Answer: Secret Code #9

The secret message says:

HIGH FIVE!

The shift was 5.

The secret note decoded: HIGH FIVE!
The note, decoded.

Letter by letter

Secret letterAJKLMN
Real letterVEFGHI

Decode it with Python

This program does the decoding for you. Change the secret and the shift to crack other messages!

secret = "MNLM KNAJ!"
shift = 5
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:

HIGH FIVE!

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.