papers/zoo-wildlife-tracking/sections/06-smart-contract-access-control.tex

\section{Smart Contract Access Control}


\subsection{Contract Architecture}

The \WildTrack{} access control system is implemented as a set of composable smart contracts on the \Zoo{} network:

\begin{lstlisting}[basicstyle=\footnotesize\ttfamily, frame=single, caption={WildTrack access control interface (Solidity-like pseudocode).}]
interface IWildTrackAccess {
  // Data registration
  function registerTrajectory(
    bytes32 commitment,
    uint8 privacyTier,
    uint256 embargoEnd
  ) external returns (uint256 trajectoryId);

  // Access requests
  function requestAccess(
    uint256 trajectoryId,
    bytes32 purposeHash,
    uint8 requestedResolution
  ) external returns (uint256 requestId);

  // Access grants (by data owner)
  function grantAccess(
    uint256 requestId,
    bytes calldata encryptedKey
  ) external;

  // Time-delayed release
  function claimDelayedAccess(
    uint256 trajectoryId
  ) external view returns (bytes memory cloakedData);
}
\end{lstlisting}

\subsection{Role-Based Access}

The contract enforces four access levels:

\begin{table}[htbp]
\centering
\caption{Access levels and permissions.}
\label{tab:access}
\begin{tabular}{lllp{5cm}}
\toprule
\textbf{Role} & \textbf{Resolution} & \textbf{Delay} & \textbf{Use Case} \\
\midrule
Owner & Full & None & Data contributor \\
Collaborator & Full & Configurable & Research partners \\
Researcher & Cloaked & Tier-specific & General scientific use \\
Public & Aggregated & Maximum & Education, outreach \\
\bottomrule
\end{tabular}
\end{table}

\subsection{Anti-Poaching Emergency Protocol}

When a poaching event is detected (via anti-poaching sensor networks or ranger reports), the smart contract can trigger an emergency data lockdown:

\begin{equation}
\text{if}\; E_{\text{poach}}(r, t) \;\text{then}\; \forall \tau \in \mathcal{B}(r, R_{\text{lock}}) : \text{tier}(\tau) \leftarrow \text{Critical}
\end{equation}

This automatically elevates the privacy tier of all trajectories within radius $R_{\text{lock}}$ of the reported incident to Critical, increasing cloaking, delay, and access restrictions until the threat is resolved.