Shielded Virtual Machines are a type of virtual machine designed to enhance security in cloud environments. They use encryption and other protective measures to ensure that the operating system and applications running inside the virtual machine are secure from unauthorized access and tampering. These virtual machines are particularly useful for sensitive workloads, as they help protect data and applications from threats. By leveraging technologies like BitLocker for disk encryption and Virtual Trusted Platform Module (vTPM) for secure key management, Shielded Virtual Machines provide a robust defense against various cyber threats.