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Ethereum 2026 Upgrades: How PeerDAS and zkEVMs Finally Cracked the Blockchain Trilemma

· 9 min read
Dora Noda
Dora Noda
Software Engineer

"The trilemma has been solved—not on paper, but with live running code."

Those words from Vitalik Buterin on January 3, 2026, marked a watershed moment in blockchain history. For nearly a decade, the blockchain trilemma—the seemingly impossible task of achieving scalability, security, and decentralization simultaneously—had haunted every serious protocol designer. Now, with PeerDAS running on mainnet and zkEVMs reaching production-grade performance, Ethereum claims to have done what many thought impossible.

But what exactly changed? And what does this mean for developers, users, and the broader crypto ecosystem heading into 2026?

The Fusaka Upgrade: Ethereum's Biggest Leap Since the Merge​

On December 3, 2025, at slot 13,164,544 (21:49:11 UTC), Ethereum activated the Fusaka network upgrade—its second major code change of the year and arguably its most consequential since the Merge. The upgrade introduced PeerDAS (Peer Data Availability Sampling), a networking protocol that fundamentally transforms how Ethereum handles data.

Before Fusaka, every Ethereum node had to download and store all blob data—the temporary data packets that rollups use to post transaction batches to Layer 1. This requirement created a bottleneck: increasing data throughput meant demanding more from every node operator, threatening decentralization.

PeerDAS changes this equation entirely. Now, each node is responsible for only 1/8th of the total blob data, with the network using erasure coding to ensure any 50% of pieces can reconstruct the full dataset. Validators who previously downloaded 750 MB of blob data per day now need only about 112 MB—an 85% reduction in bandwidth requirements.

The immediate results speak for themselves:

  • Layer 2 transaction fees dropped 40-60% within the first month
  • Blob targets increased from 6 to 10 per block (with 21 coming in January 2026)
  • The L2 ecosystem can now theoretically handle 100,000+ TPS—exceeding Visa's average of 65,000

How PeerDAS Actually Works: Data Availability Without the Download​

The genius of PeerDAS lies in sampling. Instead of downloading everything, nodes verify that data exists by requesting random portions. Here's the technical breakdown:

Extended blob data is divided into 128 pieces called columns. Each regular node participates in at least 8 randomly chosen column subnets. Because the data was extended using erasure coding before distribution, receiving just 8 of 128 columns (about 12.5% of the data) is mathematically sufficient to prove the full data was made available.

Think of it like checking a jigsaw puzzle: you don't need to assemble every piece to verify the box isn't missing half of them. A carefully chosen sample tells you what you need to know.

This design achieves something remarkable: theoretical 8x scaling compared to the previous "everyone downloads everything" model, without increasing hardware requirements for node operators. Solo stakers running validator nodes from home can still participate—decentralization preserved.

The upgrade also includes EIP-7918, which ties blob base fees to L1 gas demand. This prevents fees from dropping to meaningless 1-wei levels, stabilizing validator rewards and reducing spam from rollups gaming the fee market.

zkEVMs: From Theory to "Production-Quality Performance"​

While PeerDAS handles data availability, the second half of Ethereum's trilemma solution involves zkEVMs—zero-knowledge Ethereum Virtual Machines that allow blocks to be validated using cryptographic proofs instead of re-execution.

The progress here has been staggering. In July 2025, the Ethereum Foundation published "Shipping an L1 zkEVM #1: Realtime Proving," formally introducing the roadmap for ZK-based validation. Nine months later, the ecosystem crushed its targets:

  • Proving latency: Dropped from 16 minutes to 16 seconds
  • Proving costs: Collapsed by 45x
  • Block coverage: 99% of all Ethereum blocks proven in under 10 seconds on target hardware

These numbers represent a fundamental shift. The main participating teams—SP1 Turbo (Succinct Labs), Pico (Brevis), RISC Zero, ZisK, Airbender (zkSync), OpenVM (Axiom), and Jolt (a16z)—have collectively demonstrated that real-time proving isn't just possible, it's practical.

The ultimate goal is what Vitalik calls "Validate instead of Execute." Validators would verify a small cryptographic proof rather than re-computing every transaction. This decouples security from computational intensity, allowing the network to process far more throughput while maintaining (or even improving) its security guarantees.

The zkEVM Type System: Understanding the Trade-offs​

Not all zkEVMs are created equal. Vitalik's 2022 classification system remains essential for understanding the design space:

Type 1 (Full Ethereum Equivalence): These zkEVMs are identical to Ethereum at the bytecode level—the "holy grail" but also the slowest to generate proofs. Existing apps and tools work out of the box with zero modifications. Taiko exemplifies this approach.

Type 2 (Full EVM Compatibility): These prioritize EVM equivalence while making minor modifications to improve proof generation. They might replace Ethereum's Keccak-based Merkle Patricia tree with ZK-friendlier hash functions like Poseidon. Scroll and Linea take this path.

