brew install gpg2
sudo ln -s /usr/local/bin/gpg2 /usr/local/bin/gpg
gpg --import salt-masterless_pubkey.gpg
# import pub key into keyring
gpg --import salt-masterless_pubkey.gpg
# encrypt message using pubkey
echo -n "supersecret" | gpg --armor --batch --trust-model always --encrypt -r salt-masterless