Client and node authentication

Authentication is the process of verifying the identity of a system that is making a request. In the context of CockroachDB, this can be a client executing queries on a CockroachDB cluster or the nodes in a cluster that are talking to each other. Authentication can be achieved by using certificates and keys. Let's look at an example. Let's assume that foo and bar want to talk to each other and that before they start talking, they want to ensure they are talking to each other. First, we must understand the concept of public-private keys. Any message that you encrypt with a public key can be decrypted using its corresponding private key. This pair is supposed to be unique in that no other key can be used for decryption. Also, they have to be different. The following diagram shows how public key encryption works:

Figure 9.1 – Public key encryption

So, going back to our example, foo and bar have a pair of public and...