Encrypt PDF on Linux, decrypt on Mac? (in 2023)

Question

There are many tools available for the Linux user to encrypt a file: Encrypting/Decrypting a single file in Ubuntu 12.04 LTS.

I want to…

1. encrypt a single PDF on my Linux OS,
2. email it to a non-technical user on a Mac and
3. expect they can easily decrypt the PDF(using a password I provide through "another channel".

Ideally, the non-technical recipient is not required to install additional software. Preferred (fool-proof) solutions involve native-to-macOS (built-in) capabilities or, perhaps, double-clicking a password-protected "self-extracting" file ... minimal experience or thinking needed.

My knowledge of macOS is thin. Suggestions?

( Side question - first post from a no-longer-virgin Stack Exchange user.
Should this have instead gone to https://unix.stackexchange.com/ ?)

Answer 1

Recommendations for software (and Linux software at that) are off-topic, but: password-protected encryption is part of the PDF standard, so any Linux PDF-compliant app should be able to create a PDF that requires a password to open it.

On MacOS, Apple's built-in Preview app can open encrypted PDFs, if the password is entered.

For other file formats, zip encryption with a password may be a good option.

Answer 2

The PDF standard (2.0) uses AES 256-bit encryption.^*

This is platform agnostic meaning if it is a PDF file, then it can be encrypted/decrypted on any OS on any processor including Apple Silicon and ARM. In your example, you can encrypt using Ubuntu (or Mint or Kali or whatever), then decrypt it on Mac and even Windows. Vice versa, a PDF encrypted on a Mac (or Windows) can be decrypted on Linux. The native PDF tools on each OS will work fine.

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^* Wikipedia link provided. Official ISO 32000-2-2020 Standard Definition is behind a paywall. Click the link and search for “encryption”.