Secret Code #105

Secret Code 105 card

Challenge type: Secret Codes  ·  Difficulty: ★★★☆☆ Medium  ·  Code: Shift code

Pixel left Beep a secret note, but it’s written in a shift code. Can you work out what it says?

Secret code 105. The note says: MCTWWTLYE!
Decode the secret note.

The secret message

MCTWWTLYE!

How the code works

This is a shift code. Every letter was moved forward in the alphabet by the same number of places. Here’s a riddle to tell you how many: the shift is the number of players in a football team.

Count that many letters backwards for each secret letter. If you go past A, carry on from Z.

Need a hint?

The first word of the answer has 10 letters and starts with B.

Safety first: Secret codes are great fun with friends and family. But remember: never keep a secret from your grown-ups that makes you feel worried or uncomfortable.

For teachers and grown-ups

Skills practised: Algorithms, encoding and decoding, and logical reasoning (cryptography basics).

The big idea: A cipher is an algorithm. Knowing the method and the key lets you undo it.

Questions to ask:

  • What does the key (the shift) do?
  • How could you crack a shift code without knowing the key?
  • Why are simple codes like this not safe for real secrets?

Take it further: Make the paper code wheel from our printables and send messages between groups.