Wiretap-Assisted Post-Quantum Key Agreement: Combining Physical-Layer Secrecy with PQ KEMs

Design a cross-layer authenticated key exchange (AKE) where a wiretap code (over Hamming or alternative metrics) pre-encodes randomness so that any leakage the adversary obtains is statistically bounded. Then a PQ KEM (lattice- or code-based) encapsulates the conditioned randomness. Provide proofs that the information-theoretic secrecy from the wiretap code composes with the computational security of the KEM. Optimize for constrained links using QKD-style post-processing reducers even without full QKD hardware. This approach fills the gap between classical wiretap secrecy and hybrid QKD-based schemes by offering a purely classical, channel-aware layer that measurably lowers the required KEM security margin and bandwidth with provable composition. It also reduces the leakage surface upstream, contrasting with brittle HQC-style KEMs vulnerable to oracle attacks. The research builds on secrecy over wiretap channels, post-processing efficiency, hybridization philosophy, and code-based primitives background. The impact is a new class of channel-aware PQ AKEs that bring information-theoretic secrecy benefits without QKD, suitable for legacy networks and critical infrastructure.

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