A Comparison of Hybrid Classical + Post-Quantum Key Exchange Approaches
Explore how our hybrid classical + post-quantum key exchange compares to NIST Post-Quantum Cryptography standards
Classical (X25519 ECDH): well-vetted, decades of cryptanalysis
Post-Quantum (ML-KEM-768, NIST FIPS 203): resists Shor's algorithm
Combined via HKDF — breaking the final key requires breaking both, independently
The relay server never sees the pre-shared secret, either party's private key, or the derived key
Verified by an automated test proving a passive observer with everything actually transmitted still cannot derive the key
Ephemeral key material seeded from real IBM Quantum hardware randomness
Traceable to verifiable job IDs — not just an OS PRNG
Hybrid-friendly architecture
Layer on top of existing systems
No hard forks required
ML-KEM-768 is a NIST-standardized post-quantum algorithm, secure against known quantum attacks
Security rests on the hardness of the underlying math problems — not a claim of physics-guaranteed, unconditional security
Production SDK available
14 operational API endpoints
Entropy source validated on real quantum hardware
| Aspect | NIST PQC | Our Hybrid System |
|---|---|---|
| Security Basis | Computational hardness (lattice problem) | Computational hardness (ECDH + lattice, combined) |
| Key Material Size | ~2,272 bytes (ML-KEM-768 public key + ciphertext) | ~3,616 bytes total (adds X25519 material + MACs on top of ML-KEM-768) |
| Long-Term Guarantee | Secure until math breakthrough | Secure until both ECDH and the lattice problem break (defense-in-depth) |
| Migration Complexity | High (hard forks) | Hybrid-friendly (layer on top) |
| Proof of Security | Theoretical + standardization | Standard construction + automated test proving a passive relay observer cannot derive the key |
| Current Readiness | Software libraries ready | Production SDK; quantum-hardware-seeded entropy |
How our GHZ entanglement hardware research compares to traditional quantum key distribution implementations. This is a hardware-validation research result, not our production key exchange — see "Zero-Trust Hybrid Key Exchange" above for what's actually deployed.
| Aspect | BB84 | E91 | Our GHZ Research |
|---|---|---|---|
| Security Basis | Quantum no-cloning | Bell states | GHZ entanglement |
| Hardware Requirements | Quantum channel | Entangled photons | NISQ hardware |
| Range | Limited (~100km) | Limited (~100km) | Cloud-based (unlimited) |
| Fidelity | High (ideal conditions) | High (ideal conditions) | 35-94% (NISQ validated) |
| Scalability | Limited | Limited | 2-28 qubits validated |
| Production Use | Specialized hardware | Specialized hardware | 🔬 Research/demo — not the production key exchange |
Our hybrid system combines classical and post-quantum cryptography with quantum-hardware-seeded randomness — defense-in-depth security you can deploy today