n $9\mathrm{.}6$ Eavesdropping and Server Database Reading we asserted that it is extremely

difficult, without public key cryptography, to have an authentication scheme which

protects against both eavesdropping and server database disclosure. Consider the

following authentication protocol $($which is based on Novell version $3$ security$).$ Alice

knows a password. Bob, a server that will authenticate Alice, stores a hash of Alice's

password. Alice types her password $($say fiddlesticks$)$ to her workstation. The following

exchange takes place:

Is this an example of an authentication scheme that isn't based on public key

cryptography and yet guards against both eavesdropping and server database disclosure?

$($Hint: the purpose of the $7$th message is to prove to Bob that he is talking to Alice, but he

already knows that. Why?$)$