A host-based intrusion detection system (HIDS) produces a false alarm because of the abnormal behavior of users and the network. A host-based intrusion detection system (HIDS) is an intrusion detection system that monitors and analyses the internals of a computing system rather than the network packets on its external interfaces. A host-based Intrusion Detection System (HIDS) monitors all or parts of the dynamic behavior and the state of a computer system. HIDS looks at the state of a system, its stored information, whether in RAM, in the file system, log files or elsewhere; and checks that the contents of these appear as expected.
Answer option D is incorrect. A network intrusion detection system (NIDS) is an intrusion detection system that tries to detect malicious activity such as denial of service attacks, port scans or even attempts to crack into computers by monitoring network traffic. A NIDS reads all the incoming packets and tries to find suspicious patterns known as signatures or rules. It also tries to detect incoming shell codes in the same manner that an ordinary intrusion detection system does.
Answer option A is incorrect. IPS (Intrusion Prevention Systems), also known as Intrusion Detection and Prevention Systems (IDPS), are network security appliances that monitor network and/or system activities for malicious activity. The main functions of "intrusion prevention systems" are to identify malicious activity, log information about said activity, attempt to block/stop activity, and report activity. An IPS can take such actions as sending an alarm, dropping the malicious packets, resetting the connection and/or blocking the traffic from the offending IP address. An IPS can also correct CRC, unfragment packet streams, prevent TCP sequencing issues, and clean up unwanted transport and network layer options.
Answer option C is incorrect. DMZ, or demilitarized zone, is a physical or logical subnetwork that contains and exposes an organization's external services to a larger untrusted network, usually the Internet. The term is normally referred to as a DMZ by IT professionals. It is sometimes referred to as a Perimeter Network. The purpose of a DMZ is to add an additional layer of security to an organization's Local Area Network (LAN); an external attacker only has access to equipment in the DMZ rather than any other part of the network.

Confidentiality is a mechanism that ensures that only the intended and authorized recipients are able to read data. The data is so encrypted that even if an unauthorized user gets access to it, he will not get any meaning out of it.
Answer option A is incorrect. In information security, integrity means that data cannot be modified without authorization. This is not the same thing as referential integrity in databases. Integrity is violated when an employee accidentally or with malicious intent deletes important data files, when a computer virus infects a computer, when an employee is able to modify his own salary in a payroll database, when an unauthorized user vandalizes a web site, when someone is able to cast a very large number of votes in an online poll, and so on. There are many ways in which integrity could be violated without malicious intent. In the simplest case, a user on a system could mistype someone's address. On a larger scale, if an automated process is not written and tested correctly, bulk updates to a database could alter data in an incorrect way, leaving the integrity of the data compromised. Information security professionals are tasked with finding ways to implement controls that prevent errors of integrity.
Answer option B is incorrect. Data availability is one of the security principles that ensures that the data and communication services will be available for use when needed (expected). It is a method of describing products and services availability by which it is ensured that data continues to be available at a required level of performance in situations ranging from normal to disastrous. Data availability is achieved through redundancy, which depends upon where the data is stored and how it can be reached.
Answer option D is incorrect. Authentication is the act of establishing or confirming something (or someone) as authentic, i.e., the claims made by or about the subject are true ("authentification" is a variant of this word).