Quantum randomness
Random means not being able to know in advance what will happen, even when the possibilities are known. Random data is essential in fields such as cryptography. Computers can generate pseudo-random value sequences using deterministic algorithms. For many applications this is sufficient, but not when real unpredictability is required. Truly random events are difficult to produce and verify. Quantum mechanics provides a natural source because quantum events are fundamentally unpredictable. A quantum random number generator, or QRNG, converts measured quantum events into truly random data for use by applications that require it.
What you are seeing
The QRNG produces bytes with a random value from 0 through 255. In uniformly random data, each value is expected about 0.391% of the time. The bars will fluctuate: randomness does not mean that every value occurs exactly equally often.
- Duration
- 10 s
- Elapsed
- 0.0 s
- Bytes sampled
- 0
- Mean
- —
- Standard deviation
- —
- Experiment state
- Ready
Ready
What is quantum here?
The QRNG is a compact but fairly complex device. Inside of it, a controlled light source emits photons toward a sensor. Even when the average light level is steady, the exact number of photons emitted and detected during each tiny sampling interval fluctuates unpredictably. This shot noise arises from the quantum nature of light: individual photon-emission and detection events have probabilities, but their precise outcomes cannot be predicted. The sensor converts those fluctuations into an electrical signal, which is digitized into raw values.
The device continuously checks that the measured noise remains dominated by the quantum process rather than by ordinary electronic or environmental noise. The raw data is then conditioned to remove bias and produce a uniform stream of random bits. This conditioning removes small imbalances and patterns from the raw measurements, producing an even stream of zeros and ones without creating randomness itself; quantum uncertainty remains the single source of randomness.
The resulting bits are sent to the computer through USB and combined into the byte values shown in this experiment.
About the QRNG
- Location
- Bladel, the Netherlands
- Device status
- —
- Model
- Not available
- Firmware
- Not available
- Quantum source
- Not applicable
- Output rate
- —