PDF password-protection

AES-256 encryption: the strongest available algorithm for password-protecting PDF files. Processing is entirely client side - your document never leaves your device.

Click here or drag and drop your PDF

Strong PDF encryption, processed locally. Set the open password in your browser and download the protected file when it is ready. The document is encrypted locally with AES-256 before the new copy is saved.
- AES-256 encryption for the document content.
- No upload step before protection is applied.
- Choose a long, unique password and store it safely.

PDF password protection - strong AES-256 encryption in your browser

With this tool you can set a PDF open password and apply content encryption. Processing is fully client-side, so the document is never uploaded. Printing, modification and content extraction restrictions are applied for compatible viewers.

How to use?

Select PDF: click to upload or drag and drop the file.
Enter password: type a strong password (12+ characters with uppercase, lowercase, numbers and symbols).
Encrypt: click Encrypt & save. The output is a new PDF that requires a password to open.
Download: save the file; its name ends with .secured.pdf.

Typical uses

Contracts and NDAs - protect them before sharing.
Invoices and financial reports - secure them before emailing.
HR and medical documents - protect sensitive data.
Project documentation (proposals, specifications) - for secure transmission.
Legal documents - prevent unauthorized access.

Frequently asked questions

What happens during encryption?: The entire document content is encrypted using the AES-256 algorithm; without the password the file cannot be opened.
Does the system set printing/modification restrictions?: Yes. In addition to the open password, printing and modification restrictions are set. Enforcement depends on the PDF reader.
What if I forget the password?: It cannot be recovered. Store it safely; if lost, the content cannot be restored.
Can I encrypt a password protected PDF?: No. Remove the existing protection first, then run the encryption.
How long should the password be?: We recommend at least 12-16 characters with a random combination. Avoid dictionary words and reused passwords.

Related tools: PDF merge, PDF compression, OCR - searchable PDF.

Password-protect PDFs before they leave your device

Password protection is most useful at the moment before sharing. If a PDF contains invoices, HR data, legal drafts, private school records or customer details, adding encryption before email or cloud upload reduces the damage from accidental forwarding or storage in the wrong place.

The password matters as much as the encryption option. Use a long phrase that is not reused elsewhere, and send it through a different channel than the PDF. For example, send the PDF by email and the password by phone or a separate message. Keep a secure record of the password, because strong encryption also means the file may not be recoverable if the password is lost.

Before protecting a PDF

Check that the final document is complete before encryption.
Use a unique password for each sensitive package.
Tell the recipient which app or viewer they should use if they have trouble opening the file.
Keep an unencrypted original in a secure local location if your workflow requires it.

This page focuses on creating a protected outgoing copy. It is not a password recovery tool, and it should not be used to bypass access controls on files you are not allowed to open.

A safer PDF workflow in three minutes

Before using any PDF tool, make a working copy and leave the original untouched. This gives you a clean fallback if a page is removed, a mark is misplaced, or an export setting produces a result you do not want. For sensitive documents, also check whether every page belongs in the file before you begin. Removing unrelated pages early is one of the simplest privacy improvements.

After export, open the output as a recipient would. Check page order, page orientation, small print, signatures, stamps, form fields and file size. If the PDF will be emailed, uploaded to a portal or stored in a shared folder, decide whether it should be compressed or password-protected first. The final copy should be the exact file you intend to share, not a draft that still needs explanation.

Use this quick checklist

Work on a copy, not the only original.
Remove pages and images that the recipient does not need.
Use a clear filename with purpose and date.
Open the exported PDF before sharing it.
Password-protect sensitive outgoing files and send the password separately.