Some files should not open for whoever finds them: a contract going out by email, a set of accounts, a medical letter, a scan of an ID document. This tool adds an open password to a PDF using AES-256 encryption, the current standard in the PDF specification, and lets you flag printing, copying and editing as blocked.

The work is done by qpdf, compiled to WebAssembly and running inside your browser. Neither the file nor the passwords you type leave your device. Nothing is uploaded, and there is no account or server that could keep a copy.

The two passwords

The open password is the one a reader asks for before showing the document. It is required, and it is the only thing standing between the file and anyone who has it, so pick something you would not mind being the only defence.

The owner password is optional and does a different job: it lifts the restrictions set by the switches below it. Leave it empty and the open password does both jobs. Set a separate one when you want people to read the file but not to remove the printing or copying block, and keep that owner password to yourself.

What the restriction switches do, and what they do not

Block printing, block copying and block editing set permission flags inside the encrypted file. Readers such as Acrobat, Preview, Chrome and Edge check them and grey out the matching commands. That is useful against casual copying and accidental printing.

It is not a lock. The flags are a request the viewer agrees to honour; the encryption protects the content from being read without a password, not from being printed once it is open. Anyone with the owner password can clear the flags, and a viewer written to ignore them will. If the content must never be printed, do not send it.

Always AES-256

The tool encrypts with 256-bit AES every time and offers no weaker option. The older RC4 modes in the PDF specification are broken, and 128-bit AES is deprecated in the current version of the standard. Every mainstream reader in current use opens AES-256 files.

One consequence to know before you click: there is no recovery. A PDF locked with a mistyped password cannot be opened by this site or by anything else without the password. The switch to show the passwords while typing exists for that reason; use it, and keep the original unlocked file somewhere safe.

What stays the same

Pages, text, fonts, images, bookmarks and form fields are preserved. qpdf encrypts the streams and strings inside the document without redrawing anything, so the protected copy looks identical when opened and text remains selectable unless you blocked copying.

The output is named after the input with -protected added, and its size is close to the original. The first run in a session fetches the qpdf engine, around 1.3 MB, from this site; the button says so while it loads, and later runs start at once.

Frequently asked questions