Quantum Communication

1935 · 91 years ago

Einstein, Podolsky and Rosen described the correlations later known as quantum entanglement

Their paper, intended as a critique of quantum mechanics, identified the correlated particle pairs that would later become the physical resource underlying quantum key distribution, decades before any communications application existed.

1964 · 62 years ago

John Bell formulated the theorem that made entanglement experimentally testable

The Northern Irish physicist derived an inequality that any local hidden-variable theory must satisfy, giving experimentalists a concrete test that would later distinguish genuine quantum entanglement from classical explanation.

1982 · 44 years ago

Alain Aspect experimentally confirmed the violation of Bell's inequalities

The French physicist's experiments showed that entangled particles behaved in ways no theory based on hidden local variables could explain, settling a decades-old debate and confirming that entanglement was a real, usable physical resource.

1984 · 42 years ago

Charles Bennett and Gilles Brassard proposed the BB84 protocol, the foundation of quantum key distribution

The American and Canadian computer scientists showed that the act of measuring a quantum state necessarily disturbs it, meaning any eavesdropper on a quantum-encoded key would leave a detectable trace, a principle that remains the basis of quantum cryptography today.

1989 · 37 years ago

Charles Bennett and collaborators ran the first experimental demonstration of quantum key distribution

The experiment transmitted a secure key across roughly 30 centimetres of open air on an IBM laboratory bench, a modest distance that nonetheless proved the BB84 protocol could work outside theory.

1991 · 35 years ago

Artur Ekert proposed an alternative protocol based on entanglement rather than single photons

The Oxford-based physicist showed that shared entangled pairs, rather than the transmission of individually prepared photon states, could also generate a provably secure key, broadening the theoretical basis for quantum key distribution beyond the original protocol.

2001 · 25 years ago

Id Quantique was founded in Geneva as one of the first quantum cryptography companies

The spin-off from the University of Geneva began selling quantum key distribution hardware commercially, helping establish Switzerland as an early centre of the nascent quantum communication industry alongside later entrants in North America and Asia.

2004 · 22 years ago

Researchers in Vienna secured a bank transfer using quantum key distribution

A payment between a bank and Vienna's city hall was encrypted using keys generated and distributed by quantum key distribution equipment, an early demonstration that the technology could move beyond the laboratory into a real financial transaction.

2015 · 11 years ago

A team at Delft University of Technology closed the last loopholes in tests of quantum entanglement

Researchers in the Netherlands demonstrated entanglement between electrons more than a kilometre apart while ruling out the detection and locality loopholes that had left earlier experiments open to alternative explanation, a result that underpinned later device-independent security proofs.

2017 · 9 years ago

China's Micius satellite linked Beijing and Vienna in a secure video call

The satellite distributed quantum keys to ground stations on two continents, and researchers in China and Austria used them to secure an intercontinental video call, the clearest practical demonstration to date of satellite-based quantum key distribution.

• Micius had reached orbit the previous year

2025 · last year

The EU's EuroQCI initiative continued rolling out national quantum communication testbeds

Member states progressed pilot fibre links under the programme, while the European Space Agency's Eagle-1 satellite, intended to add a space segment to the network, continued development amid a timeline that had slipped from its original target.

• Eagle-1 was originally planned for launch earlier in the decade

2025 · last year

Toshiba expanded commercial deployment of its quantum key distribution systems

Building on earlier installations securing data-centre and financial-sector links in Japan, the UK and the US, the company continued marketing quantum key distribution hardware as a near-term commercial product rather than a research demonstration.

2025 · last year

South Korea continued integrating quantum key distribution into telecom and government networks

Telecom operators built on earlier commercial quantum key distribution deployments, extending quantum-secured links across metropolitan fibre networks and into pilot use for protecting selected public-sector communications.

2025 · last year

Singapore's SpeQtral advanced development of a small satellite for quantum key distribution

The company, spun out of the National University of Singapore's quantum research centre, worked toward extending quantum-secured communication beyond fibre-optic range, part of a small but active Southeast Asian push into satellite quantum communication.

2025–2026 · this year

US Department of Energy national laboratories extended entanglement-based quantum network testbeds

Argonne, Fermilab and other national laboratories continued building out metropolitan-scale quantum network links, working toward the interconnected nationwide quantum internet outlined in the Department of Energy's earlier blueprint.

2025–2026 · this year

China continued extending its integrated satellite-and-fibre quantum network

Metropolitan quantum-secured networks in additional cities were linked to the existing Beijing-Shanghai backbone and satellite relay capability, with quantum-secured links reported in increasing use for selected government, banking and energy-sector communications.

2025–2026 · this year

India's National Quantum Mission advanced its quantum communication hub toward long-distance targets

The government-backed programme continued funding research toward satellite-based quantum key distribution across long ground-station separations and fibre-based links strung with trusted relay nodes, part of an eight-year mission covering computing, communication, sensing and materials.

• The mission set targets running to 2031

2024–2025 · last year

US security agencies continued to advise against relying on quantum key distribution for national security systems

Guidance maintained that quantum key distribution's need for trusted nodes and specialised hardware left it impractical and vulnerable compared with post-quantum cryptography, keeping the United States a comparative outlier among states investing heavily in QKD infrastructure.

2024–2025 · last year

Russia extended its state-backed quantum key distribution network

Fibre links secured with quantum key distribution, developed with Russian Railways infrastructure and the Russian Quantum Center, were extended toward additional cities, with domestic banks named among the early users of quantum-secured connections.

2024–2025 · last year

Chinese and South African researchers reported a satellite-based quantum key exchange spanning the two countries

The collaboration extended satellite-based quantum key distribution to an intercontinental link between Asia and Africa, building on China's earlier satellite quantum communication work and marking one of the first such demonstrations to include an African research partner.

• The result fed into wider Chinese quantum diplomacy