Visualize this: At a shop, you hand a 20 bill for a 10 item. The merchant gives you the item but keeps the surplus, leaving you shortchanged. ❓ That would be totally unfair, right? In Web3, sandwich attacks follow a similar pattern and hurt regular users at a rampant scale. The damage likely amounts to billions of dollars annually. So, what can be done to minimise this industry-plaguing issue? But first, what really happens behind the curtain for a better view. Sandwich attackers: 1) Monitor public mempool data 2) Identify pending inefficient trades w/ fat slippage 3) Frontrun with priority fee > this pushes the price up closer to the slippage limit of the victim, who ends up with fewer tokens received 4) Backrun in quick block succession The attack’s effectiveness is tied to how probable a successful frontrun is. Validators are incentivized to prioritize transactions with higher fees, which is a normal game theory behavior. However, the unfair advantage comes when the prioritisation is also applied to the execution order within the block. ❗️At MultiversX, we see this as the root problem and the key to addressing it. To make sandwich attacks and other harmful MEV types less feasible, we’ve implemented deterministic random transaction ordering since 2022. With it, validators no longer have control over arranging and sequencing transactions. The randomness source is unbiased, verifiable and taken from the previous block header. Try a sandwich attack on MultiversX and, by chance, you might end up being the one sandwiched 🤭 Quick review two years+ post-implementation: i) Bad MEV is a flaw, not a feature, and is solvable to a high extent ii) Sandwichers are not risk averse and avoid low-probability environments iii) TX randomness introduced unpredictability → raised cost to attack → reduced profit margins → drastically discouraged & minimized bad MEV on MultiversX iv) Users interact on-chain without the fear of invisible taxes v) Trust in on-chain markets is higher In certain industry circles, MEV is glorified and — checks notes — ripping off users is considered the only metric that matters. So it inevitably cheers us up to see that we are not alone in fighting to make user safety a priority in Web3. Well done on the progress @cz_binance & @BNBCHAIN!