Lesson: [WIP] EV3 - Telegraph Machine: Basic Encryption

Printer-friendly version
This lesson introduces a simple XOR cipher used to encrypt telegrams. This can be easily extended to give an example of a one-time pad, and can show students the impracticality of pre-sharing such a key. This lesson teaches basic cryptography and also a common use of the boolean XOR operator.

After completing this lesson, students should be able to:

  • Describe why XOR is an elegant operation to encrypt/decrypt messages.
  • Define basic cryptographic vocabulary (e.g. key, plaintext, etc.).
  • Use a pre-shared key to exchange encrypted messages.
Education Level: 
Scope & Sequence: 
HW Platform: 
SW Platform: 
Interactivity Style: 
(C) 2015 Ernest Gu, CC-BY