Smart Contracts in the Real World: A Statistical Exploration of External Data Dependencies
Smart contracts’ reliance on external data introduces significant security and reliability risks, yet systematic empirical studies remain scarce. To address this gap, we conduct the first large-scale statistical analysis of 9,356 real-world smart contracts, integrating abstract syntax tree parsing, keyword matching, manual annotation, and mining of professional security audit reports to construct the first structured database of external dependencies. We propose a reproducible framework for identifying and classifying such dependencies, revealing a statistically significant positive correlation between contract complexity and external dependency intensity. Our analysis uncovers 249 vulnerabilities directly attributable to external data handling—constituting 9% of all reported vulnerabilities in the audited datasets. These findings provide critical empirical evidence and foundational infrastructure to support secure smart contract development, formal verification, and security auditing practices.