The Ethereum Foundation has issued an urgent advisory for blob transaction originators, including layer-2 networks, to update their software to generate cell proofs instead of blob proofs. This change is required by EIP-7594, also known as PeerDAS, which is set to activate with the upcoming Fusaka upgrade. The call follows recent disruptions on the Sepolia testnet, where some L2 deployments failed due to the new proof format.

According to the Ethereum Foundation, EIP-7594 alters the proof format from blob proofs to cell proofs, enabling data availability sampling to download only a specific part of a blob rather than the entire blob. While this improves efficiency, it can break user applications that send blob transactions. The foundation notes that already signed transactions remain valid, but they must recompute the cell proofs.

The foundation highlighted that some clients, most notably go-ethereum, will automatically convert blob proofs to cell proofs via RPC methods like eth_sendTransaction and eth_sendRawTransaction. However, this conversion takes about one second, adding overhead at the RPC level. Therefore, the foundation encourages blob originators to move to cell proofs directly to reduce this overhead.

Transactions already in the transaction pool at the time of the fork may be dropped by some implementations, while others will convert them. The foundation advises resending transactions with cell proofs shortly after the fork if they are not included by the chain. Some implementations allow distribution of blob proof transactions for a few minutes after the hard fork on the networking layer for stability.

Actionable Steps for Blob Originators

Blob transaction originators, such as L2s, should update their transaction sending code to create cell proofs. The foundation points out that all major client libraries expose functionality to generate these proofs via ComputeCellsAndKZGProofs(), available in all major languages. Usage examples are provided in the client libraries.

The Ethereum Foundation acknowledged that blob originators learned about this change late in the hard fork process, but emphasized that the testnet process is working well, catching issues long before they reach mainnet. They also committed to clearer communication on user-impacting changes via the Ethereum blog and increased community outreach.

The foundation encourages L2s and other entities dependent on the Ethereum roadmap to follow the All Core Devs (ACD) process and engage more directly with the community. They also recommend deploying contracts and test infrastructure on devnets before moving to testnets, and using the Ethereum package provided by Kurtosis to create local networks with the latest specifications.