CODES AND CIPHERS.

Bifid Cipher

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