Lesson 1: Secret codes

In the first lesson of this unit, pupils explore a variety of different codes from simple Caesar ciphers to the Enigma code

Before the lesson

Download classroom resources

Learning objective

  • To understand that there are lots of different types of secret codes

National curriculum

Pupils should be taught to:

  • Solve problems by decomposing them into smaller parts
  • Use logical reasoning to explain how some simple algorithms work and to detect and correct errors in algorithms and programs

Success criteria

Cross-curricular links

Attention grabber

Main event


Pupils needing extra support: Should be directed towards the clues available for each code to help lead them towards solving them.


Pupils working at greater depth: Should be encouraged to make connections between the codes they have looked at.

Wrapping up

Assessing pupils' progress and understanding


Created by:
Cat Lamin,  
Computing specialist
Cat was a committed primary school teacher for twelve years. After starting her independent consultancy ‘Crossover Solutions’ she has travelled to Argentina, Brazil and America to share her wealth of knowledge of computer science with other teachers. Her enjoyment for…
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