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Encrypt PDF

Encrypt PDF with AES-128 or AES-256 encryption

How to Use Encrypt PDF

  1. Upload the PDF you want to protect.
  2. Set an open password — this is required to view the document.
  3. Optionally set a separate owner password to control permissions.
  4. Tick the permissions you want to allow: printing, editing, copying, annotating.
  5. Encrypt and download the protected file.

About Encrypt PDF

What this page solves

Encrypt PDF solves the privacy and friction problem of typical online tools — it never uploads, never asks for a signup, and runs in your browser.

Encrypt PDF is a free, privacy-first PDF utility that lets you encrypt pdf with aes-128 or aes-256 encryption entirely in your browser. Unlike most online PDF services, Encrypt PDF never uploads your documents — every page is parsed, modified, and re-saved locally using pdf-lib and the browser's built-in capabilities. That makes it a safe choice for confidential files such as contracts, invoices, medical records, tax forms, or signed agreements that should never touch a third-party server. Because the processing is local, Encrypt PDF is usable on locked-down corporate laptops and school networks where uploading work files to a third-party service is a policy violation. Nothing you load into Encrypt PDF is uploaded: the file or text is read with the browser's own FileReader and processed in page memory, so the work finishes even if your connection drops mid-task. Encrypt PDF loads as a small bundle and is interactive within a second on mid-range phones, so it is practical to use it from a phone while away from a desk. Encrypt PDF follows a clean four-step workflow (Upload → Edit → Process → Download) inspired by the best desktop PDF apps and is part of our broader PDF Tools collection. If you also need a complementary utility, try our PDF Merger. It is free with no signup, no watermark, and no page count limits beyond what your device can handle.

Common Use Cases

  • Process confidential business documents without uploading them
  • Prepare contracts, invoices, or signed agreements before sharing
  • Edit scanned documents and forms locally on your device
  • Combine PDF tools in a chain — output of one becomes the input of the next
  • Handle large or sensitive PDFs that exceed typical online upload limits
  • Processing work files that company policy forbids uploading to external services
  • Reducing a thesis or dissertation PDF to fit a university submission size cap
  • Preparing tender or RFP responses where multiple PDFs need to merge into one bundle

Related tools in PDF Tools

See all PDF Tools.

Frequently asked questions

How strong is this encryption?

RC4 128-bit is the PDF 1.4 standard. It stops casual access and is supported by every PDF reader, but it is cryptographically dated. AES-256, which Acrobat uses, is substantially stronger. For material where a determined attacker is a realistic concern, use dedicated file encryption instead.

What is the difference between the two passwords?

The open password is needed to view the document at all. The owner password controls whether permissions can be changed. If you set only an open password, anyone who can open the file can also alter its permissions.

Can permissions actually stop someone copying text?

Not reliably. Permission flags are instructions that compliant readers choose to honour. Software that ignores them exists. Treat permissions as a clear statement of intent rather than enforcement.

I forgot my password. Can you recover it?

No. Nothing is stored anywhere — the encryption happens entirely in your browser and no record of the password exists. If you have lost it and no unencrypted original, the file is unrecoverable.

How to use Encrypt PDF?

1) Open the tool. 2) Enter or upload your input. 3) Get your result instantly. Everything happens locally — nothing is uploaded.

When should I use Encrypt PDF?

Use Encrypt PDF whenever you need a fast, private, browser-based way to encrypt pdf with aes-128 or aes-256 encryption.

Is Encrypt PDF safe?

Yes. Encrypt PDF runs 100% in your browser. Inputs are never uploaded, stored, or logged — safe for confidential content.

Will quality be affected by Encrypt PDF?

No quality loss for text and vector content. Embedded images keep their original resolution unless you compress them.

What formats does Encrypt PDF support?

Encrypt PDF supports PDF (any version), with import/export to JPG, PNG and TXT in related tools

Is Encrypt PDF free?

Yes — Encrypt PDF is completely free, with no registration, no watermarks, and no usage limits.

Is my PDF uploaded to a server?

No. Encrypt PDF processes PDFs entirely in your browser using pdf-lib. Your documents never leave your device.

Are there file-size or page limits?

There are no enforced limits. Performance depends on your device — files up to about 100 MB process smoothly on most modern browsers.

Will the output have a watermark?

Never. Encrypt PDF produces clean PDFs with no added branding, watermarks, or metadata.

Is Encrypt PDF safe for confidential documents like contracts and medical records?

Yes. Encrypt PDF processes PDFs entirely in your browser using pdf-lib. The document never leaves your device — no upload, no server-side temp file, no audit-log entry. You can verify in DevTools → Network: zero outbound traffic after the page loads.