In each of the following schemes $E_k(m)=[m+k(mod3)].$ State in each case whether the scheme is

perfectly secret, and justify your answers.

A$.$ The message space is $=\{0,1\},$ and Gen chooses a uniform key from the key space $K=\{0,1\}.$

B$.$ the message space is $M=\{0,1,2\},$ and Gen chooses a uniform key from the key space $K=\{0,1,2\}.$

C$.$ The message space is $=\{0,1\},$ and Gen chooses a uniform key from the key space $K=\{0,1,2\}.$