S server introduces a new challenge response authentication option. This challenge response is based on a wrapper we call NKeys which uses <a href="https://ed25519.cr.yp.to/" target="_blank">Ed25519</a> signing. The server can use these keys in several ways for authentication. The simplest is for the server to be configured with a list of known public keys and for the clients to respond to the challenge by signing it with its private key. This challenge-response ensures security by ensuring that the client 