1. Post-quantum cryptography

Migration requires asset inventory, algorithm agility, hybrid deployment, certificate and protocol updates, vendor coordination, and long-term governance. Standardized algorithms are classical and can be deployed before quantum hardware matures.

Cryptographic transition is an enterprise architecture program, not a one-time software patch.

2. Networks and repeaters

Long-distance quantum networks require entanglement generation, memory, purification or error correction, routing, and interfaces. Quantum repeaters address loss without copying unknown states.

Networking progress depends on memories and interfaces as much as communication channels.

3. Sensing and metrology

Quantum-enhanced clocks, interferometers, magnetometers, gravimeters, and imaging systems can exploit coherence, squeezing, or entanglement. The relevant metric is sensitivity under real operating conditions, not laboratory precision alone.

Sensing is a distinct commercialization pathway with different engineering economics.

4. Applied activity

Advanced exercise: derive or simulate one representative result from this module, document assumptions, and produce a one-page technical interpretation for a non-specialist decision maker.