Why Proof-of-Inclusion is Critical for the Next Generation of Verifiable Data

Proof-of-Inclusion (PoI) is the atomic unit of trust for decentralized systems. It is a cryptographic proof that specific data exists within a larger, agreed-upon dataset, like a blockchain or a data availability layer. This moves verification from checking the entire chain to validating a single, succinct proof.

Current blockchains only prove finality, not content. L2s like Arbitrum and Optimism prove a batch of transactions was finalized on Ethereum, but they do not natively prove that your specific transaction is inside that batch. This creates a verification gap for cross-chain applications and data consumers.

The next generation of interoperability depends on PoI. Protocols like LayerZero and Axelar rely on off-chain attestations. A standardized PoI primitive, akin to what Celestia's Blobstream provides for rollups, would allow these systems to move from trusted relayers to cryptographically verifiable data proofs.

Evidence: Without PoI, intent-based systems like UniswapX and CowSwap require centralized sequencers to resolve cross-chain trades. A universal PoI standard would decentralize this process, enabling verifiable inclusion of orders and settlements across any chain.

Proof-of-Inclusion (PoI) is the atomic unit of verifiability. It cryptographically proves a specific piece of data exists within a larger dataset without revealing the whole set, moving beyond simple data availability to actionable data verification.

Current systems like Celestia or EigenDA provide data availability, not verification. They guarantee data is published, but applications must still download and recompute entire blocks to verify specific transactions, creating a scalability bottleneck for light clients and cross-chain protocols.

PoI enables stateless verification for protocols like Uniswap and Aave. A light client can verify a single user's swap or liquidation event with a Merkle proof, eliminating the need to sync the entire chain state, which is the core innovation behind intent-based architectures.

The metric is verification overhead. Without PoI, a zkRollup's proof verification on Ethereum costs ~500k gas; with PoI, a light client verifies a single inclusion in sub-100k gas, enabling verifiable data feeds for oracles like Chainlink and cross-chain messaging like LayerZero.

Proof-of-inclusion is non-negotiable. Modular architectures like Celestia and EigenDA separate execution from data availability, creating a trust gap between where data is stored and where it is used. Rollups on Arbitrum or Optimism must prove their transaction data was published to the base layer.

The alternative is re-centralization. Without cryptographic proofs, users and bridges like LayerZero and Across must trust operator honesty. This recreates the custodial risk that decentralized systems were built to eliminate, making data availability a meaningless promise.

Verifiable data enables new primitives. Proofs allow protocols like UniswapX to execute intents across chains with guaranteed settlement. They are the foundation for shared sequencers, like those proposed by Espresso, to prove censorship resistance.

Evidence: The Ethereum Dencun upgrade's proto-danksharding (EIP-4844) reduces costs but increases the attack surface for data withholding, making proofs essential for L2s like Base and zkSync to maintain security guarantees.

Proof-of-inclusion is the bottleneck. A blockchain's state is a function of its data. Without a cheap way to prove data exists, you cannot rebuild state or verify fraud proofs. This is the core challenge for modular architectures like Celestia and EigenDA.

Merkle proofs are the incumbent standard. They provide cryptographic proof that a transaction is in a block. Their simplicity powers light clients and bridges like Across. The scaling limitation is bandwidth; proofs grow logarithmically with data size, creating overhead for high-throughput chains.

KZG commitments are the polynomial alternative. A single, constant-sized KZG commitment can prove any piece of data within a larger blob. This eliminates the bandwidth problem, enabling efficient validity proofs for voluminous data in Ethereum's EIP-4844 blobs.

The trade-off is trust versus complexity. Merkle trees require no trusted setup but have larger proofs. KZG commitments need a one-time trusted ceremony but offer optimal proof size. The choice dictates the cost structure for L2s like Arbitrum or Optimism posting data.

The endgame is universal verification. A user's device must verify data from any chain. Projects like Avail and Near's Nightshade are building this infrastructure. Without it, data availability layers become trusted data providers, negating their cryptographic value.

Settlement is the ultimate backstop. Dedicated DA layers create a fragmented security model where finality depends on a separate, weaker chain. The L1 settlement layer already provides the strongest, most expensive-to-attack data availability guarantee. Replicating this off-chain introduces unnecessary trust and complexity.

Proof-of-Inclusion is the universal primitive. The critical innovation is not a new DA layer, but a cryptographic proof that data is available somewhere verifiable. This proof can be posted to any secure chain, like Ethereum or Bitcoin, making the location of the raw data a secondary concern. Projects like Celestia and EigenDA are solutions to a problem that Proof-of-Inclusion redefines.

The cost argument is a red herring. Proponents cite cheaper blob storage, but this ignores the systemic risk premium. A rollup using a dedicated DA layer trades Ethereum's security for marginal cost savings, creating a hidden liability. The failure of an external DA layer compromises all dependent rollups, a risk not priced into transaction fees.

Evidence: The Ethereum Dencun upgrade with EIP-4844 (blobs) reduced L2 costs by over 90% while keeping data secured by Ethereum validators. This demonstrates that scaling data availability on the settlement layer is the correct architectural path, not outsourcing it.

Proof-of-Inclusion primitives unlock data-centric architectures. Merkle trees and KZG commitments only prove state; they cannot prove that specific data was included in a transaction or block. This gap forces protocols like The Graph to index everything, creating massive redundancy and cost.

Verifiable data availability layers require inclusion proofs. A true DA layer like Celestia or EigenDA must prove a specific blob was published, not just that some data exists. Proof-of-Inclusion is the missing cryptographic link between data publication and its consumption by rollups like Arbitrum or zkSync.

Intent-based systems depend on inclusion proofs for trust. Protocols like UniswapX and CowSwap route orders off-chain. Proving order inclusion in a solver's bundle, not just final settlement, is critical for user trust and preventing MEV extraction.

Evidence: The Ethereum Danksharding roadmap explicitly separates data availability sampling (proving data is there) from data retrieval (fetching it). Proof-of-Inclusion is the cryptographic guarantee that makes sampling feasible at scale.