In cybersecurity, a 'black box' refers to any device, system, or software whose internal processes are unknown or hidden from the user. This means that only the inputs and outputs are visible, while the way it operates internally remains concealed. Black box systems can be intentionally designed this way to protect intellectual property or enhance security, making it difficult for outsiders to analyze, reverse-engineer, or tamper with the system. This concept is also used in 'black box testing,' where testers evaluate a system’s functionality without any knowledge of its internal structure. Understanding black boxes is important for assessing trust, transparency, and potential vulnerabilities in technology.