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zeekayandHanzo Dev
70f6883235
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]>
83 lines
3.1 KiB
TeX
83 lines
3.1 KiB
TeX
\section{2-of-3 Wallet Architecture}
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\label{sec:wallet}
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%% =====================================================================
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Each user's wallet uses a $2$-of-$3$ threshold with the following share
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distribution:
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\begin{table}[h]
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\centering
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\begin{tabular}{clp{7.5cm}}
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\toprule
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\textbf{Share} & \textbf{Holder} & \textbf{Role} \\
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\midrule
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$\mathbf{s}_1$ & User device & Stored in device secure enclave
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(iOS Keychain / Android Keystore) \\
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$\mathbf{s}_2$ & ATS operator & Auto-co-signs after pre-trade compliance
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(KYC, AML, sanctions, offering checks) \\
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$\mathbf{s}_3$ & Cold backup & Encrypted to user passphrase, stored in
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Shamir backup (S3 + user's custody) \\
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\bottomrule
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\end{tabular}
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\caption{2-of-3 share distribution for user wallets.}
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\label{tab:shares}
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\end{table}
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\begin{theorem}[Non-Custodial Guarantee]
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\label{thm:non-custodial}
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No single party can produce a valid signature. Specifically:
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\begin{enumerate}[nosep]
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\item The ATS operator alone cannot move user assets (holds only
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$\mathbf{s}_2$; needs $\mathbf{s}_1$ or $\mathbf{s}_3$).
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\item The user alone cannot bypass compliance (holds only
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$\mathbf{s}_1$; needs $\mathbf{s}_2$ or $\mathbf{s}_3$).
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\item A compromised backup alone is useless (holds only
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$\mathbf{s}_3$; needs $\mathbf{s}_1$ or $\mathbf{s}_2$).
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\end{enumerate}
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\end{theorem}
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\begin{proof}
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By the unforgeability of the threshold signing protocol
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(Theorem~\ref{thm:cggmp-uf} for CGGMP21,
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Theorem~\ref{thm:frost-uf} for FROST), producing a valid signature
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requires at least $t = 2$ shares. Each party holds exactly one share.
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Therefore no single party can sign. This holds information-theoretically
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for the secret sharing layer (any single share is uniformly random,
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independent of the key) and computationally for the signing protocol
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(under the OMDL/ECDSA assumptions).
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\end{proof}
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\subsection{Signing Flows}
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\textbf{Normal transaction (user + operator):}
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\begin{enumerate}[nosep]
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\item User initiates transaction on their device.
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\item Device generates partial signature using $\mathbf{s}_1$.
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\item ATS operator receives request, runs pre-trade compliance checks.
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\item If compliant, operator generates partial signature using
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$\mathbf{s}_2$.
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\item Signatures are combined into a standard on-chain signature.
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\end{enumerate}
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\textbf{Device lost (operator + backup):}
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\begin{enumerate}[nosep]
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\item User proves identity through KYC re-verification.
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\item Backup share $\mathbf{s}_3$ is recovered using the user's
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passphrase.
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\item Operator co-signs with $\mathbf{s}_2$ to authorize a reshare
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that generates a new $\mathbf{s}_1$ for the replacement device.
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\item The on-chain address does not change (reshare preserves the
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aggregate public key).
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\end{enumerate}
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\textbf{Operator compromise (user + backup):}
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\begin{enumerate}[nosep]
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\item User activates emergency recovery using device share
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$\mathbf{s}_1$ and backup share $\mathbf{s}_3$.
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\item Funds are moved to a new threshold address with a fresh
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operator share.
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\end{enumerate}
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%% =====================================================================
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