Optical Communication Channel (IMAGE) Karlsruher Institut für Technologie (KIT) Caption Schematic representation of the hidden optical communication channel, via which a physically isolated system may be attacked. (Figure: KASTEL/KIT) Credit KASTEL/KIT Usage Restrictions . License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.