In Ethereum with [PBS](, the block builders are the ones fixing the ordering of transactions. They try to maximize MEV in orders to gain advantage over other builders. And in a rollup world the sequencer is the one responsible for ordering and can therefore extract all MEV.(Epecially after decentralized sequemcers are introduced) > But what if all transactions are encrypted/hidden until it gets added or the ordering is fixed? - A user proposes a encrypted transaction with fees visible. - The sequencer builds a block, bundling the transactions with highest fees and adds it to the chain. without executing any transactions. Now the ordering of transaction is fixed and no one can change it. - After a specified amount of time the transaction data is revealed and executed. The execution can **succeed** or it can **fail**. ## Encrypted sequencing unlocks New Usecases when should be the transactions get revealed? If this parameter is configurable buy the user, for example set to 1 block, or 1 day. A dex will probably use few blocks to prevent frontrunning or sandwich attacks. New applications like Sealed bid auction are now easy to implement. By configuring the transaction to get revealed after the auction ends. ### Possible problems - **One can spam with invalid transactions:** If the gas fees for the transactions is not returned to user(even in-case of reverts), the spammer will lose money and needs to waste gas to censor the chain, similar to eth. - .... WIP