LP-0175Proposedpqml-kemkemsessionhandshake

LP-175: Session KEM

Abstract

LP-175 mirrors HIP-0088 into Lux. The Lux ZAP handshake under

LUX_STRICT_PQ performs an ML-KEM-768 (FIPS 203 NIST PQ Cat 3,

default) or ML-KEM-1024 (Cat 5, high-value) encapsulation, with

mutual ML-DSA-65 signatures over the handshake transcript. The derived

shared secret is run through KMAC256 (SP 800-185) to produce a 256-bit

AEAD key.

Mirrored profile


ProfileID:           0x01  (ProfileLuxStrictPQ)
ProfileName:         LUX_STRICT_PQ
HashSuiteID:         SHA3_NIST                (0x01)
IdentitySchemeID:    ML_DSA_65                (0x42)
KEMSchemeIDDefault:  ML_KEM_768               (0x01)
KEMSchemeIDHighValue: ML_KEM_1024             (0x02)
MinSoundnessBits:    128
MinHashOutputBits:   384
RequireTransparent:  true
ForbidPairings:      true
ForbidKZG:           true
ForbidTrustedSetup:  true
ForbidClassicalSNARKs: true
ForbidDevProofs:     true
ForbidFallbacks:     true

Lux-specific bindings

Canonical KEM ID registry: luxfi/consensus/config/pq_mode.go

(KeyExchangeID). The auth-package surface re-exports the same

bytes via type alias (luxfi/consensus/protocol/auth/scheme_ids.go).

KEM session primitives: luxfi/node/network/kem/scheme.go +

mlkem.go. Handshake state machine: luxfi/node/network/peer/handshake.go.

Lux validator-to-validator gossip on LUX_STRICT_PQ MUST use

ML-KEM-768 minimum; high-value mesh roles (bridge, governance MPC)

use ML-KEM-1024.

Session key rotation: 1 hour or 2^28 records.
Classical X25519 is refused under LUX_STRICT_PQ; hybrid

constructions are admissible only on permissive profiles for legacy

interop.

Compliance

A Lux node on LUX_STRICT_PQ MUST NOT negotiate X25519 or ECDH. The

KEM scheme byte is bound into the handshake transcript and into the

AEAD-key derivation; substitution is detected at the TupleHash256

binding step.

References

HIP-0088 — canonical source of truth.
LP-022 — ZAP wire baseline.
LP-072 — ML-KEM primitive.
NIST FIPS 203, FIPS 204, FIPS 202, SP 800-185, SP 800-57.
luxfi/consensus/config/pq_mode.go — canonical KeyExchangeID.
luxfi/node/network/kem/, luxfi/node/network/peer/handshake.go.