Chain Replay Attack

A Chain Replay Attack occurs when a valid transaction intended for one blockchain is intercepted and maliciously rebroadcasted on a different chain. This is possible if both chains share the same transaction structure and lack unique identifiers to distinguish between them.

In financial terms, an attacker could withdraw collateral on one chain and then replay the transaction on another to drain funds repeatedly. To prevent this, protocols implement chain-specific data in transaction signatures, ensuring that a signature valid on chain A is mathematically invalid on chain B. This protection is vital for maintaining the integrity of decentralized exchanges and lending platforms operating across multiple networks.