About Protect PDF
Lock Your PDF With a Password in Seconds
Contracts, payslips, medical records and tax returns often travel by email or sit in shared folders. A password makes sure only the people you choose can open them. Our free Protect PDF tool encrypts your document with AES-256, the strongest encryption the PDF standard offers and the same level used by Adobe Acrobat.
Encrypted on Your Device, Never Uploaded
Most online PDF protectors ask you to upload the very file you want to keep private, together with its new password. PDFMerger.io does the encryption inside your browser. The document and the password stay on your device from start to finish, so there is nothing on a server to leak.
Control What People Can Do
- Open password: nobody can view the PDF without it.
- Block printing: stop the file from being printed.
- Block copying: stop text and images from being copied out.
- Block editing: stop pages, forms and annotations from being changed.
Add an optional owner password if you want to lift these restrictions later.
Works With Every PDF Reader
The protected file opens in Adobe Acrobat, Apple Preview, Chrome, Edge, Firefox and any modern PDF app. Readers ask for the password before showing a single page.