Exercise 8: Encryption


Following the introduction to transmitting messages on task sheet 6, this task sheet deals with protecting the transmission by encryption. Two simple encryption methods introduce the way substitute ciphers work and the concept of key-controlled encryption.


How can data transmission be protected against “eavesdroppers”? How does encryption work? What is a “key”?


Learning objective

  • Encryption as the key to stop “eavesdropping”
  • Principle of “joint secret”
  • Principle of a key-based cipher
  • Programming encrypted transmission
  • Determining the “key range” of a cipher

Time required

The model from task sheet 6 (transmitter/receiver, telegraph station) can be used. One to two school hours are needed to solve the two tasks.

Didactic material