Password-protect a PDF with real AES encryption (128 or 256-bit) — set open and owner passwords with strength guidance. Encryption runs entirely on your device.
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Processed privately in your browser — files never leave your device
Drop a PDF here or click to choose
Up to 25 files, 200.0 MB each — nothing is uploaded
Real AES encryption, not a viewer flag a reader can ignore. The strength of the result is the strength of the password — anyone who has it can open the file.
Input
payroll-summary.pdf with an open password and AES-256 selectedOutput
A PDF that cannot be opened or read without the password. Lose the password and the file is unrecoverable; there is no reset.Protect PDF applies genuine, standards-compliant PDF encryption — the kind every PDF viewer understands and enforces. Choose AES-128 (opens in every viewer ever made) or AES-256 (the strongest the format offers, for modern viewers), set the password that will be required to open the document, and optionally a separate owner password for full access.
The part that matters most: encryption happens in your browser. On upload-based services, your document and your chosen password both travel to someone else's server — an odd ritual for a confidentiality tool. Here, neither ever leaves your device; the password lives in this page's memory while you type it and nowhere else. It is never stored, logged, sent to analytics, or included in error reports.
One honest warning, stated in the tool as well: there is no recovery. A forgotten password on a well-encrypted PDF means a permanently locked document — store it in your password manager.
Drop a PDF into the tool.
Enter the open password and confirm it — the strength meter nudges you toward 12+ mixed characters.
Optionally set a separate owner password and choose AES-128 (maximum compatibility) or AES-256 (maximum strength).
Click Protect PDF and download the encrypted file.
Store the password in a password manager — it cannot be recovered.
Password strength is the real security boundary — a weak password undermines any encryption. Viewer enforcement of owner-password permissions varies by application. Lost passwords are unrecoverable by design. AES-256 output requires a reasonably modern PDF viewer.
Drop the PDF here, enter and confirm a password, and click Protect. The downloaded file demands that password in any PDF viewer. It's free, and both the file and the password stay on your device throughout.
AES-128 opens in every PDF viewer, including very old ones, and is still considered strong. AES-256 is the maximum the PDF format supports and the right choice when policy demands it — it requires a reasonably modern viewer (anything from the last decade).
There is no recovery — that's what real encryption means. Neither this tool nor anyone else can unlock the file without the password. Store it in a password manager at the moment you set it.
The open (user) password is required to view the document. The owner password grants full access and is what editing tools check before allowing changes. If you set only an open password, it serves both roles.
No. Encryption runs in your browser's memory. The password is never stored (not even in local storage), never logged, never included in analytics or error reports, and never appears in a URL.