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

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Overview: 
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.
Objectives: 

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.
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(C) 2015 Ernest Gu, CC-BY