GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP). GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications. GnuPG is Free Software (meaning that it respects your freedom). It can be freely used, modified and distributed under the terms of the GNU General Public License.
Generating keys
gpg --full-gen-key
Listing keys
gpg --list-keys
Exporting a public key
gpg --armor --export user@domain.org > publickey
Exporting a private key
gpg --armor --export-secret-keys user@domain.org > publickey
Importing a public key
gpg --import friend.gpg
gpg --edit-key friend@domain.org
fpr
sign
check
Import a public key on GPG site
gpg --keyserver gpg.mit.ed --send-key <key>
gpg --keyserver pgp.mit.edu --search <email>
gpg --keyserver pgp.mit.edu --sign-key <key>
Encrypting and decrypting documents
gpg --output doc.gpg --encrypt --recipient friend@domain.org doc
gpg --output doc --descript doc.gpg
gpg --output doc.gpg --symmetric doc
Tips
If you have problems with pinentry program, try (overwrite your correct path to pinentry program):
gpg-agent --daemon --use-standard-socket --pinentry-program /home/dani/.guix-profile/bin/pinentry-curses