A system and method for providing external data-signal isolation, and signal-level information-preserving-data-transformations, to enable safe, operationally efficient, information sharing between protected information systems and networks and external, potentially hostile, information systems and networks which neutralizes any imbedded hostile executable codes such as viruses that may be in data-signals incoming from the external systems and networks. The system and method prevent untransformed external data-signals from entering protected systems and/or networks using an intermediate screen which is a computer hardware device. The intermediate screen is deployed between the protected systems and external systems and is used to process all incoming signals from the external system to obtain transformed data sets from which information is extracted before it is passed to the protected system.