The remote host computer is willing to accept your public key to authenticate you in the future.
Type in the passphrase associated with this key. You defined the passphrase when you created the public key. See Section Key Generation - Enter Passphrase for more information.
If password authentication is listed after public key on the Authentication page of Profile Settings, when you press the Enter key, public-key authentication is not used, and the system will ask you to type in your password instead.