Files
proofs/quasar/horizon-soundness.tex
zeekay 1430256d11 proofs: Lux liquidity protocol adoption + Quasar refs + Pulsar naming
Squashed batch covering:

- lux-adopts-liquidity-protocol.tex: protocol adoption proof artifact
- chronology updates aligning Quasar consensus references to LP-020
- pq-finality-no-bls.tex: Pulsar (Corona-derived lattice threshold)
  naming clarification; per-block / per-epoch / per-era cert language
- quasar-cert-soundness.tex: Pulsar (systems-layer composition with
  key-era lifecycle, resharing, activation cert, rollback) vs Corona
  (signing primitive); math notation and theorems unchanged
- INFRASTRUCTURE-STATUS-2026-04-20.md → INFRASTRUCTURE-STATUS.md
  (drop date stamp from filename)
- LP back-refs and chronology integration

quasar-cert-soundness.tex production-publishable depth (March 3 final):

  - NEW Section 6 (Pulsar Key-Era Lifecycle Lemmas): formal
    definitions for Pulsar share state, GroupKey hash, and Refresh /
    Reshare / Reanchor transitions. Four lifecycle lemmas with full
    proofs:
      Lemma 10 (Generation monotonicity)
      Lemma 11 (KeyEraID stability across Reshare)
      Lemma 12 (GroupKey byte-identity across Refresh and Reshare)
      Lemma 13 (Rollback-lineage forward reconstruction)
    Plus Theorem 14 (Activation-certificate soundness): VerifyActivation
    accepts iff the new committee shares Lagrange-recombine to the
    master secret under the unchanged GroupKey, except with negligible
    probability under MLWE/MSIS.
  - Lagrange-recombination identity written as a labelled display
    equation, citing
    Crypto.Threshold.Reshare.reshare_preserves_public_key in
    lean/Crypto/Threshold/Reshare.lean for the mechanised companion.
  - Bibliography additions: hjky97 (Herzberg--Jarecki--Krawczyk--Yung
    proactive secret sharing), desmedtjajodia97 (redistribution),
    wongwangwing02 (verifiable redistribution), lp073 (Pulsar paper).
  - LP-073 section pointers updated to text-form references that
    survive without LP-073 .aux file.

Naming evolution: throughout this work, "Corona" refers to the
lattice signing primitive (Sign1/Sign2/Combine math); "Pulsar" refers
to the Lux production fork at github.com/luxfi/pulsar that wraps it
with key-era lifecycle for permissionless validator-set rotation.

- proofs/fhe/ (NEW): canonical proof bucket for the Lux FHE
  dual-runtime stack (LP-167 companion):
    correctness.tex             — encrypt → evaluate → decrypt correctness.
    dual-runtime-equivalence.tex — Lux FHE-Go and Lux FHE-C++ produce
                                   byte-equal output on identical inputs
                                   and parameters; KAT closure witness.
    nebula-binding.tex          — FHE result roots bind into Nebula /
                                   Quasar transcripts; reduces a forged
                                   binding to hash collision + Pulsar
                                   SUF-CMA forgery.
    parameter-security.tex      — concrete LWE parameter security under
                                   the Albrecht estimator; ≥128-bit
                                   classical and ≥128-bit quantum for
                                   PN10QP27 / PN11QP54 / PN9QP28_STD128.
  Theorem statements + remarks; no proof bodies duplicated in the
  companion paper (papers/lux-fhe-runtime/) — the paper cites these.
2026-03-03 12:00:00 -08:00

47 lines
2.1 KiB
TeX

%% ============================================================
%% quasar/horizon-soundness.tex
%% ============================================================
%%
%% Canonical Horizon (Prism-bound) soundness theorem.
%% ============================================================
\subsection*{Horizon soundness}
\begin{theorem}[Horizon-final implies all lanes verify the same transcript]
\label{thm:horizon-soundness}
Let $\mathsf{cert}$ be a Horizon certificate
(Definition~\ref{def:horizon-cert}) with
$\mathsf{Prism}(\mathsf{cert}) = 1$. Then the underlying validator set
of size $n$ with $f < n/3$ corruptions cannot have produced a Horizon-
final certificate for two distinct $\mathsf{NebulaRoot}$ values at the
same epoch and round, except with negligible probability under:
\begin{enumerate}[nosep]
\item BLS12-381 co-CDH (for the Beam lane);
\item Module-LWE / Module-SIS (for the Pulsar lane,
Theorem~\ref{thm:pulsar-suf-cma});
\item EUF-CMA security of ML-DSA-65 / FIPS 204 (for the ML-DSA cert
set lane).
\end{enumerate}
The proof is by independent reduction: any pair of Prism-accepted certs
on conflicting bundle roots forces a forgery in at least one lane.
This is independent across the three lanes (different hardness
assumptions); a quantum adversary breaking BLS does not break Pulsar
or ML-DSA, and vice-versa.
\textbf{Companion proof:} \texttt{quasar-cert-soundness.tex} Theorem
7.5 (classical soundness), 7.6 (parallel-lane liveness), 7.7 (PQ
safety).
\end{theorem}
\begin{remark}[Groth16 wrapper does not contribute PQ security]
\label{rem:groth16-wrapper}
A Z-Chain Groth16 rollup proof of ML-DSA cert-set verification
(Definition~\ref{def:proof-lane}) is a \emph{classical succinct proof of
post-quantum signature verification}. The proof system is
pairing-based and is not post-quantum. Horizon's PQ soundness
(Theorem~\ref{thm:horizon-soundness} parts 2 and 3) flows from the
ML-DSA signatures and Pulsar threshold signature alone; the Groth16
proof is verified for compatibility / compression only and is not part
of the PQ reduction. See Remark~\ref{rem:groth16-not-pq}.
\end{remark}