Why Rollups Need a DA Layer and How EIP-4844 Boosts Ethereum's Capabilities
The Scalability Trilemma and Rollups
For years, Ethereum has grappled with the scalability trilemma—balancing decentralization, security, and scalability. The community’s solution? A rollup-centric approach. Rollups offload execution from Layer 1 (L1) to cheaper environments while ensuring correctness through validity proofs (ZK) or fraud proofs (OP). But here’s the catch: rollups need more than just execution integrity; they need data availability (DA).
What’s a DA Layer, Anyway?
A DA layer guarantees that data is publicly available long enough for interested parties to retrieve it. Without it, rollups can’t ensure state recoverability, undermining user trust. Currently, most rollups use Ethereum itself as their DA layer by embedding data in calldata—a costly method that EIP-4844 aims to optimize.
Enter EIP-4844: Proto-Danksharding
EIP-4844 introduces blob-carrying transactions, a new format designed solely for DA. Unlike calldata, blobs are cheaper because they’re inaccessible to smart contracts—only their commitments are stored on-chain. This reduces costs for rollups while maintaining security.
Key Features of EIP-4844:
- Separate Fee Market: Blob gas prices are independent of L1 gas fees, shielding rollups from volatility.
- Temporary Storage: Blobs persist for ~18 days—long enough for verification but not forever.
- KZG Commitments: Ensures data integrity without bloating Ethereum’s state.
Scroll’s Approach to DA
As a ZK-Rollup, Scroll relies on Ethereum for DA. Post-EIP-4844, it will transition from calldata to blobs, slashing costs while preserving security. The PI circuit—a subcomponent of Scroll’s zkEVM—validates blob consistency using cryptographic proofs.
The Road Ahead: Danksharding
EIP-4844 is just the beginning. Full Danksharding will introduce data availability sampling (DAS), enabling nodes to verify large blocks efficiently. Until then, rollups must balance cost and security—whether via blobs or alternative DA layers.
Thoughts? How do you see EIP-4844 shaping Ethereum’s future? Drop your take below.
