What PDF encryption does Preview use on macOS Catalina?

Does anyone know what type of encryption does macOS Catalina uses for encrypting PDF files using the Preview app? Thanks a lot.

Posted on Apr 15, 2020 11:10 AM

Similar questions

PDF Encryption I am trying to find out how securely Preview encrypts PDF files. For example, does Preview use 128 or 256 bit encryption? How long can the PDF file password be? How secure are PDF files when encrypted with Preview? All the info I’ve found is 3+ years old, so looking for something more recent. Thx.
631 1
Encryption of pdf in preview I tried to password-protect a pdf file using the preview in Mac Air. However, after saving the file while I try to reopen it, the file is reopening without a password prompt. How to fix it?
1123 1
preview encrypt not working Open PDF in Preview -- Big Sur 11.4 Preview Export... Click Encrypt option. Un-click any other option. Enter PW Save ------------- Finder Info indicates file is Encrypted. Opening the file (even after restarted computer) opens without asking for a PW. Copying file to USB drive, and opening on another Mac, also opens into Preview without asking for a PW. I have tried many times, including duplicating the file first, and then saving using encrypt option. It seems to be a bug, because I have done this previously (in older MacOS versions using Preview). Any suggestions? I see 11.6 is available, so will upgrade to that and try again.
1593 3

1 reply

VikingOSX

Level 10

130,378 points

Apr 15, 2020 11:28 AM in response to michaelmndoza

128-bit AES. Want more, then choose a PDF Editor that can provide 256-bit, though at the expense of compatibility with PDF readers that may not support that level of encryption.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

What PDF encryption does Preview use on macOS Catalina?

Welcome to Apple Support Community

A forum where Apple customers help each other with their products. Get started with your Apple Account.

Learn more Sign up