Page 123 - Kaleidoscope Academic Conference Proceedings 2021

Connecting physical and virtual worlds

Table 1 – Procedure for device-independent quantum
randomness source

Step 1. Setting parameter.
1) Assign the least target amount of entropy (bits) to be
generated;
2) Assign the security parameters;
3) Under the QPE framework, determine a valid randomness
witness for later randomness evaluation.
Step 2. Randomness generation experiment.
1) Run the Bell test experiment;
2) Use the QPE method to evaluate the generated randomness
Figure 1 – The schematic demonstration of the DIQRNG.
in a real-time manner;
of the loophole-free Bell inequality test has very high 3) If the randomness evaluation succeeds, goto Step 3.
requirements for the measurement of entangled sources and Otherwise, abort the protocol.
quantum states. Although entangled atomic systems are Step 3. Randomness extraction.
expected to violate Bell’s inequality significantly [22, 23], Apply a quantum-proof strong extractor to the raw data of the
the current event rate of these systems during experiments Bell test and obtain near-uniform random bits under the given
is very low and it is almost impossible to obtain sufficient security parameter.
experimental statistics in a reasonable time frame. Another
technological route is the entangled photon-based system The raw data containing quantum randomness is obtained
[7, 8, 9, 26, 27, 28, 29] with a high event rate, which makes using a loophole-free Bell test. The final step is randomness
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it possible to implement DIQRNG. extraction. With the security parameter of = 2 ,
quantum randomness can be extracted using a quantum-proof
extractor to obtain a uniform number of random bits, the exact
3.1 DIQRNG setup
value of which is determined according to practical needs.
Otherwise, the protocol will be aborted.
Figure 1 shows the schematic diagram of DIQRNG. This
system should include three parts: entanglement source,
3.3 The technological maturity of DIQRNG
quantum measurement, and quantum random extraction. The
entanglement source distributes the prepared entangled pairs
The prototype of DIQRNG has been developed in
to two measurement stations. The measurement stations
the laboratory. At present, the generation rate of
need to randomly select a measurement basis vector to
device-independent quantum random numbers can achieve to
measure the received photons. The two measurement
more than 10000bits/s [18], and there is still much room for
events need to satisfy a space-like relationship to ensure
improvement in the future. However, due to the high threshold
that the two events are independent of each other. The
of the DIQRNG technology, the large size of the equipment
measurement results are used as raw data and the final
and the high cost, it is difficult to carry out large-scale
random bits are extracted by an anti-quantum extractor. Using
promotion. In terms of the technology, DIQRNG is ready
a high-performance entanglement source and an efficient
to serve the public. Combined with the Internet, beacon
random entropy evaluation theory, the randomness of the
services are provided as a public service to help strengthen
output can be greater than the random seed, thus enabling
information security in cyberspace.
randomness expansion. Only the randomness expansion can
make the value of DIQRNG practical.
4. RANDOMNESS BEACON
3.2 DIQRNG protocol Randomness beacon [30] is an important use case
that combines random number generation techniques and
Currently, there are two protocols: Entropy Accumulation networking. It can be understood as a platform that
Theory (EAT) [24] and Quantum Probability Estimation periodically distributes a trusted source of random entropy
(QPE) [25], which can effectively implement DIQRNG and to most users. Randomness beacons need to satisfy three
also resist quantum side channel attacks. Taking QPE as requirements: unpredictability, autonomy, and consistency.
an example, the process of DIQRNG is shown in Table 1. Unpredictability means that the value of a random bit cannot
The process can be divided into three main steps. The first be predicted before it is generated. Autonomy requires that
step is to determine the parameters, especially the Quantum the source of randomness to be able to resist any external
Estimation Factor (QEF) which plays an important role in attempts to change the random outcome. Finally, consistency
randomness evaluation. It can be used to calculate the requires that a group of users can receive the same sequence
iterator for estimating the generated randomness in real of random bits. DIQRNG can ensure the unpredictability
time during the randomness generation process. If the of the random sources and avoid malicious manipulation
iterator exceeds a threshold, randomness evaluation can be of quantum devices from outside, so it is most suitable for
achieved. The second step is to generate the randomness. random beacon’s entropy source.

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