Abstract
Quantum random number generators (QRNGs) can significantly improve the security of cryptographic protocols by ensuring that generated keys cannot be predicted. However, the cost, size, and power requirements of current Quantum random number generators have prevented them from becoming widespread. In the meantime, the quality of the cameras integrated in mobile telephones has improved significantly so that now they are sensitive to light at the few-photon level. We demonstrate how these can be used to generate random numbers of a quantum origin.
1 More- Received 2 May 2014
DOI:https://doi.org/10.1103/PhysRevX.4.031056
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Published by the American Physical Society
Popular Summary
Random numbers play an essential role in securing modern communications; cryptographic keys should be generated randomly to ensure that they cannot be guessed. However, computers are deterministic devices, incapable of generating true randomness. On the other hand, random number generators based on the laws of quantum mechanics can generate random bits in a provable way. Since random number generators typically require specialized hardware, such as single-photon detectors, they are rarely accessible to consumers. We show that it is actually possible to generate random numbers with a quantum origin using consumer-grade hardware, such as the image sensors included in many computers, tablets, and mobile phones.
The image sensors in many consumer devices are able to detect at the few-photon level, and they can resolve the quantum noise needed to generate genuinely random numbers. We demonstrate this fact on both a CCD camera and a Nokia mobile phone illuminated by a LED. We adjust the level of illumination to maximize quantum uncertainty in the number of detected photons (without exceeding the linear regime of the detector). The raw data from the detectors are sent to an extractor that condenses the randomness of each pixel into approximately 3 bits with a very high-quality randomness.
Our method enhances the security of generated cryptographic keys and prevents attacks on security systems that rely on exploiting weaknesses in their random number generators. By showing that consumer devices have reached a state where they can directly be used for the implementation of some quantum technologies, we expect that our results will impact information security.