Quantum Key Distribution
Quantum Key Distribution (QKD) uses the fundamental properties of quantum mechanics to establish shared secret keys between two parties with information-theoretic security. Unlike post-quantum cryptography (which relies on computational hardness assumptions), QKD security is guaranteed by physics itself: any eavesdropper necessarily disturbs the quantum states and is detected.
Major QKD Protocols
| Protocol | Year | Approach | Market Share |
|---|---|---|---|
| BB84 | 1984 | Prepare-and-measure, two conjugate bases | ~80% |
| E91 | 1991 | Entanglement-based, Bell inequality verification | Research |
| CV-QKD | 2000s | Continuous-variable, coherent states | Growing |
Key insight: QKD protocols use photonic hardware for quantum state transmission, but classical software handles everything else — authentication, error correction, privacy amplification, key management, and network orchestration. The classical-quantum software interface is where engineering meets physics.
The Canadian Quantum Landscape
Canada is positioning itself as a global leader in quantum communications through a combination of government programs, private companies, and university research groups.
Key Programs and Organizations
| Entity | Location | Focus |
|---|---|---|
| NRC QUIN | National | Quantum Internetworking Challenge program (2026–2033), building Canada's quantum network infrastructure |
| Photonic Inc. | Vancouver, BC | Silicon spin-photon qubits for distributed quantum computing; partnership with TELUS for commercial fiber networks |
| TELUS | Vancouver, BC | Commercial fiber infrastructure for quantum communications deployment |
| SFU Q-Van Lab | Burnaby, BC | Quantum Internet Systems Lab; Q-Van metropolitan testbed; QEYSSat satellite ground segment |
| Xanadu | Toronto, ON | Canada Quantum Network (CQN) testbed; photonic quantum computing |
| QEYSSat | National / Space | Canadian quantum communications satellite, launch expected late 2026 |
British Columbia Advantage
The Pacific Northwest offers a unique concentration of quantum communications capabilities:
- Photonic Inc. — developing silicon-based quantum processors with native photonic interfaces ideal for networking
- TELUS partnership — commercial-grade fiber infrastructure already in place for QKD deployment
- SFU Q-Van testbed — metropolitan quantum network connecting campus locations
- QEYSSat ground segment — SFU hosts a ground station for Canada's quantum satellite
Standards and Interfaces
The classical-quantum interface is defined by emerging standards that enable interoperability between QKD hardware from different vendors and integration with existing network infrastructure.
| Standard | Scope |
|---|---|
ETSI QKD 014 |
RESTful API for QKD key delivery (JSON/HTTPS) — the primary software interface |
ETSI QKD 004 |
Application interface for QKD key consumption |
ITU-T Y.3800+ |
Quantum network architecture framework |
From Theory to Infrastructure
Deploying quantum communications requires solving problems at every layer:
- Physical layer: Single-photon sources, detectors, and fiber/free-space channels
- Protocol layer: QKD protocol implementation, error correction, privacy amplification
- Key management: Storing, distributing, and rotating quantum-derived keys
- Network orchestration: SDN controllers for routing, trusted-node relay, and network topology management
- Application integration: Feeding QKD-derived keys into existing encryption systems (TLS, IPsec, VPNs)
NRC QUIN program (2026–2033) represents a $100M+ investment in building Canada's quantum network infrastructure. The Expression of Interest process opened in early 2026, with opportunities for testbed hosting, classical-quantum integration, and application development.
Complementary Technologies
QKD and PQC are complementary, not competing:
- QKD provides information-theoretic security for key exchange over dedicated channels
- PQC provides computational security that works over any network without specialized hardware
- Future networks will likely use both: QKD for high-security links, PQC for general-purpose encryption