This object selects the signature method -- combining an algorithm (Diffie-Hellman anonymous, DSA, or RSA) with a hash function (SHA or MD5) -- used to authenticate the key exchange during TLS handshakes. An admin moves this away from the insecure default of dhAnon(1), which provides no authentication at all, to an authenticated option like rsaSha1(4) to protect against man-in-the-middle attacks on the management session. For example, setting this to rsaSha1(4) has the device authenticate key exchanges using RSA signatures over a SHA-1 hash instead of no signature at all.