$16\mathrm{.}1+16\mathrm{.}2$ In Section $16\mathrm{.}4,$ we outlined the public$-$key scheme proposed in $[$WOO$92$a$]$ for the distribution of secret keys. The revised version includes IDA in steps $5$ and $6.$ What attack, specifically, is countered by this revision?The protocol referred to in Problem $16\mathrm{.}1$ can be reduced from seven steps to five, having the following sequence: a$.$ A S B: b$.$ A S KDC: c$.$ KDC S B: d$.$ B S A: e$.$ A S B: Show the message transmitted at each step. Hint: The final message in this protocol is the same as the final message in the original protocol.