PDF tools · Free browser tool

Protect or Unlock a PDF

Add AES-256 password protection to a PDF or remove protection using a password you already know, entirely on this device.

Phone and computer friendly No document upload Free to use

Private workspace

Control PDF password protection locally without disclosing the document or password to a server.

Local processing

Tab memory only New output file Review before sharing

Your file is processed by code already loaded in this tab. Your device, browser, extensions, downloads, and any later sharing remain part of the trust boundary.

Ready. Choose a file to begin.

Choose a PDFPDF · Up to 50 MiB · You must know any existing passwordChoose PDF

Operation Protect with AES-256 Remove a known password Change a known password

New passwordUse a unique password and store it safely. NullKit cannot recover it.

Confirm new password

Reader permissions Allow full-quality printing Allow text and image extraction Allow document modification

Permissions depend on PDF-reader cooperation. The password encryption is the meaningful control.

Choose a file to begin

Control PDF password protection locally without disclosing the document or password to a server.

What this tool does

A focused PDF job, with a visible boundary.

Control PDF password protection locally without disclosing the document or password to a server.

AES-256 protection

Known-password unlocking

Local permission controls

Know the limits

Local does not mean unlimited.

Browser processing avoids an upload workflow, but available memory, PDF structure, digital signatures, and the settings you select still matter.

This tool does not crack, guess, or recover unknown passwords.
PDF permission flags depend on reader cooperation and are not a substitute for encryption.
Losing the password can make the protected copy inaccessible.

Four local steps

How to use pdf password tool.

01
Choose a PDF and select protect or unlock mode.
02
For protection, create and safely store a strong password; for unlocking, enter the current password.
03
Process the document locally.
04
Verify the output and remove temporary password copies.

Clear answers

PDF password tool questions.

Can this recover a forgotten password?

No. Unlocking requires the correct user or owner password and does not attempt guessing or circumvention.

Which encryption is used?

New protected copies use AES-256 by default.

Does NullKit see the password?

No. It remains in the current page and is used only by the local PDF engine.

Protect or Unlock a PDF

Control PDF password protection locally without disclosing the document or password to a server.

Digital signature detected

Choose a file to begin

Result ready

A focused PDF job, with a visible boundary.

AES-256 protection

Known-password unlocking

Local permission controls

Local does not mean unlimited.

How to use pdf password tool.

Choose a PDF and select protect or unlock mode.

For protection, create and safely store a strong password; for unlocking, enter the current password.

Process the document locally.

Verify the output and remove temporary password copies.

PDF password tool questions.

Protect or Unlock a PDF

Digital signature detected

Choose a file to begin

Result ready

A focused PDF job, with a visible boundary.

AES-256 protection

Known-password unlocking

Local permission controls

Local does not mean unlimited.

How to use pdf password tool.

Choose a PDF and select protect or unlock mode.

For protection, create and safely store a strong password; for unlocking, enter the current password.

Process the document locally.

Verify the output and remove temporary password copies.

PDF password tool questions.

More private PDF tools.