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Cotmanhay Junior School

Safe, Happy Learning

Y5 Term 4 We are crypto- graphers

National curriculum content

Use logical reasoning to explain how some simple algorithms work and to detect and correct errors in algorithms and programs.


Lesson objectives

  1. Transmitting information in semaphore.
  2. Using Morse code.
  3. Using the Caesar cipher to create and crack codes.
  4. Password security.
  5. Security on the Web.


What we want children to know

  • Be familiar with semaphore and Morse code.
  • To understand the need for private information to be encrypted.
  • Encrypt and decrypt messages in simple ciphers.
  • Appreciate the need to use complex passwords and to keep them secure.
  • To understand how encryption works on the web.


What skills we want children to develop

  • Pupils use encryption and decryption in mathematical functions. Frequency tables play a role in cracking substitution ciphers.
  • Pupils explore interesting stories involving the use of cryptography throughout history.



Binary code, cipher, decrypt, encrypt, Morse code, password, security, semaphore