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?
The secret message
DGF
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 wheels on a bicycle.
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 3 letters and starts with B.
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.