Censorship Resistance & Inclusion Lists

The Quiet Censorship Risk

One of a blockchain's core promises is censorship resistance: if you pay the fee, your valid transaction should get included, and no one should be able to permanently keep you out. In practice, that promise has come under subtle pressure. Because block-building has become concentrated among a small number of specialised builders (partly a side-effect of MEV and proposer-builder separation), those builders can choose to exclude certain transactions — for example, to comply with regulatory sanctions lists. If most blocks are built by parties that all skip the same transactions, a user could find their valid transaction ignored block after block. This is not censorship by the protocol, but censorship emerging from centralisation in who assembles blocks.

Inclusion Lists: Forcing the Door Open

An inclusion list is a mechanism to fight this. The idea is that validators (who are more numerous and decentralised than builders) can specify a list of pending transactions that must be included in an upcoming block. A builder is then not allowed to produce a valid block that ignores those transactions if there is room for them. In effect, inclusion lists give the decentralised set of validators a way to force otherwise-excluded transactions into blocks, restoring the guarantee that if your transaction is valid and you pay, it cannot be quietly filtered out by a handful of block builders. It is a targeted fix for censorship that arises from block-building centralisation.

• Censorship resistance: valid, fee-paying transactions should always be includable
• Concentrated block-building lets a few builders exclude specific transactions
• Inclusion lists let decentralised validators require certain transactions be included
• Builders can't produce a valid block that ignores listed transactions when there's room