Question $4$

A plaintext was encrypted using Caeser cipher and the ciphertext obtain is

gfrgh Fdhvdu

If the letter $g$ decodes to $d,$ what is the plaintext?

decode Caesar

dcode Caesar

dcode Ceasar

ecode Ceasar

Question $5$

The ASCII code for letter T is $01010100(54$ in hexadecimal$)$ and for letter O is $01001111(4$F in

hexadecimal$).$

Hence, the word TO is represented as $0101010001001111(544F$ in hexadecimal$)$ in your computer.

You choose a key that is not random for One Time Pad, say you choose the key so that all positions

have the same bits: $1111111111111111.$ Then the ciphertext is computed by performing the

bitwise XOR operation: $0101010001001111o+1111111111111111$

$1010101110110000$

$0010101110110000$

$1010101100110000$

$1010101110110001$