What does the term 'IPsec' refer to?

The term 'IPsec' stands for Internet Protocol Security, which refers to a comprehensive suite of protocols that are used to secure Internet Protocol (IP) communications. By providing authentication, confidentiality, and data integrity at the IP layer, IPsec ensures that data being transmitted across a network is secure from eavesdropping and tampering.

IPsec operates using two main modes: transport mode, which encrypts only the payload of the IP packet, and tunnel mode, which encrypts the entire IP packet. This functionality is critical for establishing Virtual Private Networks (VPNs), as it allows for secure and private communication over public networks.

Other choices listed do not accurately represent IPsec. For instance, the option referring to a network addressing protocol does not align with IPsec's security functions, while describing it as an encryption standard for data oversimplifies its role and scope. Lastly, calling it a routing protocol misclassifies its purpose entirely, as routing protocols deal with the paths that data takes through a network rather than securing data in transit. Therefore, C, Internet Protocol Security, effectively captures the essence and primary function of IPsec.