Password-protect a PDF — real AES-128 encryption
Add an opening password to a PDF and download a protected copy. Save the password first, and check that the new file opens before sending it.
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Check the protected copy. The tool reportsAES-128 encryption. Reopen the downloaded file to check that it asks for your password. The strength meter is a rough estimate and can overrate predictable words or patterns.
Print and copy limits are only requests. PDF readers can ignore them. Someone who can open the file may still copy or print its contents.
Use a long, unique password and save it somewhere you can retrieve it. The form clears it after export, and ToolsNow cannot reset it for you. Keep the original until you have checked the protected copy.
How to use
- Choose an unprotected PDF. Keep the original somewhere appropriate. This form cannot change the password on an already encrypted file.
- Set and save a password. Fill Password and Confirm password, or use Suggest a strong password. Save it in your password manager before continuing.
- Review the permission requests. Ask readers not to print and Ask readers not to copy text are advisory settings, not a way to stop a recipient sharing the contents.
- Protect PDF. The fields clear after a successful export. Open the saved file with the password and check it before sharing the file and password separately.
Questions
Does every file use AES-128?
The panel says AES-128, but the current library chooses encryption from the source PDF version. PDF 1.6/1.7 uses AES-128; older versions can use weaker RC4 encryption. There is no algorithm selector here. If a particular encryption standard is required, use a PDF editor that lets you select and verify it.
What if I lose the password?
ToolsNow has no password lookup or reset. You may need your saved password, an unprotected original or another copy from the sender. Recovery software can sometimes guess a weak password, but you should not rely on being able to recover a lost one.
Can I trust the strength label for a password I type?
Treat it as a rough length-and-character check. It does not recognise predictable phrases, reused passwords or personal information. A long random suggestion saved in a password manager is a better choice than making a familiar word look complicated.
Does it upload or securely erase my password?
Encryption is performed in the browser and the tool does not send the password to a processing server. It clears the form after success, but that is not secure erasure from browser or device memory. Site resources still load over the network, and any password you copy may remain in clipboard history.
What happens to text and forms?
Protection does not deliberately turn the pages into pictures, but complex forms, signatures and reader compatibility need checking in the saved file. Avoid using the unlock tool here as a preparation step if you need those features: its output is image-based.
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