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Hack attack

Can you crack the hackers’ code to save technology, and use your own code to communicate with others on the mission?
Plan a session with this activity

You will need

  • Scissors
  • Split pins
  • A4 paper
Crack the code
JPG – 142.6KB
Crib sheet and decoder
PDF – 450.9KB
Crib sheet and crack the code (answers)
PDF – 128.9KB

A hacker has attacked, and left behind a coded message. It’s down to the group to create their decoders and solve the puzzle, to save technology as we know it.

Make the decoder

  1. Give everyone a 'Crib sheet and decoder' worksheet.
  2. They should use the scissors to cut out the two circles on the second page.
  3. Everyone should use a split pin to carefully make a small hole in the centre of each circle.
  4. Everyone should put the small circle on top of the big circle, with the letters facing them. They should line them up so that the holes in the middle are on top of each other.
  5. Everyone should push the split pin through the holes in both circles, and spread the pin so the circles are held together.

Set the decoder

  1. Once everyone’s nearly finished making their decoders, the person leading the game should pretend to check their phone, or an envelope they’ve ‘just found’, and reveal that they’ve just discovered a clue: the code is A = A.
  1. Everyone should think about what this clue may mean. Can they figure it out?

Crack the code

  1. Everyone should make sure their decoders are set up according to the clue – spun around so that 'A' on the bigger (outside) circle lines up with the right letter on the smaller (inside) circle.
  2. Everyone should find the first letter of the coded message on the bigger (outside) circle.
  3. Everyone should find the letter lined up with it on the smaller (inside) circle. This is the ‘real’ letter that had been turned into code.
  4. Everyone should write the real letter underneath the code letter that’s on their sheet.
  1. Repeat steps two to four for each letter on the sheet – it’s important to check each letter, and not guess, because guessing might mean you make mistakes.

Create your own code

  1. Everyone should write down the secret message they want to turn into code.
  1. Everyone should spin the smaller (inside) circle around and stop randomly. They should make a note of which letter on the smaller (inside) circle lines up with the A on the big (outside) circle.
  2. Everyone should find the first letter of their message on the inside (smaller) circle.
  3. Everyone should find the letter that lines up with it on the bigger (outside) circle. This is the code letter.
  4. Everyone should write down the code letter on another sheet of paper.
  1. Everyone should repeat steps three to five for each letter of their message.
  2. Once their messages are turned into code, people should swap secret messages with someone else, remembering to tell them how to set up their decoder.
  3. Everyone should follow the steps in ‘crack the code’ to find their friend’s message.
  4. Repeat these steps until everyone has created three messages for their friends to decode.


This activity helped you to communicate. When might using a code to communicate be helpful? What information did you need to give someone so they could figure out your code? Was it hard to keep your message really short? Could you say everything you wanted to, or did you have to pick and choose the most important things? Did you manage to crack your friends’ codes, and understand what they were trying to say?

This activity was also a chance to problem solve. What did you need to crack the code? Could you crack the code with just the decoder or the clue, or did you need both? Did you understand how the clue helped you, or did you need another clue about what it meant? Could you solve the problem quickly, or did you have to be patient when it was slow? Was it frustrating to check every letter when you were tempted to guess? Why was it important to still check things?



Supervise young people appropriately when they’re using scissors. Store all sharp objects securely, out of the reach of young people

Sharp objects

Teach young people how to use sharp objects safely. Supervise them appropriately throughout. Store all sharp objects securely, out of the reach of young people.

All activities must be safely managed. Do a risk assessment and take appropriate steps to reduce risk. Always get approval for the activity and have suitable supervision and an InTouch process.