consider a 4-bit block cipher, described in hexadecimal by the table below.

a) Use CTR mode to encrypt the message "face" using the above in CTR, with a one-bit nonce of 1 and three bits of a coutner that starts with 0.

b) Decrypt the message "46e2" using the above cipher in CTR mode, with a one bit nonce of 1 and three bits of a counter that starts with 0.

c) was this easier or harder than using CBC mode? Do you suspect any difference in security?

Plaintext	Ciphertext	Plaintext	Ciphertext
0	a	8	e
1	c	9	d
2	f	a	0
3	6	b	7
4	3	c	5
5	8	d	b
6	4	e	9
7	2	f	1