Device-independent quantum random-number generation

Abstract

Randomness is critical for many information processing applications, including numerical modelling and cryptography^1,2. Device-independent quantum random-number generation (DIQRNG)^3,4 based on the loophole-free violation of Bell inequality produces unpredictable genuine randomness without assumptions on the inner working of devices and is therefore an ultimate goal in the field of quantum information science^5–7. Previously reported experimental studies of DIQRNG^8,9 were not proven to be secure against the most general attacks. Here we present fully functional DIQRNG against both quantum and classical adversaries^10–12. By exploiting the state-of-art quantum optical technology, we achieve an efficiency of more than 78 per cent from creation to detection of entangled photon pairs at a distance of about 100 metres, which largely exceeds the efficiency threshold besides satisfying the no-signaling condition to realize a robust loophole-free violation of Bell inequality. This allows us to realize the security analysis of the Bell test outcomes against the general quantum side information and without assuming independent and identical distribution. As a demonstration, by applying a large Toeplitz matrix (137.90 Gb × 62.469 Mb) hashing technique, we obtain 6.2469 × 10⁷ quantum-certified random bits in 96 hours or 181 bits per second with a total failure probability within 10⁻⁵, marking a critical step to bring DIQRNG from the concept towards practical applications. We anticipate that our work may help in understanding the origin of randomness from a fundamental perspective, and also in generating genuine randomness for practical applications demanding better security levels⁷.