Unit of 3 lessons aimed at KS3 Year 7 in England. Students learn about cryptography and undertaking practical unplugged activities to develop their logical reasoning and problem-solving skills. They write algorithms for a Caesar cipher and are introduced to writing Caesar ciphers in text-based programming using JavaScript and Python. This unit forms the second part of the cyber security unit, though it can be used on its own and can be a good introduction to text-based programming, or a way to extend existing knowledge. The lesson sequence comprises 3 lessons of approx. 60 minutes: Introducing cryptography today and in history (World War Two) Caesar cipher algorithms unplugged activity Creating Caesar cipher programs with text-based programming . Learning objectives can understand and apply the fundamental principles & concepts of computer science (logic, abstraction, algorithms, real world problem analysis and problem solving). practical experience of writing computer programs to solve problems. are responsible, competent, confident and creative users of information and communication technology . Additional skills Problem-solving, collaboration, critical thinking, creative thinking, prototyping, presenting, researching. . Included resources Lesson plan Word docs Lesson slides PowerPoints Student handouts Program files . England KS3 Computing curriculum links design, use and evaluate computational abstractions that model the state and behaviour of real-world problems and physical systems use logical reasoning to compare the utility of alternative algorithms for the same problem use two or more programming languages, at least one of which is textual, to solve a variety of computational problems make appropriate use of data structures (for example, lists, tables or arrays); understand simple Boolean logic (for example, AND, OR and NOT) and some of its uses in circuits and programming; understand a range of ways to use technology safely, respectfully, responsibly and securely, including protecting their online identity and privacy; recognise inappropriate content, contact and conduct and know how to report concerns.