Four-square. Two plaintext squares (top-left and bottom-right) are the straight alphabet A–Z omitting J. I and J share.
Top-right ciphertext square — keyword RAIL, then the rest, I/J share, no J:
R A I L B
C D E F G
H K M N O
P Q S T U
V W X Y Z
Bottom-left ciphertext square — keyword SHIP, then the rest, I/J share, no J:
S H I P A
B C D E F
G K L M N
O Q R T U
V W X Y Z
Split the message into digraphs. First letter → row/col in top-left; second → row/col in bottom-right. Cipher letters are the other two corners: top-right, then bottom-left.
Ciphertext:
RI SP FR GI SD GM
Restore spaces for the answer.
The paper
Comments
No notes on this story yet.
Sign in to comment