gpg
How to edit a
gpg --edit-key 97DFS8D7FS8DF79S8DF
Change how the primary key can be used
gpg> change-usage
Changing usage of the primary key.
Possible actions for a RSA key: Sign Certify Encrypt Authenticate
Current allowed actions: Sign Certify
(S) Toggle the sign capability
(E) Toggle the encrypt capability
(A) Toggle the authenticate capability
(Q) Finished
Update the expiry date
gpg > expire