Password-protect a PDF, or unlock one, online
Encrypt a PDF with an open password before emailing it, or remove the protection from a file whose password you know. Certyneo Reader computes the encryption in your browser: neither the document nor the password leaves your device, with no account and no limits.
Prefer an app? Download Certyneo Reader for free
The same PDF reader, installed on your computer: it opens your files offline, with no account, and can become your default PDF reader.
Does Windows show “Windows protected your PC”? That is the usual warning for a newly released app: click “More info”, check that the publisher is Certyneo, then click “Run anyway”.
Other systems and installers: macOS · Linux (AppImage) · Linux (.deb package for Debian and Ubuntu)
Windows (offline installer, MSI for managed fleets)
Windows (offline installer, x64) · Windows (offline installer, ARM64) · Windows (MSI for managed fleets)
Drop your PDF here
or choose a file on your computer, tablet or phone
Word, Excel, PowerPoint, text, RTF, images and HEIC photos are converted to PDF on your device.
100% local reading: the document is never sent over the internet.
How to put a password on a PDF in three steps
- 1
Open the PDF
Drag the file into the reader or pick it from your device. If it is already protected, enter its current password.
- 2
Choose the password
Enter the open password and, if needed, an owner password with permissions (printing, copying text, editing). Or choose "Remove the current password".
- 3
Save the file
The encrypted (or unlocked) PDF is generated on the spot. Share the password with your recipient through a different channel than the file.
Everything happens in your browser: the file never leaves your device. Open in the reader
Related tools and guides
- ↑ Free tools
- → Read a PDF online with nothing to install
- → Edit the text of a PDF
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- → Redact sensitive information in a PDF
- → Make a scanned PDF searchable with OCR
- → Compare two versions of a PDF
- → Check if a PDF has been modified
- → Rearrange the pages of a PDF
- → Merge several PDFs into one
- → Split a PDF into several files
- → Compress a PDF to send it by email
- → Fill in a PDF form
- → Convert JPG or PNG images to PDF
- → Add a watermark to a PDF
- → Add Bates numbering to a PDF
- → Create a fillable PDF form
- → Extract text from a PDF
- → Convert a PDF to Word or Excel
- → Process several PDFs at once
- → Crop a PDF or change its paper size
- → Add page numbers to a PDF
- → Add a page to a PDF
- → Delete pages from a PDF
- → Rotate the pages of a PDF
- → Extract pages from a PDF
- → Convert a Word document to PDF
- → Convert an Excel file to PDF
- → Convert a PowerPoint presentation to PDF
- → Convert an iPhone HEIC photo to PDF
- → Sign a PDF online, step by step
- → Handle your PDFs from Chrome with the Certyneo extension
Password-protecting a PDF: frequently asked questions
What level of encryption is used?
The PDF is encrypted with 256-bit AES, the strongest standard the PDF format provides, supported by every recent reader. Without the password, the content is unreadable.
Is the password sent to Certyneo?
No. Encryption, like decryption, is computed in your browser. Neither the file nor the password is transmitted, which also means Certyneo cannot recover it for you if you forget it.
How do I remove the password from a PDF?
Open the protected file, enter its password, then choose "Remove the current password" in the Protect tool: you get a copy with no password. You need to know the code; the tool does not crack a locked PDF.
Is a password enough to protect a contract?
It stops third parties from reading it, but proves neither who approved the document nor that it has not been altered. For that, have it signed with an electronic signature that complies with the eIDAS regulation.
Can I protect a PDF from my phone?
Yes. The tool works in recent browsers on Android, iPhone and iPad, with no app, using the same encryption as on a computer.
Does this PDF need to be signed?
Send it for electronic signature in minutes: your signers sign from their phone, without creating an account.
Get started with Certyneo for free