GnuPG, GNU Privacy Guard, is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP). GnuPG allows you to encrypt and sign your data and communications.
# You will be prompted with a few questions. Follow the instructions to generate the key.
gpg --full-generate-key
List Keys
# List the private keys
gpg --list-secret-keys [--keyid-format=long]
# List the public keys
gpg --list-keys [--keyid-format=long]
Export Keys
# Export the private key
gpg --output /path/to/output/private.asc --armor --export-secret-key KEY_ID
# Export the public key
gpg --output /path/to/output/public.asc --armor --export KEY_ID
Import Key
gpg --import /path/to/key
Delete Keys
# Delete private keys
gpg --delete-secret-key KEY_ID [...KEY_IDS]
# Delete public keys
# - If the public key is associated with the private key, the private key has to be deleted first.
gpg --delete-key KEY_ID [...KEY_IDS]
Encryption/Decryption
# Encrypt the file
# - You must first import the public key of the recipient.
gpg --output /path/to/encrypted.txt.gpg --encrypt --recipient someone@example.com /path/to/plain.txt
# Decrypt the file
# - You will need the corresponding private key.
gpg --output /path/to/plain.txt --decrypt /path/to/encrypted.txt.gpg
Signature
# Sign the message
shasum -a 256 /path/to/file.txt | awk '{print $1}' > /path/to/file.txt.sha256sum
gpg --output /path/to/file.txt.sha256sum.sig --sign /path/to/file.txt.sha256sum
# Verify the signature
gpg --verify /path/to/file.txt.sha256sum.sig
