a) Assume a message m is encrypted using the Shift cipher and the resulting ciphertextis as follows?JBCRCLQRWCRVNBJENBWRWNWhat would be the values of m and key k in this case? Please justify your answer.(Hint: you need to do an exhaustive search over 26 possible keys

b) When using the one-time pad with the key k = 0`, we have Enck(m) =k ⊕ m = m and the message is sent in the clear! It has therefore beensuggested to modify the one-time pad by only encrypting with k 6= 0`(i.e., to have Gen choose k uniformly from the set of nonzero keys oflength `). Is this modified scheme still perfectly secret? Explain.