$.$substitution table:The affine encryption protocol is given below. According to this, encode and decipher the word "HELLO" for $=15,=10.$ Input$/$output: $\{$a$,$b$,....,$z$\}$ with encoding $\{0,1,.....,25\}$ Encryption: E$($x$)=$ a x $+($mod $26)$ such thad gcd$($a$,26)0123456789$MNOP$1213141516$TUVWZ$2425101117181922232021$Answer: Decryption: D$($y$)=$ Y y $+($mod $26)$ such that Y $=$ a$($mod $26)$ and $=-$ a$($mod $26)$