Summary

In this chapter, we learned about the concept of X.509 certificates, why are they needed, and what kind of information they contain. We also learned about certificate signing chains and their role in certificate verification. Then we learned about CAs, as well as the differences between root and intermediate CA certificates. We also learned about the process of issuing X.509 certificates and several types of certificates, such as domain validation and EV types. Then we learned about X509v3 extensions. We finished the theoretical part of the chapter by learning about the concept of PKI.

In the practical part of the chapter, we learned how to generate self-signed and non-self-signed certificates. Then, we learned how to verify certificates, both on the command line and programmatically using C code.

In the next chapter, we will learn about setting up TLS connections and sending data over them.