3.8 Summary
In this chapter, we have introduced the most important cryptographic notions and concepts revolving around keys, including entropy and randomness. We have seen that we should use different keys for different purposes and that they should be regularly updated. We also learned that the length of a key should depend on the half-life of the information the key is supposed to protect.
In the next chapter, we will see how keys are used together with cryptographic algorithms to encrypt and decrypt secret messages. We will even see an example of a truly unbreakable cipher.
