Answer: Secret Code #81

The secret message says:

SING

The shift was 9.

The secret note decoded: SING
The note, decoded.

Letter by letter

Secret letterBPRW
Real letterSGIN

Decode it with Python

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

secret = "BRWP"
shift = 9
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:

SING

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.