Quantum Networking & QKD
Where quantum links and key distribution actually help—and where they don’t—for crypto infrastructure, wallets, nodes, and bridges.
QKD: what it is (and isn’t)
What QKD does
- Uses quantum states (photons) to establish shared symmetric keys.
- Provides eavesdropping detection on the key exchange channel.
- Pairs with classical ciphers (e.g., AES-GCM) for data at-rest/in-flight.
What QKD does not do
- It does not replace digital signatures (auth, non-repudiation).
- It does not fix blockchain’s on-chain cryptography.
- It still needs authenticated channels to defeat MITM.
Where quantum networking helps vs. doesn’t (for crypto)
Helps
- Inter-datacenter links (custody, exchanges): high-assurance key refresh.
- Control planes between validators/oracles (out-of-band symmetric keys).
- Regulated environments needing “evergreen” key exchange channels.
Doesn’t help
- On-chain signatures (P2PKH, ECDSA, EdDSA): you still need PQC.
- Wallet auth & transactions: QKD doesn’t sign or verify.
- Public internet scale: current QKD is distance/line constrained.
Alternate path
- PQ key exchange (Kyber) over classical networks is deployable now.
- Hybrid: ECDH + Kyber for channel security; Dilithium/SPHINCS+ for signing.
- QKD optional: layer it only where the physical link is practical.
Adoption tracker
Use this as a living list of pilots and deployments. Replace the table below or embed via TablePress.
[table “qkd_adoption” not found /]| Org / Region | Use case | Distance / Medium | Status | Notes |
|---|---|---|---|---|
| Example Telco | DC-to-DC backbone keys | Metro fiber | Pilot | Placeholder rows — replace with your entries. |
| Example Exchange | Custody link hardening | Dark fiber | Planned | Evaluating vs. Kyber-based TLS |
FAQs
Do we still need PQC if we deploy QKD?
Yes. QKD doesn’t replace signatures or on-chain verification. Use PQC for signatures (Dilithium/SPHINCS+) and for classical channel KEM (Kyber).
Is QKD “unhackable”?
No. Real systems depend on optics, hardware, and authenticated channels; side channels and implementation bugs still apply.
When should crypto teams consider QKD?
Only for specific private links (custody, validator control planes) where fiber or satellite QKD is feasible. Otherwise use PQC over classical networks.