BlocksInform
in a reddit post on friday, vitalik buterin, the co-founder of ethereum (eth), outlined critical security concerns surrounding cross-chain bridges in the blockchain ecosystem. as told by buterin, storing native assets directly-chain (ethereum on ethereum, solana on solana, etc.) provides a certain degree of immunity against 51% attacks. Even though hackers manage to censor or reverse transactions, they cannot propose blocks to remove its crypto.
The rule applies equally to the ethereum application. For example, if hackers launch a 51% attack (controlling 51% of the entire supply flow) while an investor swaps 100 eth for 320,000 dai stablecoin, the end state remains unchanging. In other words, the investor would still get either 100 eth or 320,000 dai.
However, buterin continued, that the same level of safety does not apply to transverse decks. in the example he raised, if an attacker deposited their own eth onto a solana (sol) bridge to obtain solana-wrapped ether (weth) and then reverted that transaction on the ethereum side as soon as the solana side confirmed it, it would incur devastating losses on other users whose tokens are locked in the sol-weth contract, as the wrapped tokens are no longer backed by the original on a 1:1 ratio.
Buterin went on to explain how safety operations could expand negatively as more bridges are added to an inter-channel network. In a theoretical network including 100 channels, the high level of interdependence and overlapping derivatives would mean that a 51% attack on a chain, especially a little beanie, can cause contagion across the system. according to crypto 51, it costs as much as $1.78 million an hour for hackers to mount a 51% attack vector against the ethereum network. However, the cost drops to as little as $13,846 an hour for blockchains such as bitcoin money.
my argument for why the future will be *multi-chain*, but it will not be *cross-chain*: there are fundamental limits to the security of bridges that hop across multiple "zones of sovereignty". from https://t.co/3g1guvua3a: pic.twitter.com/teyz8vb59b
— vitalik.eth (@vitalikbuterin) january 7, 2022
