Summary

In this chapter, after setting up Python, we covered the simple substitution cipher, the Caesar cipher, and then base64 encoding. We gathered data six bits at a time instead of eight bits at a time, and then we looked at XOR encoding, where bits are flipped one by one in accordance with the key. We also saw a very simple truth table. The challenges you performed were cracking the Caesar cipher without the key, cracking base64 by reversing it to get the original bytes, and cracking XOR encryption without knowledge of the key with a brute-force attack trying all possible keys. In Chapter 2, Hashing, we will cover different types of hashing algorithms.