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PDF · Protect

Protect your PDF. AES-256, no upload.

Add AES-256 encryption to any PDF in seconds. Set open and owner passwords separately, restrict printing, copying and editing — all in your browser.

  • AES-256 encryption stored in the PDF — compatible with every reader.
  • Set separate open password and owner password independently.
  • Granular permissions: restrict printing, copying, editing, and annotations.
Encryption →
AES-256 Owner pw User pw Permissions
→ Encrypted PDF

Trusted by 390K people · 720K PDFs protected every month

Your PDFs stay in the browser throughout. No upload, no account.

390K
Monthly users
720K
Protected / month
0
Files uploaded
What people say

From legal teams to freelancers — they protect here.

★★★★★

I send client proofs weekly. Password-protect before emailing, nothing uploaded anywhere.

LM
Laura M.
★★★★★

Setting separate open and owner passwords for our contract templates is exactly what we needed. No software to install, no cloud upload.

DK
David K.
★★★★★

We protect salary letters with a unique password per employee. AES-256 and nothing ever hits a server. Compliance approved this immediately.

PS
Priya S.
★★★★★

Restricting copying and printing on NDAs used to require Acrobat Pro. This does it for free in under a minute. Incredible for a browser tool.

MB
Max B.
★★★★★

I protect exam papers before sharing with students. The browser-only approach means I never worry about a cloud provider seeing the questions.

WL
Dr. Wei L.
★★★★★

Our GDPR assessments are sensitive. AES-256 encryption without anything touching a server is exactly what the team needed.

HR
Helen R.
★★★★★

Financial reports go out with copy restrictions every quarter. Replaced the desktop tool we used — nothing to install, runs anywhere.

GT
Gil T.
★★★★★

We handle dozens of protected PDFs each month. Setting the permission matrix locally, without any cloud service involved, is what got it through compliance review.

SV
Sophie V.
★★★★★

I send client proofs weekly. Password-protect before emailing, nothing uploaded anywhere.

LM
Laura M.
★★★★★

Setting separate open and owner passwords for our contract templates is exactly what we needed. No software to install, no cloud upload.

DK
David K.
★★★★★

We protect salary letters with a unique password per employee. AES-256 and nothing ever hits a server. Compliance approved this immediately.

PS
Priya S.
★★★★★

Restricting copying and printing on NDAs used to require Acrobat Pro. This does it for free in under a minute. Incredible for a browser tool.

MB
Max B.
★★★★★

I protect exam papers before sharing with students. The browser-only approach means I never worry about a cloud provider seeing the questions.

WL
Dr. Wei L.
★★★★★

Our GDPR assessments are sensitive. AES-256 encryption without anything touching a server is exactly what the team needed.

HR
Helen R.
★★★★★

Financial reports go out with copy restrictions every quarter. Replaced the desktop tool we used — nothing to install, runs anywhere.

GT
Gil T.
★★★★★

We handle dozens of protected PDFs each month. Setting the permission matrix locally, without any cloud service involved, is what got it through compliance review.

SV
Sophie V.
How it works

Protect in three steps

Upload, configure, download. Your PDF is encrypted entirely in your browser.

STEP 01

Drop your PDF

Drag your PDF onto the upload zone. The file never leaves your device — everything runs locally in WebAssembly.

STEP 02

Set password & permissions

Enter your open password, set an owner password, and toggle which actions to allow or block in the document.

Open pw
Owner pw
Allow printing
Allow copying
Allow editing
STEP 03

Download protected PDF

Click Protect. Your browser encrypts the file with AES-256 and triggers the download instantly.

secured.pdfAES-256 · locked
Allow printing
Allow copying
Allow editing
Allow annotations
Permissions

Control exactly what recipients can do

Beyond the open password, set an owner password that governs the permission layer. Independently allow or block printing, text copying, editing, and annotations.

  • 01
    Open vs owner passwordThe open password lets readers view the document. The owner password controls permissions — they can be set independently.
  • 02
    Per-action controlDecide independently whether to allow printing, copying text, editing content, and adding comments or annotations.
  • 03
    PDF-standard compatiblePermissions are embedded in the PDF spec itself — respected by Adobe Acrobat, Preview, Chrome, and every compliant reader.
Encryption strength
AES-256-CBC
PDF 1.7 · Maximum encryption
Encryption

AES-256: the strongest PDF encryption available

The same cipher used by governments and banks. AES-256-CBC in PDF 1.7 mode is the highest encryption level defined by the PDF specification — unbroken by any brute-force attack.

  • 01
    256-bit key space2²⁵⁶ possible keys. All the computers on Earth combined cannot brute-force AES-256 before the heat death of the universe.
  • 02
    PDF 1.7 spec compliantThe output is a standard encrypted PDF — no proprietary format, no extra plugin needed to open it on any device.
  • 03
    Password never transmittedEncryption runs in WebAssembly inside your browser. Your password is never sent anywhere — not even to us.
FAQ

Common questions

What encryption standard does kindatool use?
We use AES-256-CBC, the highest encryption level defined in the PDF 1.7 specification. It is the same standard used in government, banking, and enterprise security and is considered unbreakable by brute force with current technology.
Is my password stored on your servers?
No. The entire encryption process runs inside your browser using WebAssembly. Your password and your PDF never leave your device — there are no servers receiving this data. You can verify this by watching the Network tab in DevTools during protection.
Can I set different passwords for opening and for permissions?
Yes. The PDF spec supports two distinct passwords: the user (open) password which lets anyone view the document, and the owner password which controls permissions like printing and copying. You can set either or both independently.
Will the protected PDF work in all PDF readers?
Yes. The output is a standard PDF 1.7 encrypted file. It opens correctly in Adobe Acrobat, macOS Preview, Google Chrome's built-in viewer, Foxit, and any other compliant PDF reader. Recipients simply enter the password when prompted.
Does protecting a PDF change its appearance or file size?
No visual content is changed. The file size may increase slightly due to encryption overhead — typically less than 1%. Text, images, fonts, and layout remain identical. The only difference is that the content is now encrypted inside the file.
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Ready to protect your PDF?

No account. No upload. No watermark. AES-256 encryption runs entirely in your browser — your password stays yours.

AES-256100% localNo accountFree forever