What constitutes a data breach?

A data breach is defined as an incident in which unauthorized individuals gain access to protected data, resulting in potential exposure or misuse of sensitive information. This can occur through various means, including hacking, employee negligence, or even physical theft of devices containing secure data. When protected data, such as personally identifiable information (PII) or financial records, is accessed without appropriate permission, it constitutes a breach, leading to legal consequences, loss of trust, and potential financial losses for organizations.

In contrast, an improvement in data security systems or a successful software update does not represent a data breach; rather, these actions are preventive measures designed to safeguard data. Accessing encrypted data without authorization suggests a serious security risk, but it becomes unequivocally a breach only when it results in the unauthorized exposure of sensitive information. Therefore, the key aspect of a data breach lies in the unauthorized access to protected data itself, which is well captured by the correct answer.