A UUID (Universal Unique Identifier) is a 128-bit value used to uniquely identify information in computer systems. Commonly displayed as a string of hexadecimal digits separated by hyphens, UUIDs are generated using algorithms that ensure their uniqueness across space and time. In cybersecurity, UUIDs help distinguish users, devices, sessions, or objects, making them essential for tracking, authentication, and access control. Unlike sequential identifiers, UUIDs are difficult to predict, reducing the risk of enumeration attacks. They are widely used in databases, software development, and distributed systems to prevent identifier collisions and maintain data integrity.