加密 PDF

The user password is required and is what anyone must type to open the file. The owner password is optional; when you set a different one, the PDF also gets usage restrictions, so someone who opens it with only the user password can't print, copy, edit, annotate, fill forms, or rearrange pages.

256-bit AES, applied with QPDF's implementation of the PDF 2.0 encryption standard. There is no option to pick a weaker cipher, so the strength of the protection comes down to how strong your password is.

There is no recovery. AES-256 can't be brute-forced in any practical time, and BentoPDF keeps no copy of the file or the password. Store the password somewhere safe and keep an unprotected original for yourself.

No. With only a user password the file needs the password to open, but once opened there are no limits on printing, copying, or editing. Add a separate owner password if you want those restrictions.

Not with this tool, because the user password is mandatory here. Use Change Permissions instead, which applies restrictions while leaving the file openable without a password.

Open the protected file in the password removal tool, enter the password, and download a copy with the encryption removed. You need the password to do this; there is no bypass.

Any current PDF reader, including Adobe Reader, Preview, Chrome, Firefox, and Edge, opens AES-256 encrypted files. Very old readers released before AES-256 support was added may refuse the file.

No. QPDF runs as WebAssembly in your browser, so the file is encrypted on your device and neither the document nor the passwords are transmitted. Share the password with your recipient through a different channel than the file itself.