What is Open PDF?
A standard PDF anyone who has the file can open — fine for sharing publicly, risky for contracts, invoices, medical or HR documents.
Encrypt PDF
Protect a PDF with a password
Preparing the tool…
The tool could not be loaded. Check your connection and try again.
Encrypt PDF
Drop your PDF here
or click to browse — one PDF at a time
Use a password you can remember. You will need it to open the protected PDF.
Choose a file to get started.
How to password-protect a PDF
Choose a file
Drag your file into the box or click to browse.
Process your file
Check the options, then click the main button to start.
Download the result
When processing finishes, save the result using the download button.
Frequently asked questions
How strong is the encryption?
AES-256, the same algorithm used by modern PDF applications. There is no weak-encryption option here — the tool applies strong encryption only.
What happens to my password?
It is used only for your confirmed upload, inside that private processing job. It is deleted when the job ends — not logged, not saved in your browser, and not placed in URLs or analytics.
Can the tool recover my password later?
No. The encrypted result opens only with your password, and we cannot restore access.
How many files can I encrypt per day?
Free use is limited to 5 conversions per day, shared across our upload-based tools — there is no unlimited option. Files up to 25 MB and 200 pages.
Does the download show a preview?
No. The encrypted result is offered as a direct download; opening it requires the password, so the page does not attempt an inline preview.
What if my PDF already has a password?
The tool rejects already-encrypted files. Decrypt it first with our Decrypt PDF tool, then apply the new password.
Will encrypting invalidate existing digital signatures?
Rewriting a PDF can invalidate digital signatures applied earlier. If the original is signed, keep it and encrypt a copy.
PDF encryption with AES-256
Here is what each format is for, and when converting open PDFs into password-protected files is the right move.
What is Encrypted PDF?
The same document sealed with AES-256: viewers demand the password before rendering a single page, so the contents stay unreadable without it.
When you need it
Encrypt whenever a PDF leaves your control and contains anything private — contracts, statements, IDs. Encryption protects the file itself; it does not certify the contents, and it is no substitute for simply not sending sensitive data at all.