% Table 1: Dimensional taxonomy of blockchain anomalies and frauds
% Columns: Anomaly/Fraud class | Blockchain layer | Detection method | Example incident | Reference
\begin{table*}[!htbp]
\centering
\caption{Dimensional taxonomy of blockchain anomalies and frauds. Each row indexes a representative anomaly or fraud class by the blockchain layer at which it manifests (Network, Consensus, Contract, or Application), the detection method family most applicable to its signature (Statistical, Machine-Learning, Game-Theoretic, or Digital-Forensic), an exemplar real-world incident, and a primary scholarly reference. The taxonomy is intended to serve as a lookup table for practitioners selecting a detection technique for a specific attack class; it is not exhaustive but covers the principal categories reviewed in this paper.}
\label{tab:taxonomy}
\small
\begin{tabular}{@{}p{3.2cm}p{2.0cm}p{3.2cm}p{3.6cm}p{2.2cm}@{}}
\toprule
\textbf{Class} & \textbf{Layer} & \textbf{Detection method} & \textbf{Example incident} & \textbf{Reference} \\
\midrule
Network outage / partition & Network & Statistical (traffic TS) & Ethereum mempool stalls & Kim et al. 2021 \\
Eclipse / sybil attack & Network & Graph anomaly + ML & Bitcoin eclipse PoC & Akoglu et al. 2015 \\
Selfish mining & Consensus & Game-theoretic & Theoretical, not observed at scale & Baqer et al. 2016 \\
51\% attack & Consensus & Statistical + forensic & Ethereum Classic 2020 & Ron \& Shamir 2013 \\
Reentrancy exploit & Contract & Static + dynamic analysis & DAO 2016 & Atzei et al. 2017 \\
Authorization bypass & Contract & Static + ML (code-emb) & Poly Network 2021 & Liang et al. 2021 \\
Flash-loan attack & Contract + App & ML (price-TS + graph) & bZx 2020, Harvest 2020 & Qin et al. 2021 \\
Rug-pull / exit scam & Contract + App & ML (token-lifecycle) & Numerous DeFi tokens & Mazorra et al. 2022 \\
Double-spending & Consensus + App & Statistical + forensic & Historical Bitcoin attempts & Ron \& Shamir 2013 \\
Transaction malleability & Consensus + App & Forensic reconciliation & Mt. Gox 2014 & Decker \& Wattenhofer 2014 \\
Pump-and-dump & App (market) & ML (price + volume TS) & Various altcoin campaigns & Kamps \& Kleinberg 2018 \\
Wash trading & App (market) & Graph + ML & Exchange-level & Mansourifar et al. 2020 \\
Money laundering / mixing & App & Graph + clustering & Multiple & Monamo et al. 2016 \\
Exchange exit scam & App (exchange) & Forensic + off-chain audit & QuadrigaCX 2019 & Ron \& Shamir 2013 \\
Cross-chain bridge exploit & Cross-chain & Graph + authorization ML & Poly 2021, Ronin 2022 & Liang et al. 2021 \\
\bottomrule
\end{tabular}
\end{table*}