Type 2.5 (Semi-Compatibility): Slight modifications to gas costs and precompiles in exchange for meaningful performance gains. Polygon zkEVM and Kakarot operate here.

Type 3 (Partial Compatibility): Greater departures from strict EVM compatibility to enable easier development and proof generation. Most Ethereum applications work, but some require rewrites.

The December 2025 announcement from the Ethereum Foundation set clear milestones: teams must achieve 128-bit provable security by year-end 2026. Security, not just performance, is now the gating factor for wider zkEVM adoption.

The 2026-2030 Roadmap: What Comes Next​

Buterin's January 2026 post outlined a detailed roadmap for Ethereum's continued evolution:

2026 Milestones:

  • Large gas limit increases independent of zkEVMs, enabled by BALs (Block Auction Limits) and ePBS (enshrined Proposer-Builder Separation)
  • First opportunities to run a zkEVM node
  • BPO2 fork (January 2026) raising gas limit from 60M to 80M
  • Max blobs reaching 21 per block

2026-2028 Phase:

  • Gas repricings to better reflect actual computational costs
  • Changes to state structure
  • Execution payload migration into blobs
  • Other adjustments to make higher gas limits safe

2027-2030 Phase:

  • zkEVMs become the primary validation method
  • Initial zkEVM operation alongside standard EVM in Layer 2 rollups
  • Potential evolution to zkEVMs as default validators for Layer 1 blocks
  • Full backward compatibility for all existing applications maintained

The "Lean Ethereum Plan" spanning 2026-2035 aims for quantum resistance and sustained 10,000+ TPS at the base layer, with Layer 2s pushing aggregate throughput even higher.

What This Means for Developers and Users​

For developers building on Ethereum, the implications are significant:

Lower costs: With L2 fees dropping 40-60% post-Fusaka and potentially 90%+ reductions as blob counts scale in 2026, previously uneconomical applications become viable. Micro-transactions, frequent state updates, and complex smart contract interactions all benefit.

Preserved tooling: The focus on EVM equivalence means existing development stacks remain relevant. Solidity, Hardhat, Foundry—the tools developers know continue to work as zkEVM adoption grows.

New verification models: As zkEVMs mature, applications can leverage cryptographic proofs for previously impossible use cases. Trustless bridges, verifiable off-chain computation, and privacy-preserving logic all become more practical.

For users, the benefits are more immediate:

Faster finality: ZK proofs can provide cryptographic finality without waiting for challenge periods, reducing settlement times for cross-chain operations.

Lower fees: The combination of data availability scaling and execution efficiency improvements flows directly to end users through reduced transaction costs.

Same security model: Importantly, none of these improvements require trusting new parties. The security derives from mathematics—cryptographic proofs and erasure coding guarantees—not from new validator sets or committee assumptions.

The Remaining Challenges​

Despite the triumphant framing, significant work remains. Buterin himself acknowledged that "safety is what remains" for zkEVMs. The Ethereum Foundation's security-focused 2026 roadmap reflects this reality.

Proving security: Achieving 128-bit provable security across all zkEVM implementations requires rigorous cryptographic auditing and formal verification. The complexity of these systems creates substantial attack surface.

Prover centralization: Currently, ZK proving is computationally intensive enough that only specialized entities can economically produce proofs. While decentralized prover networks are in development, premature zkEVM rollout risks creating new centralization vectors.

State bloat: Even with execution efficiency improvements, Ethereum's state continues to grow. The roadmap includes state expiry and Verkle Trees (planned for the Hegota upgrade in late 2026), but these are complex changes that could disrupt existing applications.

Coordination complexity: The number of moving pieces—PeerDAS, zkEVMs, BALs, ePBS, blob parameter adjustments, gas repricings—creates coordination challenges. Each upgrade must be sequenced carefully to avoid regressions.

Conclusion: A New Era for Ethereum​

The blockchain trilemma defined a decade of protocol design. It shaped Bitcoin's conservative approach, justified countless "Ethereum killers," and drove billions in alternative L1 investment. Now, with live code running on mainnet, Ethereum claims to have navigated the trilemma through clever engineering rather than fundamental compromise.

The combination of PeerDAS and zkEVMs represents something genuinely new: a system where nodes can verify more data while downloading less, where execution can be proven rather than re-computed, and where scalability improvements strengthen rather than weaken decentralization.

Will this hold up under the stress of real-world adoption? Will zkEVM security prove robust enough for L1 integration? Will the coordination challenges of the 2026-2030 roadmap be met? These questions remain open.

But for the first time, the path from current Ethereum to a truly scalable, secure, decentralized network runs through deployed technology rather than theoretical whitepapers. That distinction—live code versus academic papers—may prove to be the most significant shift in blockchain history since the invention of proof-of-stake.

The trilemma, it seems, has met its match.

References​

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