Ethereum’s Fusaka Upgrade: Scaling Rollups And Unlocking Passkeys

Ethereum’s Fusaka hard fork goes live tonight, delivering a combined execution and consensus upgrade that is designed to scale the network’s capacity without breaking its decentralisation model.

The name “Fusaka” blends Osaka for the execution layer and Fulu for the consensus layer. Together they bundle roughly a dozen Ethereum Improvement Proposals (EIPs) that focus on three themes:

• Scaling data availability for rollups
• Tightening gas and fee mechanics for security
• Enabling passkey-style authentication directly on-chain

In other words, Fusaka is an infrastructure and scalability milestone rather than a user-facing feature drop. It is framed by core developers as a step forward in the rollup-centric roadmap, not as a catalyst aimed at forcing an immediate rally in the price of ETH.

PeerDAS: Letting Nodes Store One-Eighth Of Blob Data

The headline feature of Fusaka is Peer Data Availability Sampling, or PeerDAS.

Before Fusaka, every full node had to download and store all of the “blob” data that rollups post back to the Ethereum base layer. Blobs are the temporary data containers introduced to make it cheaper for rollups to publish large batches of transactions. As blob throughput grows, this full replication model becomes a bottleneck, pushing hardware requirements toward data-centre level machines.

PeerDAS changes that model. Instead of every node holding every blob, the network:

• Distributes blob data uniformly across nodes so that each full node is responsible for roughly one-eighth of the data.
• Uses sampling techniques so validators check random pieces of blob data from their peers, rather than re-downloading everything.
• Ensures that as long as a sufficient fraction of nodes participate honestly, missing or withheld data is detected with extremely high probability.

The practical effect is that the network can support up to an eightfold increase in blob data throughput for rollups while keeping node bandwidth and storage demands manageable. For Layer 2 systems, that translates into:

• More room per slot to post transaction batches
• Lower blob fees when demand is high
• A clearer path to scaling throughput without fragmenting liquidity across many base layers

Fusaka also includes “blob parameter only” follow-up forks that will gradually raise blob capacity, allowing client teams and rollups to observe how the network behaves under higher load before dialling it up further.

Gas Rules, Block Limits And Fee Dynamics

Fusaka is not only about blobs. It also reshapes how gas and fees work at the base layer.

Higher Block Gas Limit, Per-Transaction Cap

A key change is a higher effective block gas limit. Fusaka steers the network toward blocks with around 60 million gas, up from roughly 30–36 million previously. This gives more headroom for:

• Complex on-chain operations
• Call data and contract interactions
• Rollup-related activity that still relies on the execution layer

At the same time, a new per-transaction gas cap is introduced. This places a ceiling on how much gas any single transaction can consume. The combination is intentional:

• The higher block gas target increases total throughput for everyone.
• The per-transaction cap prevents one oversized transaction from monopolising an entire block or being used as an attack vector.

Repriced Heavy Operations And Blob Fee Guardrails

Fusaka also includes adjustments to the pricing of heavy cryptographic opcodes such as modular exponentiation. These changes:

• Bring the gas cost of certain big-integer and RSA-style operations closer to their real computational cost.
• Reduce the risk that underpriced operations can be abused to slow down block production.

On the data side, updated rules bind blob base fees more tightly to execution costs. This is intended to avoid scenarios where blob prices become unrealistically cheap while gas for normal transactions spikes, only for blob fees to “snap back” later. The goal is a more stable and predictable fee market for rollups.

Combined, these gas and fee changes are aimed at improving network efficiency and security while keeping room for rollups to grow.

Passkey-Style Authentication: secp256r1 On Ethereum

Another important piece of Fusaka lives at the cryptographic and user-experience layer.

Through EIP-7951, the upgrade adds a native precompile for the secp256r1 elliptic curve, the standard behind modern passkeys and WebAuthn. This is the curve used by hardware-backed secure enclaves such as Apple’s Secure Enclave and Android’s Keystore, as well as FIDO2 passkeys in most modern browsers.

