DeFi, short for decentralized finance, describes financial services built on blockchain systems and operated through software such as smart contracts, rather than managed by a single central intermediary. Examples include systems for exchanging tokens, lending, and borrowing. Users typically interact with these services through blockchain wallets.
DeFi matters in cybersecurity because control and enforcement can be distributed across software, wallets, and blockchain networks. In an attack, criminals may use DeFi services to move or exchange stolen assets, while investigators may face challenges applying procedures designed for centralized platforms. Defenders assess smart-contract vulnerabilities, wallet security, and transaction activity; investigations and asset seizures also need to account for the limits of controlling assets without a central service provider.