The Global Centre for Risk and Innovation (GCRI)
Quantum communications use quantum states of light to distribute encryption keys with security rooted in physics, and in future to link quantum computers and sensors in networks. Quantum key distribution works over limited distances and needs dedicated hardware and trusted nodes today. This page sets out how quantum communications work, what they can and cannot secure, and what evidence serves the network operators and security agencies weighing them.
GCRI · In development · service level R0
Quantum communication is the transmission of quantum states, usually of light, to share encryption keys or link quantum devices. Quantum key distribution detects eavesdropping through disturbance, but distance limits, trusted relay nodes and implementation attacks shape its real security, and wider quantum networks remain in research.
For quantum communications, in GCRI's spatial-intelligence reading, the map opens on night lights, true-colour imagery and population density with true colour from NASA GIBS, framed on Japan and Korea; every other NASA layer, live feed and forecast waits in the layer list.
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NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
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For quantum communications, in GCRI's spatial-intelligence reading, the map opens on night lights, true-colour imagery and population density with true colour from NASA GIBS, framed on Japan and Korea; every other NASA layer, live feed and forecast waits in the layer list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.
Layers and dates
The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.
Quantum communications · Crypto inventory · Wave 2
| Archive signing | RSA-2048 | 28 | ML-DSA hybrid | Piloting |
| VPN gateway | ECDH | 9 | ML-KEM hybrid | Planned |
| Payments HSM | RSA-3072 | 11 | Vendor roadmap | Blocked |
| Web TLS | ECDHE | 2 | Hybrid key exchange | Done |
Communications research and deployment limits. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
In quantum key distribution, measuring a quantum state disturbs it, so an eavesdropper introduces detectable errors. Keys are kept only when error rates are low.
Photons are lost in fibre, limiting direct links. Longer networks use trusted relay nodes or satellites, each with security implications.
Real devices deviate from ideal theory. Side-channel attacks on detectors and sources have been demonstrated, so security depends on implementation and certification.
Distributing entanglement between distant nodes needs quantum repeaters and memories, which are still in research.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Trusted node | A relay in a QKD network where keys exist in classical form and must be protected. |
| Quantum repeater | A device that would extend quantum communication by entanglement swapping and storage. |
| Side-channel attack | An attack exploiting physical imperfections of a device rather than its theoretical design. |
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| QKD link distance | kilometres | per demonstration | Published experiments | REPORTED |
| Secret key rate | bits per second at a stated distance | per demonstration | Published experiments | REPORTED |
| Deployed QKD network nodes | count | annual | Operator and government reports | REPORTED |
| Security evaluations completed for QKD products | count | annual | Evaluation scheme records | OFFICIAL |
| Quantum memory storage time | milliseconds | per experiment | Peer-reviewed results | OBSERVED |
| Satellite QKD demonstrations | count | annual | Agency reports | REPORTED |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| ETSI ISG QKD specifications | Component, interface and security specifications | Public, ETSI terms |
| ITU-T Y.3800 series | Network recommendations for QKD | Public, ITU terms |
| National cyber agency positions on QKD | Agency views on QKD versus post-quantum cryptography | Public, terms per agency |
| EuroQCI programme documentation | European quantum communication infrastructure plans | Public, EU terms |
| Peer-reviewed quantum communication literature | Experimental results | Licence per article |
Quantum Technologies prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Network operators | Whether QKD fits any of their links and threat models | Use comparisons; architecture reviews |
| National cyber agencies | What position to take on QKD for government use | Implementation security evidence |
| Research funders | How to fund quantum network research | Progress on memories and repeaters |
Communications questions weigh physical security against practical limits.
Quantum key distribution relies on the principle that measuring a quantum state disturbs it, so two parties can detect an eavesdropper and agree a secret key. The security of the ideal protocol rests on physics rather than on assumptions about computational difficulty. Real systems, however, use imperfect sources and detectors, and several attacks have exploited those imperfections.
Photons are absorbed and scattered in fibre, which limits direct links to relatively short distances. Longer networks currently rely on trusted nodes, where the key is held in classical form and must be protected conventionally. Quantum repeaters, which would extend range without trusted nodes, remain a research goal. Satellites have been used to demonstrate links over long distances.
| Method or data | What it shows | Limits |
|---|---|---|
| Security proofs | Theoretical security of protocols | Proofs assume idealized devices |
| Implementation testing and quantum hacking research | Vulnerabilities in real equipment | Testing cannot prove the absence of flaws |
| Network trials | Performance, key rates and operations | Trials are limited in scale and duration |
| Comparative security assessment | When quantum or post-quantum approaches fit | Depends on threat model and system constraints |
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.