Lab 6: The Vigenère Cipher

Open Lab Notebook in Google Colab

Learning Objectives

1. Extend the Caesar cipher to the Vigenère cipher, which shifts each letter by a different amount from a repeating keyword.

2. Count coincidences to measure how well a candidate distance matches repeating structure.

3. Use coincidence counts to determine the most likely key length of a Vigenère-ciphered message.

Lab Outline

• Vigenère Encryption
• Finding the Key Length
• Exercises