A Content Access Security Broker (CASB) is a security tool that provides oversight and control over the data and applications used in a cloud environment. It acts as a gatekeeper between cloud service users and cloud applications, enabling organisations to extend the reach of their security policies beyond their own infrastructure. CASB manages and secures data through various methods such as encryption, tokenisation, and access control, helping to prevent unauthorised access, data breaches, and other security threats. This technology is crucial for enterprises that utilise cloud-based services and seek to maintain compliance with data protection regulations.