$($a$)$ Shift Cipher with key $6.$

$($b$)$ Vigen$`$ere Cipher with blcok size m $=5$ and key K $=(13,7,43,28,50).$

$($c$)$ Product Cipher defined as E$($k$1,$k$2)$

$($m$)=$ E

$(1)$

k$1$

$($E

$(2)$

k$2$

$($m$)),$ where E

$(1)$

k$1$

is the Caesar Cipher

defined in Problem $1($a$)$ and E

$(2)$

k$2$

is the Vigen$`$ere Cipher as in $1($b$).$