Answer: Secret Code #135

The secret message says:

WELL DONE!

The shift was 17.

The secret note decoded: WELL DONE!
The note, decoded.

Letter by letter

Secret letterCEFNUV
Real letterLNOWDE

Decode it with Python

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

secret = "NVCC UFEV!"
shift = 17
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:

WELL DONE!

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.