Mailvelope is a browser add-on that helps use GPG encryption and signing on webmail systems like Gmail. Here are the steps on macOS (tested with "Big Sur") to get Mailvelope to use the GnuPG backend. Install gpgme via Homebrew: brew install gpgme This will install gpgme-json in /usr/local/bin by default. Create a file called gpgmejson.json in "~/Library/Application Support/Google/Chrome/NativeMessagingHosts" with the following contents: { "name": "gpgmejson", "description": "Integration with GnuPG", "path": "/usr/local/bin/gpgme-json", "type": "stdio", "allowed_origins": [ "chrome-extension://kajibbejlbohfaggdiogboambcijhkke/" ] } Now in Mailvelope > Options > General , GnuPG will show up as the encryption backend.
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