Explanation: Integrity refers to the ability to ensure that the data is not modified or tampered with. Integrity means that data cannot be modified without authorization. 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. Answer: D is incorrect. Confidentiality is the property of preventing disclosure of information to unauthorized individuals or systems. Breaches of confidentiality take many forms. Permitting someone to look over your shoulder at your computer screen while you have confidential data displayed on it could be a breach of confidentiality. If a laptop computer containing sensitive information about a company’s employees is stolen or sold, it could result in a breach of confidentiality. Answer: B is incorrect. Availability means that data must be available whenever it is needed. Answer: C is incorrect. Non-repudiation is the concept of ensuring that a party in a dispute cannot refuse to acknowledge, or refute the validity of a statement or contract. As a service, it provides proof of the integrity and origin of data. Although this concept can be applied to any transmission, including television and radio, by far the most common application is in the verification and trust of signatures.