying limits are permission flags stored in the file, and each program decides whether to obey them. The tool also uses your one password both to open the file and as the file's owner password, so some programs will let whoever types it print or copy anyway. Treat the password as the protection and the flags as a request. A file that is already locked has to be unlocked first with Unlock PDF.
Questions and answers
How do I put a password on a PDF?
Open the file, type a password twice, press ‘Protect PDF’ and then ‘Download’. Your original is not changed; you get a locked copy.
Which encryption does Protect PDF use?
AES-256, which means AES with a 256-bit key, applied by the qpdf library inside your browser. Without the password the content cannot be read.
Can this site reset a forgotten password?
No. The tool never sends or stores the password, so neither this site nor anyone else can recover or reset it. Keep it with your other records or in a password manager.
Can I stop people from printing or copying the PDF?
The checkbox ‘Also block printing, editing and copying’ sets those permissions, all three together, but programs are not forced to obey them. The password is the dependable part.
What if the PDF already has a password?
The tool asks you to remove that password first, using Unlock PDF. Then you can lock the unlocked copy with the new password.
Are my PDF and password sent anywhere?
No. The encryption runs on your device, so the PDF and the password never reach a server. There is no account and no watermark.