Data Validity Proof

These Layer 2 solutions generate a zero-knowledge proof (a ZK-SNARK or ZK-STARK) that cryptographically attests to the validity of a batch of transactions. The proof is posted on the base layer (e.g., Ethereum), allowing the network to trust the state transition without re-executing all transactions.

• Core Mechanism: A prover generates a proof; a verifier contract on L1 checks it.
• Result: Enables high throughput and low fees while inheriting Ethereum's security for execution validity.

A scaling solution that uses validity proofs for execution but stores data off-chain. A Data Availability Committee (DAC) or cryptographic scheme like Volition ensures data is available when needed.

• Trade-off: Higher scalability than zk-Rollups, but introduces a data availability assumption.
• Use Case: Ideal for applications like gaming where extreme throughput is needed and users can opt-in to higher security models.

While not a validity proof in the cryptographic sense, this is a related dispute resolution mechanism. Transactions are assumed valid but can be challenged during a challenge period. A fraud proof is submitted to prove invalid state transitions.

• Contrast: Validity proofs provide cryptographic certainty; fraud proofs provide economic security via a game-theoretic challenge.
• Example: Arbitrum and Optimism originally used this model, though some are integrating validity proofs.

Celestia decouples execution from consensus and data availability. It uses erasure coding and Data Availability Sampling (DAS) to allow light nodes to probabilistically verify that all transaction data for a block is published and available.

• Key Innovation: Provides a robust data availability proof layer for modular blockchains.
• Impact: Rollups built on Celestia can post data cheaply and rely on its network for availability guarantees.

A data availability service built on Ethereum using restaking via EigenLayer. It doesn't generate validity proofs for execution but ensures data is available for Layer 2 rollups through a cryptoeconomically secured network of operators.

• Architecture: Uses dispersal and attestation protocols where operators attest to data availability.
• Purpose: Provides a high-throughput DA layer as an alternative to posting all data directly to Ethereum L1.

A cryptographic method allowing one party (the prover) to prove to another (the verifier) that a statement is true without revealing any information beyond the validity of the statement itself. Validity proofs (like zk-SNARKs and zk-STARKs) are a specific application used to prove the correctness of state transitions in a zk-rollup. Key properties include:

• Succinctness: The proof is small and fast to verify.
• Zero-Knowledge: The proof reveals no underlying transaction data.
• Soundness: A false statement cannot generate a valid proof.

The guarantee that all data necessary to reconstruct the state of a blockchain (like transaction batches in a rollup) is published and accessible to network participants. Data availability is a prerequisite for data validity proofs; a verifier cannot check a proof if the underlying data is hidden. Solutions include:

• Data Availability Committees (DACs): A trusted group attests to data availability.
• Data Availability Sampling (DAS): Light clients randomly sample small chunks to probabilistically guarantee the whole dataset is available.
• EigenDA, Celestia: Dedicated networks providing scalable data availability layers.

A cryptographic proof that demonstrates a state transition or published data is invalid. Used in optimistic rollups, it is the security mechanism that allows anyone to challenge and revert incorrect transactions during a dispute window (typically 7 days). The process involves:

• Assumption of Honesty: State updates are presumed valid.
• Challenge Period: A window where anyone can submit a fraud proof.
• Interactive Dispute Game: A multi-round challenge to pinpoint the exact faulty instruction. Contrasts with validity proofs, which proactively prove correctness.

A Layer 2 scaling solution that bundles (rolls up) hundreds of transactions off-chain and submits a validity proof (a ZKP) to the underlying Layer 1 (e.g., Ethereum) to verify their correctness. This proof, often a zk-SNARK or zk-STARK, ensures the new state root is valid without revealing transaction details. Key attributes:

• Finality: Funds can be withdrawn immediately after proof verification.
• Privacy: Inherits zero-knowledge properties, enabling confidential transactions.
• Cost Efficiency: Reduces L1 gas fees by compressing computation and data. Examples include zkSync Era, Starknet, and Polygon zkEVM.

A type of zero-knowledge proof that is succinct (small and fast to verify) and non-interactive (requires only one message from prover to verifier). zk-SNARKs are the most common cryptographic primitive for generating data validity proofs in production zk-rollups. Their architecture involves:

• Trusted Setup: A one-time ceremony to generate public parameters (a potential weakness).
• Circuit: The program (e.g., a rollup's state transition logic) compiled into an arithmetic circuit.
• Prover/Verifier: The prover generates the proof; the verifier checks it with minimal computation.

The process by which a blockchain updates its global state (account balances, contract storage) based on a set of valid transactions. A data validity proof is fundamentally a proof of correct state transition. It cryptographically attests that:

• The new state root (a cryptographic commitment to the entire state) is the correct result.
• All transactions in the batch were executed according to the protocol rules.
• The prior state root was valid. This allows verifiers to trust the new state without re-executing all transactions, enabling secure scaling.