In a Reddit post on Friday, Ethereum co-founder Vitalik Buterin (Ethereum), Overview Key security issues surrounding cross-chain bridges in the blockchain ecosystem.As Buterin said, direct on-chain storage of native assets (Ethereum on Ethereum, Solana on Solana, etc.) provides a degree of Immune to 51% attack. Even if hackers manage to censor or reverse transactions, they cannot come up with blocks to take one’s cryptocurrency.

However, Buterin went on to say that the same level of security does not apply to cross-chain bridges. In the example he presented, if an attacker deposits his own ETH into Solana (Sol) bridging to get Solana-wrapped ether (WETH), and then reverting that transaction on the Ethereum side as soon as the Solana side confirms it, which would be devastating for other users whose tokens are locked in the SOL-WETH contract because the wrapped code The coin is no longer backed by the original coin at a 1:1 ratio.

Buterin further outlines how the security hole can negatively expand as more bridges are added to the cross-chain network. In a theoretical network of 100 chains, a high degree of interdependence and overlapping derivatives means that a 51% attack on one chain, especially a small-cap chain, could lead to system-wide contagion. according to For Crypto 51, hackers spent a whopping $1.78 million per hour to launch 51% of the attack vectors on the Ethereum network. However, the cost of blockchains such as Bitcoin Cash fell to $13,846 per hour.

My argument for why the future will be *multichain*, but not *crosschain*: there are fundamental limitations to the security of bridges spanning multiple “sovereign regions”.from https://t.co/3g1GUvuA3A: pic.twitter.com/tEYz8vb59b

-vitalik.eth (@VitalikButerin) January 7, 2022

related: Vitalik proposes new ‘multi-dimensional’ Ethereum fee structure