In this chapter, we have seen what encryption, signing, and hashing are, and why they are relevant to you. We dove into how they work, to understand what possible threats are hidden in them. Then we moved to the PKI and certificate system to understand deeply how they work, and which vehicle of attacks is hidden there. In the last section, we saw how to secure OpenStack APIs.
In the next chapter, we will move on to securing the identification and authentication system of your OpenStack installation.