2025-06-13 –, Side Stage - Cinema 7
Rebased rollups introduce a novel paradigm blending the advantages of based and non-based rollups to provide synchronous composability, credible neutrality, and reduced latency without incurring the full cost and latency penalties associated with Ethereum-based rollups. By becoming "based on-demand" for durations shorter than a full Ethereum slot, rebased rollups efficiently utilize Ethereum’s existing proposer set to facilitate faster transaction confirmations and increased throughput.
This presentation explores the technical challenges posed by current Layer 2 (L2) rollups, particularly fragmentation and loss of synchronous composability, and analyzes existing solutions including mesh and hub-based approaches, highlighting their limitations concerning credible neutrality and economic security. We present rebased rollups as a practical solution, detailing their architecture, security trade-offs, and mechanisms such as preconfirmations and dynamic attestation tracking.
We conclude by outlining how rebased rollups horizontally scale economic security and transaction throughput, providing Ethereum-aligned synchronous composability with latency comparable to centralized sequencers, ultimately balancing decentralization, neutrality, performance, and cost-effectiveness for the broader Ethereum ecosystem.
Alejandro Ranchal-Pedrosa is a Senior Protocol Researcher at scroll.io, working on improving the security, scalability and cost of the scroll ZK-Rollup for Ethereum. Prior to Scroll, Alejandro worked as a Protocol Researcher at Protocol Labs, primarily focused on providing faster finality for Filecoin through a novel architecture for longest-chain blockchains and a novel BFT consensus protocol designed for fast finality in open systems (F3 and GossiPBFT). At Protocol Labs, Alejandro also worked on providing crypto economic guarantees to Filecoin’s user-spawned subnets that interoperate in the Filecoin ecosystem (IPC), and on designing and implementing a framework for SMR systems (Mir). Before Protocol Labs, Alejandro worked at CEA Paris proposing protocols for scaling payment channels networks, as well as at IMT Paris and UAB Barcelona, where he found two critical attacks common to the Lightning Network and all its implementations. During his PhD at the University of Sydney, he worked on scaling Blockchains through subnets, increasing Blockchains' security through novel faults and game theoretical models, and enhancing Blockchains' decentralization via committee sortition proposing novel random beacon protocols, under the supervision of Vincent Gramoli.