Password protect a PDF
Password protect a PDF for free in your browser, with no upload and no sign-up. Type a password, optionally add a separate owner password, choose whether printing and copying are allowed, and save an AES-256 encrypted copy.
Type a password, choose what a reader is allowed to do, and save an encrypted copy.
In detail
Protect PDF encrypts a document in your browser with AES-256, the only cipher ISO 32000-2 still recommends. You type a user password, which is what a reader is asked for, and optionally an owner password, which grants full rights and overrides the restrictions. AES-128 is offered for readers older than Acrobat 7; the broken RC4 ciphers are not offered at all.
The permission switches — printing, copying, editing, commenting, forms, page assembly and screen-reader access — are written into the encrypted document as flags. A conforming reader obeys them; a program that already has the password can ignore them. The encryption is the part that holds the file shut, and the password never leaves this tab, so a forgotten one cannot be recovered by anyone.
Password protect a PDF at a glance
- Input
- One PDF that is not already encrypted
- Output
- The same PDF, encrypted, with a password needed to open it
- What it does
- AES-256 encryption by default
- AES-128 for readers older than Acrobat 7
- Separate user and owner passwords
- Printing, copying, editing and form permissions
- An honest password strength reading in bits
- Refuses a PDF that is already encrypted
- Leaves the document's own metadata alone
- Who it is for
- Anyone emailing a contract, a payslip, a medical record or a bank statement.
- Limits
- Adds a password; it cannot remove one, and an already encrypted PDF is refused.
- Permissions are advisory: any program that has the password can ignore them.
- A forgotten password cannot be recovered by anyone, including File4Edit.
- Needs the browser's Web Crypto API, which supplies the random encryption key.
- Privacy
- Runs entirely in your browser: the PDF is never uploaded, and the password is never sent or stored anywhere.
How to password protect a PDF
- Open the PDF Drop the file onto the page. Its first page renders, and the summary says how many pages it has and what size a reader shows them at.
- Type the password Type the password a reader will be asked for, then type it again to confirm. A strength reading updates as you type, and nothing can be saved until the two fields match.
- Add an owner password Optional, and the only thing that makes the permissions mean anything: leave it blank and it becomes a copy of the password above, so everyone who can open the file holds owner rights.
- Choose what a reader may do Printing at full quality, at reduced quality or not at all, then switches for copying, editing, commenting, filling forms, reordering pages and screen-reader extraction.
- Protect and save Press Protect and save. The document is encrypted with AES-256 and handed straight back as a download, with the original file on your disk untouched.
Password protect a PDF: common questions
Is this real encryption, or just a flag in the file?
It is real encryption. Every string and stream in the document is ciphered under a key derived from your password, which is the AES-256 security handler ISO 32000-2 specifies, so a reader without the password has nothing to show. The permission settings are the part that is only a flag.
What is the difference between the password and the owner password?
The first one opens the document; the owner password opens it with full rights and overrides every restriction. If you leave the owner password blank it becomes a copy of the first one, which means anyone who can open the file also holds owner rights and the permissions stop mattering. Set a different owner password whenever the restrictions are the point.
Can the permissions actually stop someone printing or copying?
Only as far as their reader chooses to obey them. Permissions are flags written inside the encrypted document, and a conforming reader such as Acrobat honors them, but nothing in the file prevents a program from ignoring them once it has the password. Treat them as a clear statement of intent rather than as enforcement.
Can File4Edit remove a password from a PDF?
No. This tool adds a password and cannot take one off. A PDF that is already encrypted is refused with a message rather than opened, and if you have forgotten the password to your own document nothing here will recover it.
What happens if I forget the password?
The file is lost. Nothing is stored anywhere — the password exists only in this tab while you type it, is never sent and is never saved — so there is no reset link and no recovery. Write it down somewhere safe before you close the tab.