CREST Practitioner Security Analyst (CPSA) Practice

Which of the following protocols helps in the secure identity verification of nodes over a non-secure network?

1. Network Time Protocol

2. Post Office Protocol version 3

3. Kerberos

4. Remote Procedure Call

The correct answer is: Kerberos

The correct choice for secure identity verification of nodes over a non-secure network is Kerberos. This protocol is specifically designed to provide secure authentication and ensure that both users and services can verify each other’s identities before establishing a connection. Kerberos operates on the principle of tickets that are issued by a trusted third-party authentication server. When a client wants to access a service, it first requests a ticket from this server, which it uses to prove its identity to the service it wishes to access. This process protects credentials by ensuring they are never sent over the network in plaintext, thus providing strong protection against eavesdropping and replay attacks. In general, other options do not serve the same purpose. For instance, the Network Time Protocol is primarily used for clock synchronization rather than identity verification. The Post Office Protocol version 3 is designed for retrieving emails from a server and also lacks mechanisms for secure node identification. Finally, Remote Procedure Call focuses on allowing programs to execute code on a remote server rather than providing identity verification. This delineation underscores why Kerberos is the appropriate protocol for secure identity verification in this context.