Truly random numbers (IMAGE) University of Tokyo Caption When both sender and receiver have identical random numbers, they can share encrypted data without the need to share a key to decode it. This prevents so-called man-in-the-middle attacks. With COSMOCAT, muons (µ) arriving at the sender and receiver at the same time provide the source of the random number. Provided the devices are synchronized, the receiver can know which muon signal relates to which incoming message and can decode it accordingly. Credit ©2022 Hiroyuki Tanaka Usage Restrictions Credit must be given to the creator. License CC BY 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.