Problem $1$: $($based on book $10\mathrm{.}14)$

$[30$ pts$]$ In Kerberos, Alice's key $K_4,$ which is shared by Alice and the KDC$,$ is computed on Alice's computer as password$).$ Alternatively, this could have been implemented as follows:

Initially, the key $K_n$ is randomly generated on Alice's computer. The key is stored on Alice's computer as $E(K_n,K)$ where the key $K$ is computed as password$).$ The key $K_n$ is also stored on the KDC$.$

What are the advantages to this alternate approach of generating and storing $K?$

Are there any disadvantages to this approach?