The disclosed embodiments provide a method and apparatus for protecting a critical computer system from malware intrusions. An isolator containing access approval features is disclosed. The isolator requires the approval of a Supervisor which can be a person with authority or an intelligent computer before a user can have access to the critical computer system. The isolator contains features used to facilitate cascaded encryption and decryption of messages which further enhances the security of the critical computer system. The isolator can greatly improve security of infrastructure such as industrial control systems, servers and workstations. The disclosed embodiments also provide a set of software and hardware features used to provide detection, prevention and recovery from a Cyber-attack in an Internet of Things installation.