What this tool does
- AES-256 or AES-128 — pick maximum strength, or maximum compatibility with older readers
- Open password — the file cannot be viewed at all without it
- Owner password — optional, separate password that controls permissions
- Permission switches — allow or block printing, copying text, editing, annotating and form filling
- Password strength meter — so you do not encrypt a document behind
1234 - Batch — protect several PDFs with the same settings at once
Why this one is different
Most “protect PDF” sites upload your document to a server to encrypt it, which means handing both the confidential file and its password to a third party — exactly the thing you were trying to prevent. This tool does the encryption in your browser with JavaScript. The file and the password never go anywhere.
Open password vs owner password
A PDF has two separate passwords. The user (open) password is required to decrypt and view the file. The owner password unlocks full permissions; a reader who opens the file with only the user password is restricted to whatever you allowed. If you set only an owner password, anyone can open the document but is limited — useful for a read-only handout. Note that permission flags are honoured by well-behaved readers rather than enforced by cryptography; the open password is the part that genuinely protects the content.
Frequently asked questions
Are my PDFs or passwords uploaded anywhere?
No — the encryption happens in your browser. The document and the password you type never leave your device, which is the whole point of doing it locally.
What encryption is used?
AES-256 by default (security handler revision 5), which Acrobat 9 and later, current browsers and every mainstream reader open. AES-128 is offered as well for very old software — it is still a strong cipher, just a shorter key.
What if I forget the password?
The file cannot be opened — there is no backdoor and we cannot recover it. Store the password in a password manager before you close the tab.
Can I stop someone printing or copying text?
You can set those permission flags, and mainstream readers respect them. They are a policy signal rather than cryptographic enforcement, so for genuinely sensitive material rely on the open password.
Can I protect several files at once?
Yes — add multiple PDFs and all of them are encrypted with the same password and permissions, then downloaded as a ZIP.