Until now, Ethereum accounts have used a different curve, making it expensive or awkward to verify passkey signatures directly on-chain. Fusaka changes that by allowing smart contracts to:

• Verify secp256r1 signatures cheaply using a built-in precompile
• Accept signatures generated inside device secure enclaves
• Integrate biometric flows like FaceID or fingerprint unlock without complex workarounds

For users, this opens the door to wallets that feel more like familiar mobile banking apps:

• No seed phrases or separate hardware wallets for everyday balances
• Passwordless, biometric sign-in flows secured by the phone or laptop’s secure element
• Smart accounts that can mix passkeys, social recovery and spending limits

For developers, native secp256r1 support removes a major hurdle to building account-abstraction wallets and consumer-facing apps that rely on passkeys.

Who Benefits First: Rollups, Validators And Builders

Fusaka’s benefits will not arrive uniformly across the ecosystem. Different groups feel the changes in different ways.

Layer 2 Rollups

Rollups that post data to Ethereum in blobs are the most direct beneficiaries:

• More blob capacity and PeerDAS sampling mean cheaper data availability in busy periods.
• Expanded throughput allows rollups to support higher transaction volumes without bidding gas prices to extremes.
• Better blob fee mechanics make it easier to model and hedge costs over time.

In practice, users may see lower and more stable fees on major rollups as parameters are tuned over the coming weeks.

Validators And Node Operators

For validators and full-node operators, Fusaka is about balancing workload and decentralisation:

• PeerDAS reduces the amount of blob data any single node has to handle, lowering bandwidth pressure.
• Per-transaction gas caps and block-size limits reduce the risk of pathological blocks that are difficult to propagate.
• Higher overall block gas targets do increase per-slot work, but in a way that is designed to remain compatible with home-staking hardware.

The net effect should be a network that can do more work per block without forcing validators into ever more expensive infrastructure.

Developers And Application Teams

Builders gain new tools and primitives:

• Cheaper, more predictable data availability for rollups and data-heavy applications
• New precompiles and opcodes for cryptography, bit manipulation and signature schemes
• A clearer path to integrating passkey-style authentication into onboarding flows

For most users, these changes will show up indirectly as snappier apps, lower fees on rollups and the gradual appearance of wallets that use passkeys instead of seed phrases.

Market Impact: Infrastructure, Not A Guaranteed Pump

In the run-up to Fusaka, some analysts have speculated about whether the upgrade could trigger a rally similar to earlier forks. The consensus view among research desks, however, is that Fusaka is primarily an infrastructure move:

• Many of its core changes, such as PeerDAS and higher gas limits, have been known and tested for months.
• The upgrade improves Ethereum’s capacity to host rollups and applications, but it does not directly change ETH’s monetary policy or staking rules.
• Any price reaction is likely to depend more on broader market conditions, risk appetite and macro factors than on the technical details of the fork.

In that sense, Fusaka is another example of Ethereum prioritising long-term scalability and usability over short-term speculation.

Where Fusaka Sits In The Roadmap

Fusaka fits into the broader arc of Ethereum’s development.

Previous upgrades introduced proof-of-stake, enabled validator withdrawals and rolled out “blob” data for rollups. Fusaka builds on those steps by attacking the data availability bottleneck and preparing the ground for fuller forms of danksharding and parallel execution.

Looking ahead, the roadmap continues to focus on:

• Scaling via rollups and improved data availability
• Making nodes lighter and easier to run
• Enhancing account abstraction and user experience

Fusaka does not complete any of those goals, but it moves each of them forward in a tangible way.

Conclusion

Ethereum’s Fusaka upgrade is a technically dense but strategically important hard fork. By introducing PeerDAS, raising block gas limits and adding native support for passkey-style authentication, it aims to make the network more scalable, more secure and easier to use without sacrificing decentralisation.

For Layer 2 rollups, Fusaka promises cheaper data and more room to grow. For validators, it aims to keep home staking viable even as throughput increases. For developers and end users, it quietly lays the foundations for faster applications and wallet experiences that feel closer to mainstream finance.

What Fusaka does not guarantee is an immediate price spike. Instead, it should be understood as another step in Ethereum’s long-term strategy: turning the base layer into a robust, neutral settlement platform that can safely support a growing universe of rollups, applications and users.

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