Schematic of our FP-MDIQKD protocol (IMAGE) Science China Press Caption At Alice’s (Bob’s) site, the simplified transmitter contains a laser source and an encoder. The encoder modulates the phase of the optical pulses. The modulation information of the encoder should be monitored to characterize the deviation between ideal and realistic pulses. If the untrusted Charlie is honest, he measures the signals received using an interference measurement. Credit ©Science China Press Usage Restrictions Use with 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.