The Based Sovereign Rollup
Last updated
Last updated
Like all Ethereum rollups, Facet’s state is derived from Ethereum L1 transaction history. However, Facet's fork of OP Stack incorporated key mechanisms from other existing Based Rollup and Sovereign Rollup architectures, resulting in a novel construction:
A BASED SOVEREIGN ROLLUP is a blockchain whose state is derived from transactions sequenced by L1 validators, with no dependency on privileged keys or enshrined contracts.
This new construct is the natural outcome of three design decisions that were necessary to preserve Ethereum's liveness, censorship resistance, and credible neutrality:
Elimination of centralized dependencies (e.g., sequencers)
Removal of all forms of privilege (e.g., upgradeable contracts, security councils, etc.).
Facet replaces OP’s centralized sequencer with a Based Rollup sequencing mechanism, adopting regular Ethereum transactions as the default method for submitting Facet transactions (similar to OP’s “deposit transactions”).
In a conventional rollup, users send their transactions on a separate network to centralized sequencers, giving a single entity (or set of permissioned EOAs) control over the transaction history relevant to the rollup.
Facet returns control over transaction history back to Ethereum’s validators with a decentralized sequencing mechanism that ensures transactions are ordered fairly and impartially, allowing the rollup to inherit the L1’s native resilience to censorship, reordering attacks and single-party MEV exploitation. This approach, known as "Based Sequencing," affords everyone equal ability to post transactions to the rollup's history.
”A rollup is said to be "based," or L1-sequenced, when its sequencing is driven by the base L1. More concretely, a based rollup is one where the next L1 proposer may, in collaboration with L1 searchers and builders, permissionlessly include the next rollup block as part of the next L1 block.”
- Justin Drake
Key Takeaways:
Users do not need to connect their wallet to a separate network to participate; they simply sign Facet transactions on Ethereum (UX).
If you can send an Ethereum transaction, you can send a Facet transaction (liveness).
No intermediaries can censor your transaction (censorship resistance).
With L1 sequencing, Facet unlocks native interaction scenarios with Ethereum’s deep liquidity (L1 composability).
While a based sequencing mechanism certainly enhances a rollup's ability to preserve Ethereum's liveness, censorship resistance and credible neutrality, it's not enough on its own.
How a protocol's rules get made (and upgraded) is just as important as the rules themselves.
Current rollups make their rules in a far more centralized and less secure way than the underlying Ethereum protocol itself. Every L2 currently involves a set of privileged private keys (the "security council" or multi-sig) that is capable of changing the rules of the rollup by fiat.
Facet adopts Sovereign Rollup principles by eliminating these privileged keys (e.g., security councils, multi-sig wallets) from the protocol, thereby avoiding the centralization risks that plague traditional rollups (e.g., bridge security, contract upgradeability, etc.). Facet’s purge of privilege is indiscriminate, even removing the enshrined (built-in) gas token bridge. This ensures a core protocol void of centralized authority of any kind, while still allowing developers to offer trust-minimized bridging at the application level.
Key Takeaways:
Like all rollups, Facet is defined by its State Transition Function (STF), the core logic defining how the rollup’s state changes with each new transaction. All of Facet’s code, including the STF, is transparent and mechanically free of bias (credible neutrality).
No central entity has the authority to upgrade or change how Facet operates; the only way to upgrade Facet is through social consensus and hard fork, just like Ethereum itself.
Of course, eliminating upgradeable contracts and privileged keys necessitates a novel approach to "gas"—which we'll cover below.
Gas payments are an essential part of a blockchain network's operations, playing a crucial role in preventing network spam attacks. Unfortunately, L2s introduce privilege via their native gas token. They do so by enshrining a mandatory bridge in the protocol: the ether gas token bridge. Users must deposit ether into an L1 bridge contract managed by the protocol in order to mint gas tokens on the L2. This gas bridge is operated by the L2's privileged keys (security council), granting the protocol operators incredible advantage/control within the network (upgradeability, fork-choice influence, etc.). Thus, adoption of these L2s inherently comes at the expense of L1 censorship resistance and credible neutrality.
To avoid introducing privilege via a native gas token, Facet adopts a mechanically neutral issuance mechanism for the native gas token: Facet Compute Token (FCT). Anyone can participate in minting FCT on Facet simply by sending Facet transactions on L1 Ethereum. There are no enshrined bridge contracts and no privileged keys that alter Facet's immutable FCT issuance mechanism. Moreover, there are no pre-mined or privileged allocations.
Key Takeaways:
At launch, all accounts are equal with null FCT balances (no pre-mines, no privileged allocations).
The only way to mint FCT is by sending Facet transactions on Ethereum. Anyone can participate.
FCT’s only enshrined utility is for paying gas fees to execute Facet transactions. As the Facet ecosystem matures, it’s logical to assume the native gas token will also drive future service economies on Facet (e.g., transaction batching, pre-confirmations, etc.).
By addressing key vectors of centralization and privilege introduced by conventional rollups, and by distributing the protocol's native gas token in a transparent, mechanically neutral way, Facet offers a way to scale Ethereum without sacrificing the very principles that make it special.
