According to CoinMeta, cross-chain bridges are systems designed to facilitate asset transfers between different blockchains. However, due to the isolation features of their security designs, these bridges have led to losses of up to $4 billion. Each blockchain has its own ledger and consensus rules, and users who hold assets on one chain wish to use those assets on another. The core of a cross-chain bridge lies in verification; if attackers can forge deposit information, they can mint unsupported tokens. Taking the Ronin bridge as an example, attackers successfully extracted 173,600 ETH and $25.5 million in USDC by controlling the private keys of multiple validators. This incident highlights the importance of multi-signature security; only when the independence of the signatories is sufficient can the multi-signature mechanism be effective.