Summary

In this chapter, we learned about what TLS certificate pinning is and in which situations it can be helpful. We also learned how to implement TLS certificate pinning with the help of a certificate verification callback. Then, we learned about the differences between blocking and non-blocking sockets and how to use non-blocking network connections. After that, we learned how to use OpenSSL memory BIOs to establish TLS connections over non-standard sockets. This knowledge can help you to write more secure, responsive, and performant applications, as well as to adapt your programs to embedded OSes.

In the next chapter, we will learn how to run a mini-CA that can issue certificates for internal usage within an organization.