Importing keys into the apt keyring
Simple approach to loading apt keys from a key server into the apt keyring:
# import key to keyring from key server
sudo gpg –keyserver subkeys.pgp.net –recv-key A040830F7FAC5991
# check key fingerprint (optional)
sudo gpg –fingerprint A040830F7FAC5991
# export key to apt keyring
sudo gpg –armor –export A040830F7FAC5991 | sudo apt-key add -
This should address the following apt-get / aptitude error:
GPG error: http://dl.google.com stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A040830F7FAC5991