A cross-chain bridge is a service or protocol that lets users move crypto assets from one blockchain to another. Because blockchains do not natively share state, a bridge typically locks, mints, burns, or releases tokens so value can exist on the destination chain in a usable form.
In cyber security, bridges matter because they are common targets and common tools in laundering. Attackers may send stolen funds through multiple chains to create extra hops, frustrate blockchain tracing, and reach services with weaker controls. Defenders watch bridge contracts, wallet clusters, and rapid chain-to-chain movement for signs of obfuscation. Good controls include transaction monitoring, sanctions screening, and fast coordination with analytics providers and exchanges before assets exit the trail.