How this tool works
Protect PDF: a practical guide
Uses the bundled PDF encryption library and refuses to produce a result if encryption is unavailable. Both password fields must match; no default password is supplied.
Steps to use this tool
- Select a readable PDF.
- Enter matching password and confirmation values.
- Protect the file and verify password access in a viewer.
Tested example — 19 October 2026
The encrypted sample opens with its test password and rejects an incorrect password.
Selected sample: sample.pdf (2421 bytes, 2 pages).
Measured output: sample-protected.pdf — 3255 bytes; 2 PDF pages.
Test environment: Node + native canvas + actual site-ui.js form integration in LinkeDOM Representative sample; inspect your own output.
Check the result
Close the output and reopen it in a separate PDF viewer. Confirm that the correct password works and that an incorrect password is rejected.
Files and privacy
The public tool processes selected documents in your browser. It does not send document bytes to a conversion server. The page and its bundled libraries still download from this website. Keep the original, use an up-to-date browser and inspect your output before sharing it. See the privacy policy for hosting and support information.
If processing fails
An empty password or mismatched confirmation is refused. If the source already has encryption, open an authorized readable copy before applying the new protection.
Implementation notes and sample evidence updated 2026-10-19. These notes describe the supported operation and its limits.
Check the local-processing claim in your browser’s Network panel.