Briefing
The core research problem in modular architecture is the centralization of Layer 2 sequencers, which creates single points of failure, censorship vectors, and risks to liveness. This paper introduces Based Sequencing , a foundational mechanism design that outsources rollup transaction ordering directly to the credibly neutral Layer 1 validator set, leveraging existing Proposer-Builder Separation (PBS) infrastructure. The breakthrough is the concept of “Based Preconfirmations,” which allows a competitive market of specialized gateways to provide sub-second transaction guarantees, fundamentally decoupling rollup performance from the sequencer’s centralization and establishing a path for L2s to inherit L1-level economic security and censorship resistance.
Context
The prevailing challenge for Layer 2 scaling solutions has been the “Sequencer Centralization Trilemma,” where a single, centralized entity is required to maintain high performance, offer fast pre-confirmations, and manage MEV, sacrificing decentralization and liveness. This design choice creates a critical security assumption → that the single sequencer will not fail or censor transactions, a reliance that undermines the L2’s overall trust model despite settling on a decentralized Layer 1.
Analysis
Based Sequencing re-architects the rollup stack by making the Layer 1 block proposer the de facto sequencer for all integrated rollups. The mechanism functions via an opt-in delegation model where Layer 2s use specialized “gateways” to gossip transactions and receive Based Preconfirmations → cryptographic promises of inclusion from the current or next Layer 1 proposer. This differs from previous approaches by using the Layer 1’s established security and PBS mechanism as a shared, credibly neutral sequencing layer, eliminating the need for Layer 2s to bootstrap their own separate, complex, and potentially less secure decentralized consensus network.
Parameters
- L1 Economic Security → Rollups inherit the full economic security of the underlying Layer 1 validator set, providing the highest possible security floor.
- Preconfirmation Latency → Optimized block pipelining and efficient gossiping enable execution preconfirmations within just a few milliseconds.
- Architectural Change → The solution requires no Layer 1 protocol-level changes or hard forks for immediate adoption.
Outlook
The immediate next step is the implementation and standardization of the Based Preconfirmations protocol across major rollup stacks. In the next three to five years, this theory could unlock a new wave of highly performant, maximally decentralized Layer 2 applications by solving the sequencer problem, enabling seamless atomic transactions across multiple “Based Rollups” that share the same Layer 1 sequencer, and shifting the focus of Layer 2 mechanism design entirely to execution and fraud/validity proving.
Verdict
Based Sequencing represents a foundational shift, transforming Layer 2 sequencers from a centralized security risk into a credibly neutral, economically aligned Layer 1 service.
