Adding or changing a passphrase for an existing private key

You can change the passphrase for an existing private key without regenerating the keypair by typing the following command:

$ ssh-keygen -p -f ~/.ssh/id_rsa

> Enter old passphrase: [Type old passphrase]

> Key has comment 'your_email@sqley.com'

> Enter new passphrase (empty for no passphrase): [Type new passphrase]

> Enter same passphrase again: [Repeat the new passphrase]

> Your identification has been saved with the new passphrase.

If your key already has a passphrase, you will be prompted to enter it before you can change to a new passphrase.