Ethereum's Fusaka Upgrade 2025: L1 Scaling and Enhanced User Experience

Key Objectives of the Fusaka Upgrade

The Fusaka upgrade, inspired by the names of the execution layer upgrade Osaka and the consensus layer version Fula Star, scheduled for activation on December 3, 2025, at 21:49 UTC, aims to revolutionize Ethereum. This upgrade incorporates 12 Ethereum Improvement Proposals (EIPs) addressing data availability, gas/block capacity, security optimizations, signature compatibility, and transaction fee structure. Fusaka represents a systematic upgrade aimed at scaling Layer 1 (L1), reducing Layer 2 (L2) costs, minimizing node costs, and enhancing user experience.

Objective 1: Enhance Ethereum Performance

Fusaka's primary objective focuses on significantly boosting Ethereum's underlying performance and scalability. Key components include:

• Data availability scaling
• Reduced node burden
• More flexible blobs
• Improved execution efficiency
• More effective and secure consensus mechanisms

In short, Fusaka aims to further elevate Ethereum's performance.

Objective 2: Improve User Experience

Fusaka seeks to improve user experience and foster the next generation of wallets and account abstraction. Key aspects include:

• Block pre-confirmation
• P-256 (device-native signature) support
• Support for mnemonic-less wallets
• A more modern account system

Ethereum is evolving towards a mainstream network software experience.

Five Key Changes in Fusaka

1. PeerDAS: Alleviating Node Data Storage Burden

PeerDAS is a core new addition to the Fusaka upgrade. Currently, Layer 2 (L2) nodes use blobs (a temporary data type) to post data to Ethereum. Before the Fusaka upgrade, every full node had to store every blob to ensure data existence. As blob throughput increases, downloading all this data would become extremely resource-intensive, making it difficult for nodes to handle. PeerDAS is a solution employing data availability sampling, enabling each node to store only a portion of the data blocks rather than having to store them all. To ensure data availability, any portion of data can be reconstructed through 50% of the existing data, reducing the probability of faulty or missing data to a cryptographically negligible level. This is achieved by applying Reed-Solomon-style erasure coding to blob data. PeerDAS enables blob scaling while keeping node hardware and bandwidth requirements within acceptable ranges.

2. On-Demand Flexible Increase in Blob Count

To coordinate consistent upgrades of all nodes, clients, and validator software, it's essential to progress incrementally. To more quickly address the evolving needs of Layer 2 (L2) data blocks, a forking mechanism that relies solely on data block parameters (blob-parameter-only forks) has been introduced. With Fusaka, the number of blobs can be increased at a sustainable pace without the need for major network upgrades.

3. Support for Historical Record Expiry: Reducing Node Costs

To reduce the disk space required for node operators as Ethereum continues to grow, clients are required to start supporting the function of partial historical record expiry. In fact, clients can implement this feature at any time, but it is explicitly included in the to-do list with this upgrade.

4. Achieving Block Pre-Confirmation Early

With the aid of EIP7917, the Beacon Chain will be able to sense the block proposers for the next epoch. Knowing which validators will be proposing future blocks in advance can enable pre-confirmation. Reaching a commitment with the upcoming proposed block's creator guarantees the inclusion of user transactions in that block without waiting for the actual block's generation. This feature benefits client implementation and network security as it prevents validators from manipulating proposer scheduling. Additionally, the forward-looking function reduces implementation complexity.

5. Native P-256 Signature: Ethereum Directly Aligns with 5 Billion Mobile Devices

Introducing a built-in, passkey-like secp256r1 (P-256) signature checker at a fixed address. This is the native signature algorithm used by systems such as Apple/Android/FIDO2/WebAuthn. For users, this upgrade unlocks device-native signature and passkey functionality. Wallets can directly access Apple Secure Enclave, Android KeyStore, Hardware Security Modules (HSM), and FIDO2/WebAuthn – without the need for a mnemonic, a smoother registration process, and a multi-factor authentication experience comparable to modern apps. This will bring a better user experience, more convenient account recovery methods, and an account abstraction pattern that aligns with the existing functions of billions of devices. For developers, it accepts a 160-byte input and returns a 32-byte output, making it easy to port existing libraries and Layer 2 (L2) contracts. The underlying layer includes pointers to infinity and modulus comparison checks to eliminate tricky edge cases without breaking valid callers.

Long-Term Impacts of the Fusaka Upgrade

1. Impact on L2: Scaling enters the second curve. Through PeerDAS and on-demand increase in blob count, and a fairer data fee mechanism, data availability bottlenecks are resolved, and Fusaka accelerates the decline in L2 costs.
2. Impact on Nodes: Continued reduction in operating costs. Lower storage requirements and shorter synchronization times reduce operating costs. In the long run, it ensures the sustainable participation of weak hardware nodes, thereby ensuring the continued decentralization of the network.
3. Impact on DApps: More complex on-chain logic becomes possible. More efficient mathematical opcodes and more predictable block proposal timelines could drive high-performance AMMs, more complex derivative protocols, and fully on-chain applications, etc.
4. Impact on General Users: Blockchain can finally be used like Web2. P-256 signature means - no mnemonic, mobile phone is a wallet, more convenient login, easier recovery, multi-factor authentication is naturally integrated. This is a revolutionary change in user experience and one of the necessary conditions for upgrading 1 billion users.

Summary

Fusaka is a critical step towards DankSharding and large-scale user adoption. Dencun opened the era of Blobs (Proto-DankSharding), Pectra optimized execution and the impact of EIP-4844, while Fusaka makes Ethereum take a crucial step towards "permanent scaling + mobile first".

TLDR: This upgrade will include 12 EIPs, including:

• EIP-7594: Employs PeerDAS to reduce the data storage burden on nodes.
• EIP-7642: Introduces historical record expiry functionality to reduce the disk space required for nodes.
• EIP-7823: Sets a cap on MODEXP to prevent consensus vulnerabilities.
• EIP-7825: Introduces a transaction gas cap to prevent a single transaction from consuming most of the block space.
• EIP-7883: Increases the gas cost of ModExp encryption precompile to prevent potential denial-of-service attacks due to underpricing.
• EIP-7892: Supports on-demand flexible increase in blob count to meet the ever-changing needs of Layer2.
• EIP-7917: Achieves block pre-confirmation to improve the predictability of transaction order.
• EIP-7918: Introduces a base blob fee linked to execution costs to address data block fee market problems.
• EIP-7934: Limits the RLP execution block to a maximum of 10MB to prevent network instability and denial-of-service attacks.
• EIP-7935: Raises the default gas limit to 60M to expand L1 execution capacity.
• EIP-7939: Adds CLZ opcode to make on-chain calculations more efficient.
• EIP-7951: Adds precompiled secp256r1 curve support to improve user experience.