$(1$ point$)$ This question concerns block cipher modes. We will use a simple affine

cipher, which can be expressed in $C$ as follows.

Note that the block size is $8$ bits, which is one byte $($and one ASCII character$).$ We will

work with the fixed key $0x08.$

We now encrypt various plaintexts using modes for this cipher. In every case in which

the mode requires an IV$,$ the IV will be OxAA. In the case of CTR mode, we use a

$($nonce $||$ counter$)$ arrangement in which the nonce is the left $5$ bits of $0$xAA and the

counter is a $3$ bit counter that begins at $0.$ In all of the problems given below, one

character is one block. Each character of the plaintext should be regarded as its

corresponding ASCII code.

a$)$ Encrypt the plaintext "happy" using $CTR$ mode. Please enter your answer in hex.

$($Please do $**$ not ${?}^{****}$ enter an $0x,$ as this has been done.$)$

$0x$

b$)$ Encrypt the plaintext "frogs" using ECB mode. Please enter your answer in hex.

$0x$

c$)$ Encrypt the plaintext "sitting" using $CFB$ mode. Please enter your answer in hex.

$0x$

d$)$ Encrypt the plaintext "crisscross" using $CBC$ mode. Please enter your answer in

hex.

$0x$

e$)$ Encrypt the plaintext "style" using OFB mode. Please enter your answer in hex.

$0x$