Answer: Secret Code #147

The secret message says:

PLANE

The shift was 19.

The secret note decoded: PLANE
The note, decoded.

Letter by letter

Secret letterEGITX
Real letterLNPAE

Decode it with Python

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

secret = "IETGX"
shift = 19
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:

PLANE

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.