gpg

# search a gpg public key
gpg --search-keys <email/id/etc>

# download a public key
gpg --recv-keys <id>

# specify key server
gpg --keyserver <server> --recv-keys <id>
gpg --keyserver hkps://keys.openpgp.org --recv-keys 288DD1632F6E8951

More Info:

• gpg2
• gpg documentation
• how-to-use-gpg-to-encrypt-and-sign-messages