$1)$ You are tasked with designing a hash function HHH that utilizes bitwise XOR operation. Calculate the hash value of the concatenated string "Hello" $+$ "World" using HHH$.$

$2)$ Encrypt the message "SECRET MESSAGE" using a $4$x$4$ ROUTE cipher with the keyword "ENIGMA

$3)$ Consider a $3$x$2$ Hill Cipher matrix A $=[[2,1,5],[7,4,3],[1,0,2]].$ Encrypt the plaintext "ATTACK" using matrix multiplication.