1. What is Fusaka? Its position on the timeline.
Fusaka is a major hard fork upgrade for Ethereum in 2025 (after Pectra).
Mainnet activation time: 2025-12-03 21:49:11 UTC, following multiple rounds of rehearsals on various testnets.
The name is derived from Fulu (the star name of the consensus layer) + Osaka (the city that hosted Devcon), indicating that this upgrade modifies both the consensus layer and the execution layer.
Official positioning: A security-first upgrade centered on 'data availability + scalability' that occurs after Dencun/EIP-4844 and before parallel execution (Glamsterdam).
II. Core goal: Who's pain points are to be solved?
The more than ten EIPs included in Fusaka can be roughly divided into four categories:
Data availability & expansion
PeerDAS (EIP-7594)
Blob parameter adjustment, fee scheduling, etc.
Gas & execution rules
Increase block Gas limit
Limit single transaction Gas
Limit block size and prevent DoS attacks
Cryptography & user experience
secp256r1 precompiled (paving the way for Passkey wallets)
CLZ instructions, MODEXP pricing, etc.
Validators & historical data management
Deterministic Proposer Lookahead
Historical data expiration / simplification (History Expiry)
In summary:
Make L2 cheaper, L1 more resilient, wallets easier to use, and nodes lighter.
III. The most significant: EIP-7594 PeerDAS - allowing L2 to truly take off
1. Current issues: 4844's 'semi-finished product expansion'
Dencun / EIP-4844 introduced Blobs, separating L2 data from ordinary transactions; however, when verifying data availability, nodes still need to download the complete Blob. As the number of Blobs increases:
Node bandwidth and storage pressure rise sharply;
The protocol has to conservatively limit the number of Blobs, discounting the expansion effect.
2. The core idea of PeerDAS
PeerDAS = Peer Data Availability Sampling, core logic:
Split large Blobs into many 'small fragments' using erasure coding;
Nodes no longer download entire block data but sample small fragments randomly from multiple nodes;
Sampling results meet certain conditions, allowing for high confidence that the entire block of data is available;
Each node only bears a small portion of the global data storage and bandwidth.
Direct effect:
The burden on single nodes has significantly decreased, allowing for a safe increase in the number of Blobs per block;
Equivalent to providing L2 with greater DA bandwidth, theoretically increasing TPS by an order of magnitude;
Seen as a key step towards transitioning to true Danksharding.
3. The impact on all parties
Rollup projects: need to update data proof logic, be compatible with new sampling schemes, otherwise they may not function properly after the upgrade.
Nodes / infrastructure: need to support new sampling protocols and caching mechanisms.
This can be understood as:
This upgrade is a real KPI for the L2 team. Those who act slowly will not see their Gas drop, making it easier for users to flow to faster-moving competitors.
IV. Gas & execution: larger blocks, safer limits
1. Block Gas limit raised to 60M
Related EIPs will raise the default block Gas limit to about 60,000,000, bringing:
Single blocks can accommodate more Rollup batch transactions and complex DeFi transactions;
Overall throughput capacity further enhanced.
Supporting protective measures:
Single transaction Gas limit: avoid extreme situations where 'a single transaction consumes the entire block Gas.'
Block size limit (about 10 MiB): limits block size after RLP encoding, reduces network propagation delay, and lowers reorganization probability.
This set of changes can be likened to:
“Add more lanes to the highway while setting a maximum vehicle size to prevent a giant truck from blocking the road.”
2. MODEXP, CLZ, etc.: repricing contracts that are 'mathematically heavy'
Adjusting the Gas limit and fees for the MODEXP precompiled contract, fixing previous underestimations of the cost of large number modular exponentiation, alleviating potential DoS attack space.
New CLZ (Count Leading Zeros) instruction facilitates the implementation of logarithmic, bitwise operations, random numbers, etc., making some computational contracts more efficient and gas-saving.
The impact is roughly:
Certain ZK and cryptographic-related contracts may face rising costs due to more realistic MODEXP pricing;
Ordinary DeFi and algorithm contracts benefit from commands like CLZ, resulting in a slight decrease in Gas.
V. Cryptography & wallet experience: Passkey wallets brought by EIP-7951
1. secp256r1 precompiled: connecting to mobile native security modules
New native support for secp256r1 (P-256 Elliptic Curve).
This curve is very common in WebAuthn, FIDO2, Apple/Google Passkey, and enterprise HSMs.
Previously:
Ethereum only natively supports secp256k1;
To use Passkey, one often has to either verify signatures off-chain or implement them on-chain using very expensive Solidity.
Now:
Wallets can directly utilize the hardware security modules of mobile phones or browsers for signature verification.
Opened a feasible and cost-effective path for Passkey wallets without mnemonics.
2. The significance for users and applications
New users do not need to understand private keys and mnemonics; they can use wallets by operating similarly to logging into an Apple ID.
Multi-end synchronization and multi-person management (multi-factor authentication) become easier to achieve;
Improving friendliness towards compliant institutions and enterprise applications, conducive to more traditional users entering Web3.
VI. Validators & nodes: more predictable and lightweight
1. Deterministic Proposer Lookahead
The Beacon chain can learn the future block proposer order in advance over a longer time window.
Benefits include: more efficient coordination of MEV relays and PBS (Proposer-Builder Separation);
Rollups can provide more stable pre-confirmations;
Reduce the probability of on-chain reorganization and improve network stability.
2. Historical data expiration (History Expiry)
Introducing 'expiration' and simplification mechanisms for on-chain historical data: ordinary full nodes can prune older historical data to reduce disk occupation;
Services requiring complete history are handled by archive nodes.
The goal is to ensure that years later, ordinary individuals can still run full nodes without being completely monopolized by data centers.
VII. The impact of ETH price and narrative
1. Medium to long term: evolving towards 'high-performance settlement & data layer'
Fusaka will further push Ethereum towards this positioning:
L1: responsible for security, consensus, settlement, and data availability;
L2: undertaking a large amount of TPS and specific business scenarios through the greater DA bandwidth provided by PeerDAS;
Passkey and other features improve user entry experience, laying the foundation for the next wave of user growth and application landing.
The medium to long-term narrative can be summarized as:
“ETH is transitioning from a 'slow but secure' main chain to a global settlement and data layer that balances security and high throughput.”
2. Short-term: realization of benefits and expectation differences
Before and after the upgrade, the market often experiences fluctuations of 'buy the expectation, sell the facts': some funds have already ambushed before the upgrade.
There may be a spike and subsequent drop on the upgrade day or in the short term.
What is truly more important is whether the fees of L2 continue to decrease after the upgrade;
Whether the ecosystem's activity, TVL, and user count have significantly increased;
Whether developers quickly follow up on new features and launch new applications and gameplay.
3. Risks and uncertainties
High technical complexity: changes like PeerDAS, History Expiry, etc., if not implemented correctly, may lead to hidden bugs.
Compatibility issues: some Rollups or contracts may encounter anomalies after the upgrade if not adapted in time.
Economic parameters still need tuning: Blob fees, Gas pricing, etc., may be adjusted again in the future.
In summary:
Fusaka is another 'infrastructure leap' for Ethereum after Dencun, with the core aim of allowing L2 to truly take off, making nodes lightweight and sustainable, and bringing user experience closer to Web2 while laying a solid foundation for future parallel execution and larger-scale expansion.
