Set an opening password and create an AES-256 encrypted PDF.
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How to use Lock PDF
- Open the PDF with any existing opening password.
- Set a new opening password and retain it safely.
- Submit, download the encrypted copy and reopen it to check the password.
Frequently Asked Questions
What if I forget my password?
Keep your password safely. We do not retain a recoverable password or provide password recovery.
Will opening the locked PDF require a password?
Yes. It uses an opening password and AES-256 encryption. Test the downloaded file in a compatible reader rather than relying on the preview alone.
Can I only prohibit printing or copying without an opening password?
The interface provides opening-password encryption, not independent permission-password settings or DRM management. Reader permission flags are not absolute usage control.
Can I change an existing opening password?
Provide the current password first, then set a new one and save a new encrypted copy. The original file on disk stays unchanged.
Why can’t an old reader open the locked file?
Older readers may not support AES-256 or the encryption version. Update the reader and verify the password before assuming corruption.