On December 3, 2023, the Ethereum blockchain will undergo the Fusaka upgrade, a significant technical enhancement aimed at augmenting rollup throughput, optimizing gas markets, and integrating native support for passkey-style signatures. This upgrade is part of Ethereum’s ongoing evolution and commitment to improving network efficiency and user experience.
The Fusaka fork introduces several pivotal modifications, including PeerDAS (Data Availability Sampling), which enhances data verification processes, doubles the default block gas limit, and lays the groundwork for subsequent blob-only parameter expansions anticipated later this month and into January.
Significantly, the nomenclature of ‘Fusaka’ is derived from the star Fulu, meaning ‘auxiliary road,’ in conjunction with Osaka, a city characterized by its slopes and hills. This naming convention continues Ethereum’s tradition of associating celestial bodies with terrestrial locations.
Editor’s Note: The term ‘sloping side road’ serves as a playful interpretation of the Fulu + Osaka amalgamation rather than an official translation.
Data Availability Enhancement: A New Scaling Paradigm
The cornerstone of the Fusaka upgrade is the implementation of PeerDAS, delineated in Ethereum Improvement Proposal (EIP) 7694. This groundbreaking protocol permits nodes to ascertain the existence of blob data through small-sample verification rather than necessitating the complete download of entire blobs. This innovation effectively mitigates a critical scaling bottleneck that was initially introduced by EIP-4844, offering a trajectory to potentially enhance blob throughput by an order of magnitude over time.
The augmentation in blob capacity will yield direct economic benefits by significantly lowering layer-two transaction fees. Rollups will be able to compress user transactions into blobs that are subsequently posted to Ethereum’s base layer.
Additionally, the Fusaka upgrade raises the default gas limit per block to 60 million gas, a substantial increase from the previous threshold of 30 million established post-Merge. This adjustment effectively doubles the layer-one (L1) block gas budget, thereby providing enhanced capacity for both standard transactions and blob processing.
To further bolster this initiative, two forthcoming forks—termed Blob Parameter Only (BPO1) and BPO2—are scheduled for December 9 and January 7 respectively. These forks will facilitate adjustments to blob parameters without necessitating any additional code changes, thereby enhancing overall capacity.
Reconfiguration of the Blob Fee Market
EIP-7918 introduces a novel mechanism linking the minimum base fee for blobs directly to execution gas costs. This strategic modification prevents the market pricing for blobs from plummeting towards zero while layer-one gas prices remain elevated. Such an alignment ensures that the data-availability market remains economically viable amid fluctuating usage patterns.
Previously observed discrepancies between blob fees and execution costs led to stark divergences that fostered arbitrage opportunities, ultimately distorting rollup economics. In conjunction with this fee reconfiguration, several related EIPs—namely 7823, 7825, 7883, and 7934—have been proposed to enhance network security and operational integrity. These proposals include:
- Imposition of caps on ModExp precompile input sizes;
- Augmentation of gas costs associated with ModExp;
- Establishment of transaction gas limit ceilings;
- Enforcement of RLP block size limitations.
Together, these constraints serve to diminish vulnerability to denial-of-service attacks while rendering worst-case client workloads more predictable.
Advancements in Developer Tools and Cryptographic Functionality
EIP-7939 introduces a count-leading-zeros opcode that simplifies on-chain operations involving bit manipulation and integer logarithms, thus lowering computational costs associated with these tasks. This addition is particularly advantageous for decentralized finance (DeFi) protocols and cryptographic contracts reliant on efficient bitwise operations.
An associated enhancement specified in EIP-7917 provides validators with a deterministic proposer lookahead schedule, affording them clarity regarding block proposal timelines. This transparency allows miners and staking operators to coordinate their activities more securely and efficiently while minimizing uncertainty in block production workflows.
Moreover, EIP-7951 establishes a native precompile for the secp256r1 curve—the cryptographic standard employed by platforms such as Apple Secure Enclave, Android Keystore, and WebAuthn. This innovation enables wallets and smart account architectures to validate passkey-style signatures natively on Ethereum. Consequently, it facilitates authentication flows utilizing biometric technologies like FaceID and TouchID without requiring custom bridges or circuits. This precompile effectively eliminates a significant friction point for applications targeting consumer-facing implementations.
Execution Strategy: Immediate Deployment and Phased Rollout
The Fusaka upgrade will be activated at a designated block height on December 3rd. Following this initial deployment, subsequent adjustments to blob parameters will occur six days later with BPO1; BPO2 will finalize this phase of capacity expansion on January 7th. The strategic phased rollout allows node operators and rollup teams to meticulously monitor blob utilization patterns alongside client performance metrics prior to implementing subsequent parameter enhancements.
Importantly, this upgrade does not introduce any alterations to consensus-layer mechanisms related to staking or validator incentives; all modifications are strictly confined to execution-layer throughput improvements, gas mechanics optimization, and enhancements in developer primitives.
Validators operating updated clients will be able to process new opcodes and blob logic seamlessly without necessitating changes to their existing staking frameworks. The Fusaka upgrade marks Ethereum’s most throughput-focused enhancement since EIP-4844 introduced blobs earlier in March 2024. By effectively doubling block gas capacity, scaling data availability sampling methodologies, and embedding cryptographic hooks for mainstream authentication hardware usage, Fusaka strategically positions Ethereum to accommodate increased rollup activity without corresponding fee escalations while concurrently equipping developers with novel primitives for enhanced on-chain computations and user onboarding processes.
