Is the password sent anywhere?

No. Encryption happens in your browser and the password is used only there. If you forget it, we cannot recover it — nobody can.

How strong is the protection?

The file is encrypted with AES-256; the weak point is the password itself. Use at least 12 characters with a mix of words or symbols.

What do the permission restrictions do?

They ask viewers to disable printing, copying or editing. Compliant viewers respect them; a determined user can bypass permissions, so rely on the open password for confidentiality.

PDF Tools

Protect PDF

Name: Protect PDF
Author: Miikka

Encrypt a PDF so it can only be opened with a password. Optionally block printing, copying and editing. The password never leaves your device.

By Miikka · CalcBrew · Updated Sep 24, 2026

Runs in your browser — files never leave your device.

Drop PDF file here

or click to browse · paste from clipboard · up to 100 MB

Select file

Options

Password to open

Prevent printingPrevent copying textPrevent editing

About Protect PDF

Emailing payslips, medical records or contracts unencrypted means anyone who intercepts or forwards the message can read them. A PDF password encrypts the content itself, so the file is protected wherever it ends up.

AES-256, the encryption used here, is the current PDF standard (PDF 2.0) and is supported by Acrobat, Preview, Chrome, Edge and every mainstream viewer.

How to protect PDF

Drop PDF file onto the box above, click it to browse, or paste from the clipboard.
Adjust the options if you need to — the defaults suit most cases.
Press Convert. The work happens on your device, so speed depends on your computer or phone.
Download the result.

About the format

PDF · Portable Document Format · .pdf

The fixed-layout document standard: looks the same on every device and printer, which is why forms, invoices, contracts and reports are shared as PDF.

A PDF can contain vector text, embedded fonts, images, form fields, annotations and digital signatures.
Scanned PDFs are just pictures of pages; they need OCR before the text can be searched or copied.
PDF is an open ISO standard (ISO 32000) since 2008.

Related conversions

Unlock PDFOn-deviceRemove a password from a PDF you can open.Flatten PDFOn-deviceLock filled forms and annotations into the page.Sign PDFPopularOn-deviceDraw or type a signature and place it on the page.Merge PDFPopularOn-deviceCombine several PDFs into one, in the order you choose.Split PDFPopularOn-deviceCut a PDF into separate pages or page ranges.Rotate PDFOn-deviceTurn pages the right way up and save the PDF.

Frequently asked questions

Cite this calculator

APACalcBrew. (2026). Protect PDF. https://calcbrew.com/protect-pdf

MLA“Protect PDF.” CalcBrew, 2026, calcbrew.com/protect-pdf.

Link to https://calcbrew.com/protect-pdf. Results are estimates; cite the underlying formula or data source for academic work.