Picture 1 (IMAGE) Singapore University of Technology and Design Caption Graphic of the new types of PUF that can be designed using the phase-change material (PCM), based on the reversible switching between the amorphous glassy state and orderly crystal state of a chalcogenide layer, along with sensing different as-deposited amorphous states, showing a large contrast in electrical and optical properties (top panel). Schematic of the product authentication concept (bottom panel). Credit Singapore University of Technology and Design Usage Restrictions Image should be used with appropriate caption and credit. 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.