"Why, What, and How L2s Can Use Blob Transactions"

Keynote from Mikhail Kirov, researcher at LimeChain

🤔Why:
Ethereum is suffering from its own success - transaction fees are high. The current leading approach to fighting it is Rollups for scalability.

Rollups, however, are facing some issues with high operating costs and in particular costs for publishing their bundled transactions to the L1 for data availability

They want to keep their costs low and at the same time keep their systems secure and decentralized

Many popular rollups pay tens of millions of dollars every year with the total being well over 200 million dollars.

😱What:
Blob transactions, introduced through the concept of Protodunk Sharding or EIP-4844, play a crucial role in the Ethereum scaling roadmap. They are a new type of transaction that carries uninterpreted data payloads, termed as "blob sidecars".

These transactions are crucial for lowering data availability costs for rollups by providing a more efficient way to store large data payloads on the Ethereum network.

This solution leverages KZG commitments and a new precompile for KZG verification, secured by Ethereum's L1 consensus mechanism, to verify the data without processing it within the EVM.

🤓How:
Danksharding separates the current execution gas from the newly introduced Blob gas, effectively giving us new cheaper gas for Blobs, creating a potentially cheaper gas market for uninterpreted data intended for rollup use.

This new structure includes several technical enhancements such as versioned hashes for future compatibility, a new blob hash opcode, and a point precompile for validating the data.

For rollups and their users, this means significantly reduced transaction costs and data availability costs.

Rollups will need to undergo an upgrade to accommodate these changes, but this upgrade is designed to be a one-time requirement due to the common interfaces established for future Ethereum scaling efforts.