Type: Substitution
CIPHER: First column and firs row contains numbers while the rest is letters)
⭐A B C D E
A|A|B|C|D|E
B|F|G|H|J|K
C|L|M|N|O|P
D|Q|R|S|T|U
E|V|W|X|Y|Z
Ciphertext: CB CD CC BD AA ED
Plaintext: M O N D A Y
