Alice is learning about the Vigen$$re cipher. She chooses a random six$-$letter word $($so all six$-$letter words in the dictionary have the same probability$)$ and encrypts it using a Vigen$$re cipher with a randomly chosen key of length $3($that is$,$ each possible key has probability

$1$

$/$

$26$

$3$

$).$ Eve intercepts the ciphertext eblkfg.

Compute the conditional probability

$$

$($

$$

$=$

$$

$$

$$

$$

$$

$$

$$

$$

$=$

$$

$$

$$

$$

$$

$$

$)$

$.$

Use your result from part $($a$)$ to show that the Vigen$$re cipher does not have perfect secrecy$.$