Dark Ledger: The Crypto Routes That Launder Billions

Cryptocurrencies have introduced a new paradigm of global, permission-less value transfer. While these features enable innovation, they simultaneously create opportunities for laundering illicit proceeds at unprecedented speed and scale. This paper examines the mechanisms through which money laundering occurs in the cryptocurrency ecosystem, mapping the laundering lifecycle, discussing the tools and services widely exploited by criminal actors, and analysing real-world laundering playbooks that blend on-chain techniques with off-chain intermediaries. Case studies reveal how mixers, OTC brokers, pseudo-anonymous marketplaces, cross-chain infrastructure, and decentralised finance (DeFi) protocols facilitate the placement, layering, and integration of illicit crypto funds. The paper concludes by assessing emerging countermeasures and the inherent policy tradeoffs between privacy, innovation, and effective financial surveillance.