Files
zeekayandHanzo Dev 70f6883235 Restore the regulated-markets papers; Lux holds the licences
A July commit removed eight papers on the premise "no license — DEX/non-custodial
only". That premise is wrong: Lux operates an ATS, a broker-dealer, a transfer
agent and a bank, and this material is resold at lux.financial. The merge that
brought main in preserved the removal because the commit stated a reason, which
is how a stale reason outlives the fact it rested on.

Back, at the versions main carried — main never received the removal, so its
copies are the later ones: the ATS architecture, the security-token standard,
smart order routing, institutional custody, MPC custody, post-quantum securities,
the SSB partnership and the CoinBridge brief. 83 files.

Co-authored-by: Hanzo Dev <[email protected]>
2026-08-30 15:58:05 -07:00

65 lines
2.8 KiB
TeX

\section{Hybrid Migration Path}
\label{sec:hybrid}
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Immediate full migration to post-quantum signatures is impractical:
existing wallets, hardware devices, and tooling use ECDSA. The Lux
network implements a hybrid signature scheme for the transition period.
\begin{definition}[Hybrid Signature]
A hybrid signature on message $m$ is a pair
$(\sigma_{\text{ECDSA}}, \sigma_{\text{ML-DSA}})$ where:
\begin{itemize}[nosep]
\item $\sigma_{\text{ECDSA}} = \mathsf{ECDSA.Sign}(sk_{\text{ECDSA}}, m)$
\item $\sigma_{\text{ML-DSA}} = \mathsf{ML\text{-}DSA.Sign}(sk_{\text{ML-DSA}}, m)$
\end{itemize}
The chain accepts the transaction if \emph{either} signature verifies.
\end{definition}
\begin{theorem}[Hybrid Security: Best of Both Worlds]
\label{thm:hybrid}
The hybrid signature scheme is EUF-CMA secure as long as either
ECDSA (under the ECDLP assumption) or ML-DSA (under the MLWE/MSIS
assumptions) is EUF-CMA secure.
\end{theorem}
\begin{proof}
Suppose an adversary $\mathcal{A}$ forges a hybrid signature
$(\sigma^*_{\text{ECDSA}}, \sigma^*_{\text{ML-DSA}})$ on a new message
$m^*$. For the forgery to be accepted, at least one of
$\sigma^*_{\text{ECDSA}}$ or $\sigma^*_{\text{ML-DSA}}$ must verify.
If $\sigma^*_{\text{ECDSA}}$ verifies, then $\mathcal{A}$ has forged an
ECDSA signature, contradicting the ECDLP assumption. If
$\sigma^*_{\text{ML-DSA}}$ verifies, then $\mathcal{A}$ has forged an
ML-DSA signature, contradicting the MLWE/MSIS assumptions. Therefore,
the forgery probability is at most
$\epsilon_{\text{ECDSA}} + \epsilon_{\text{ML-DSA}}$, which is
negligible as long as either $\epsilon_{\text{ECDSA}}$ or
$\epsilon_{\text{ML-DSA}}$ is negligible.
\end{proof}
\subsection{Migration Phases}
\begin{enumerate}[nosep]
\item \textbf{Phase 0 (current).} Both classical and PQ precompiles
are available. Transactions may use either. Most users
continue with ECDSA.
\item \textbf{Phase 1 (recommended).} Wallets begin generating
hybrid key pairs (one ECDSA + one ML-DSA) and attaching hybrid
signatures to transactions. Either signature is accepted.
\item \textbf{Phase 2 (transition).} The chain begins requiring
ML-DSA signatures on high-value operations (e.g., token
issuance, validator registration). ECDSA remains valid for
standard transfers.
\item \textbf{Phase 3 (post-quantum).} When CRQCs are imminent or
operational, the chain deprecates ECDSA-only transactions.
Only ML-DSA or hybrid signatures are accepted.
\end{enumerate}
The key insight is that Phase~0 is already active: the precompiles
exist at genesis. No hard fork is needed to enable post-quantum
cryptography. The migration is purely a wallet-side upgrade.
%% =====================================================================