Protect a PDF with a password
Add a password to a PDF using real AES-256 encryption — the same standard Adobe Acrobat uses. Optionally restrict printing or copying. Both the document and the password stay on your device at all times.
100% private: files are processed in your browser and never uploaded to any server.
How it works
- Drop the PDF you want to protect into the box above.
- Type a password (twice), and untick printing or copying if you want to restrict them.
- Click “Protect PDF” and download the encrypted file.
What a password on a PDF actually does
Adding a password encrypts the PDF: its contents are scrambled with a key derived from your password, so without that password the file is unreadable gibberish, even to someone who has the file. This is real cryptographic protection, not a "please do not open" flag. It is the right tool when you need to email a sensitive document, store one in the cloud, or hand over a file that only the intended person should be able to read.
AES-256, the same standard Acrobat uses
Pdfect encrypts with AES-256, the strongest encryption defined by the PDF standard and the same algorithm used by Adobe Acrobat and by governments for classified material. In practice it cannot be broken by guessing the key — the security rests entirely on the strength of your password. A long passphrase is far safer than a short complex one, so favour length.
Encryption that never leaves your device
This is where doing it client-side matters most. Many "protect PDF" sites ask you to upload the very document you are trying to keep private, along with the password, to a server you do not control — which rather defeats the purpose. Pdfect runs the encryption in your browser using a WebAssembly build of qpdf, so the file and the password never leave your device. There is nothing to intercept and no server that ever sees your secret.
Print and copy restrictions
Beyond the open password, you can set permission flags that ask compliant readers to disable printing or text copying. These are useful for discouraging casual reuse, but be aware they are advisory: a determined user who can open the document can bypass them with the right software. For genuine confidentiality, the open password is what matters.
Frequently asked questions
How strong is the encryption?
The file is encrypted with AES-256, the strongest encryption defined by the PDF standard and the same one used by Adobe Acrobat. Without the password, the content cannot be read.
Is my password sent to your server?
No. The encryption runs in your browser via WebAssembly — the password and the document never leave your device. We could not see them even if we wanted to.
What happens if I forget the password?
There is no recovery. AES-256 cannot be cracked in practice, so store the password somewhere safe — a password manager is ideal.
What do the printing and copying restrictions do?
They set PDF permission flags that compliant readers honor: the document opens with the password but refuses to print or to copy text. Note that permission flags are advisory — a determined user with the open password can bypass them.
Can the recipient open it on any device?
Yes. It is standard PDF encryption, so any compliant PDF reader on any platform will prompt for the password and open the file.