Protect PDF: add a password & lock printing or copying
Free in-browser PDF password tool. Encrypt with AES-128, choose separate open and owner passwords, and restrict printing, copying, editing, annotations and form filling. Powered by @cantoo/pdf-lib — your PDF and password never leave your device.
Drop PDF files here
Or click to choose. Up to 10 files. Same password applies to all.
Choose PDFsUnchecked actions are blocked by the PDF reader when the file is opened with the user password. Opening with the owner password bypasses all restrictions.
When to password-protect a PDF
NDAs & contracts
Send a signed agreement that only the recipient can open with a pre-shared password.
Financial reports
Send earnings reports to investors with strict restrictions on copying or editing.
Medical & legal
Email lab results or case files to clients with HIPAA / GDPR-friendly protection.
Paid downloads
Distribute ebooks, courses or templates locked against print and copy.
How to protect a PDF with a password
Drop in the PDF
Drag & drop or click. Add up to 10 — the same password applies to all.
Set the open password
A strong open password is 12+ characters with letters, digits and symbols. The strength meter shows how good it is.
Pick permissions
Uncheck what you want to block — printing, copying, editing, annotations.
Click Protect & download
Each PDF is encrypted in your browser and downloaded individually or as a ZIP.
Protect PDF — frequently asked questions
Drop the PDF in, pick a strong open password, optionally set an owner password and permissions (block printing, copying, editing), then click Protect & download. The encrypted PDF is generated in your browser and downloaded directly.
AES-128 — the algorithm used by Adobe Acrobat and PDF readers since PDF 1.6. Strong enough to resist brute force when paired with a 12+ character password mixing letters, digits and symbols.
The user password (open password) is required to open the PDF at all. The owner password unlocks the permissions — without it, readers refuse to print, copy or edit. If you set only an owner password, anyone can open the file but the restrictions still apply.
No. Encryption runs entirely in your browser using @cantoo/pdf-lib (a maintained fork of pdf-lib). The PDF and the passwords never leave your device.
Yes. AES-128 encrypted PDFs open in Adobe Acrobat, Adobe Reader, macOS Preview, Foxit, Edge, Chrome's built-in viewer, Firefox's PDF.js, iOS Books and Android PDF readers. They all prompt for the password before showing content.
Yes — drop up to 10 PDFs and the same password is applied to all. Each output is downloaded individually or grouped into a ZIP.
About PDF encryption
PDF supports two password layers stacked on top of AES-128 encryption:
- User (open) password — required to open the PDF at all. Without it, no reader will show the contents.
- Owner password — required to bypass the permissions and edit / re-protect the file. Most readers honour the permissions even without the owner password.
How this tool encrypts
We load the PDF with @cantoo/pdf-lib, a community-maintained fork of pdf-lib that adds real encryption (the upstream library does not). The PDF object stream is encrypted with AES-128 keyed off your password; permissions are written into the encrypted document trailer. We save the file with useObjectStreams: false for maximum reader compatibility.
Privacy
The PDF, the passwords and the permissions are processed inside this browser tab. Nothing is transmitted; you can verify it in your browser's network tab while encrypting.
Password tips
- Use 12+ characters mixing upper / lower / digits / symbols.
- Never email a PDF and its password in the same message — use a different channel (a phone call, a separate text message).
- Store the password in a password manager so you don't lose access.