PGP and GPG PGP - Pretty Good Privacy GPG - GNU Privacy Guard oder GnuPG https://en.wikipedia.org/wiki/Pretty_Good_Privacy
The Free Software Foundation has developed its own OpenPGP-compliant program called GNU Privacy Guard (abbreviated GnuPG or GPG).
Install GPG on MacOS Installing homebrew first
Refer to https://blog.ghostinthemachines.com/2015/03/01/how-to-use-gpg-command-line/
And install it.
brew install gnupg Use GPG keygen Generate a key pair
gpg --gen-key Real name: My Realname Email Address: firstname.lastname@example.org (Okay) (Enter the pass) As a default, the key type is RSA 2048.