papers/lux-sovereign-defi/sections/05-securities-compliance.tex

\section{Securities Compliance}

\label{sec:securities}
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\subsection{The Cross-Chain Securities Problem}

Security tokens issued under ERC-3643 (T-REX)~\cite{erc3643} maintain on-chain compliance registries that enforce:

\begin{enumerate}[nosep]
  \item \textbf{Investor identity}: KYC/AML verified addresses in an identity registry.
  \item \textbf{Jurisdiction}: Country-level transfer restrictions (e.g., US accredited investors only).
  \item \textbf{Lockup}: Time-based transfer restrictions (e.g., 12-month hold after issuance).
  \item \textbf{Accreditation}: Investor qualification (e.g., net worth, income thresholds).
  \item \textbf{Capacity}: Maximum number of holders or per-holder limits.
\end{enumerate}

When a security token is bridged via a conventional protocol, these constraints are stripped. The bridge token on the destination chain has no compliance registry, enabling unrestricted transfer to non-qualified addresses. This violates securities law in every major jurisdiction.

\subsection{Compliance-Preserving Teleport}

Teleport introduces a compliance-preserving bridge mode for ERC-3643 tokens:

\begin{definition}[Securities Bridge Mode]
\label{def:securities}
For a security token $T$ with compliance registry $\mathcal{R}_T$ on source chain $\Chain_s$, the securities bridge mode:
\begin{enumerate}[nosep]
  \item Deploys a mirrored compliance registry $\mathcal{R}_T'$ on destination chain $\Chain_d$.
  \item The MPC signer set attests to registry state, synchronizing $\mathcal{R}_T'$ with $\mathcal{R}_T$.
  \item The bridge token on $\Chain_d$ enforces the same transfer restrictions as $T$ on $\Chain_s$.
  \item Registry updates propagate cross-chain within one attestation period.
\end{enumerate}
\end{definition}

\subsection{Compliance State Machine}

Each security token transfer follows a state machine with compliance checks at every transition:

\begin{figure}[h]
\centering
\begin{tikzpicture}[
  node distance=1.8cm,
  state/.style={rectangle, rounded corners, draw, minimum width=1.6cm, minimum height=0.8cm, font=\scriptsize, align=center},
  arrow/.style={-{Stealth[length=2mm]}, thick},
  label/.style={font=\scriptsize, text=black!70}
]
  \node[state] (init) {Initiated};
  \node[state, right of=init, xshift=0.8cm] (kyc) {KYC\\Verified};
  \node[state, right of=kyc, xshift=0.8cm] (lock) {Locked};
  \node[state, below of=kyc, yshift=-0.4cm] (attest) {MPC\\Attested};
  \node[state, below of=lock, yshift=-0.4cm] (mint) {Minted\\(Compliant)};
  \node[state, below of=init, yshift=-0.4cm] (reject) {Rejected};

  \draw[arrow] (init) -- node[above, label] {check $\mathcal{R}_T$} (kyc);
  \draw[arrow] (kyc) -- node[above, label] {escrow} (lock);
  \draw[arrow] (lock) -- node[right, label] {$\sigma$} (mint);
  \draw[arrow] (kyc) -- node[left, label] {attest} (attest);
  \draw[arrow] (attest) -- node[below, label] {sync $\mathcal{R}_T'$} (mint);
  \draw[arrow] (init) -- node[left, label] {fail} (reject);
\end{tikzpicture}
\caption{Securities compliance state machine. Transfers require KYC verification on both source and destination chains before minting.}
\label{fig:compliance-sm}
\end{figure}

\subsection{Compliance Registry Interface}

\begin{lstlisting}[language=Solidity,caption=IComplianceRegistry interface]
interface IComplianceRegistry {
    // Identity verification
    function isVerified(address investor)
        external view returns (bool);
    function getCountry(address investor)
        external view returns (uint16);

    // Transfer compliance
    function canTransfer(
        address from,
        address to,
        uint256 amount
    ) external view returns (bool);

    // Lockup enforcement
    function getLockupEnd(address investor)
        external view returns (uint256);

    // Accreditation
    function isAccredited(address investor)
        external view returns (bool);

    // Capacity
    function holderCount()
        external view returns (uint256);
    function maxHolders()
        external view returns (uint256);
}
\end{lstlisting}

\subsection{Settlement Registry}

For regulatory reporting, Teleport maintains a settlement registry that records every cross-chain security token transfer with sufficient detail for audit:

\begin{definition}[Settlement Record]
\label{def:settlement}
A settlement record $\rho = (T, \Chain_s, \Chain_d, \text{from}, \text{to}, a, t, \sigma, \text{complianceHash})$ contains the token, source and destination chains, sender, recipient, amount, timestamp, MPC signature, and a hash of the compliance state at the time of transfer.
\end{definition}

The settlement registry is append-only and indexed by token address and time range. Regulators can query the registry to reconstruct the complete transfer history of any security token across all chains.

\subsection{Regulatory Compatibility}

\begin{table}[h]
\centering
\small
\begin{tabular}{@{}p{2cm}p{4.8cm}@{}}
\toprule
\textbf{Regulation} & \textbf{Teleport Compliance Mechanism} \\
\midrule
MiCA~\cite{mica2023} & Cross-chain identity registry sync, transaction reporting via settlement registry \\
\addlinespace
SEC Reg D & Accredited investor checks enforced on destination chain; lockup periods preserved \\
\addlinespace
SEC Reg S & Country-code transfer restrictions; US persons blocked on non-exempt chains \\
\addlinespace
AAOIFI & ShariaFilter + SAB classifications; on-chain fatwa references \\
\addlinespace
ERC-3643 & Full T-REX registry mirroring; compliance agent role preserved cross-chain \\
\bottomrule
\end{tabular}
\caption{Regulatory framework compatibility.}
\label{tab:regulatory}
\end{table}

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