Create a key pair and export the public key
gpg --gen-key # To create your key
gpg --export <your_id> > hazel-public.asc # To export your key to a file
Import someone else's public key. Sign and encrypt a file for them.
gpg --import mkim-gpg-pubkey # To import my key
gpg -s -e -r "M Kim" <file_to_encrypt> # To sign and encrypt a file
Decrypt a file that was encrypted for you
gpg -d <file_to_decrypt> # To decrypt a file that was encrypted for any of your private keys