GPGTools

GPGTools is a macOS-focused software suite that provides OpenPGP-based encryption tools, including an Apple Mail plugin (GPG Mail), a key manager (GPG Keychain), and integration services (GPG Services). The tools are built on the GNU Privacy Guard (GnuPG) project and are provided as a bundled package (GPG Suite) for users seeking easier encryption workflows on macOS. The project has been associated with GPGTools GmbH as its developer in some sources, while other references describe it as a community/open-source project built around GnuPG. (gpgtools.com)