The secret message says:
CUB
The shift was 4.
Letter by letter
| Secret letter | F | G | Y |
|---|---|---|---|
| Real letter | B | C | U |
Decode it with Python
This program does the decoding for you. Change the secret and the shift to crack other messages!
secret = "GYF"
shift = 4
message = ""
for letter in secret:
if letter.isalpha():
number = (ord(letter) - ord("A") - shift) % 26
message = message + chr(number + ord("A"))
else:
message = message + letter
print(message)When you run it, it prints:
CUB
Did you know? Shift codes are very old. A Roman writer called Suetonius said that Julius Caesar wrote secret letters by shifting the alphabet by three. That’s why it’s often called the Caesar cipher.