The best way to backup your identity is by selecting guardians under the backup identity option under your profile menu. This uses threshold cryptography implemented in Sharmir's Secret Sharing System. It requires that you have at least two trusted peers that know you personally and can verify you in the event of your identity loss and recovery process.

Kudos is derived from your identity - there is no separate key to be backed up. As long as your identity is backup up your kudos is also then backed up.