How does the Cancun upgrade affect Layer2?
After over two months of testing on the Goerli, Sepolia, and Holesky testnet, the Ethereum Cancun Upgrade (Deneb) was eventually enabled on the Ethereum mainnet at 21:54 am on March 13, 2024, with a block height of 19,426,587.
Along with the Consensus update, the Cancun update aims to increase Ethereum’s scalability through several enhancements to the platform’s execution. This lowers Ethereum’s Layer2 Rollups solution’s transaction costs.
Reference：[History and Forks of Ethereum](https://ethereum.org/en/history/)
EIP-4844
EIP-4844, commonly referred to as Proto-Danksharding, is the primary component of the Cancun update. It presents a new transaction type that contains a blob; although the data carried in the blob cannot be accessible by EVM execution, its promised values may. All consensus nodes on Layer 1 can download all of the data conveyed in the blob transaction format, which is limited to the beacon chain (consensus layer). However, the data is automatically erased after a predetermined amount of time, which is currently set at 4096 epoches, or around 18 days.
With plans to handle up to 16 “blobs” in the future, each Ethereum L1 block can currently carry up to 6 “blobs,” which are 4096 field components of 32 bytes each. Each “blob” can support up to 128KB of data (0.125MB).
Rollup might be the only trust-free scaling option available for Ethereum in the near and medium term. For several months now, L1 transaction costs have been incredibly expensive. For many Ethereum users, rollups provide significant fee savings: ZK Rollups, with its improved data compression and ability to omit incorporating signatures, costs roughly 40–100x less than the Ethereum base layer, while Optimism and Arbitrum often offer about 3–8x lower fees than the base layer itself.
For many customers, even these prices are prohibitively high. Data sharding has always been the long-term answer to Rollup’s own recurring shortcomings; it would give Rollups access to an additional 16MB of dedicated data space per chain. Nevertheless, it will still take some time to fully implement and deploy data sharding.
By adopting the sharding-compatible transaction structure but avoiding the actual sharding of those transactions, EIP-4844 offers an equitable alternative. The maximum number of transactions allowed by the EIP is lower than with full data sharding; this translates to roughly 0.375MB of target data (3 blobs) and roughly 0.75MB of restricted data (6 blobs) each block.
Cited from：[EIPs/EIPS/eip-4844.md at master · ethereum/EIPs · GitHub](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-4844.md)
The sender balance is reduced by the data_fee that the blob uses, which is then destroyed prior to the transaction being completed. Even if the transaction fails, there is no reimbursement.
The data_fee consumed by the blob is calculated as follows:
The blob base fee is calculated in a similar way to EIP-1559, based on the supply and demand of BLOBs in the network. Specific use is exponential EIP — 1559 update algorithm, code is located in the go — ethereum/consensus/misc/eip4844 eip4844. Go/fakeExponential (). The blob base fee for block n is determined by the following formula:
p^{data}n = m \cdot exp(\frac{E{n-1}}{s})
§ m: MIN_BLOB_BASE_FEE
§ E_{n-1}: The cumulative amount of blob gas consumed by block n-1 so far exceeds the target, which is excess_blob_gas
§ s: BLOB_BASE_FEE_UPDATE_FRACTION, which limits the variation of the base fee of adjacent blocks
Set in another context, the blob base fee will grow exponentially when the blob gas consumed by a block consistently exceeds the target value (currently 3 blobs); conversely, the blob base fee will decrease exponentially until MIN_BLOB_BASE_FEE when the blob gas consumed by a block consistently falls below the target value. Adjacent blocks’ blob base fees have a change rate of 12.5%, which is comparable to the base charge in EIP-1559.
Effects on Layer 2
Layer 2(L2) is a catch-all term that describes a specific set of Ethereum scaling solutions. An L2 is a separate blockchain that extends Ethereum and inherits Ethereum’s security guarantees. Cited from: https://ethereum.org/en/layer-2/
Current Layer 2 solutions include Rollup (Optimistic Rollup and ZK-Rollup), state channels, sidechains, Plasma, Validium. The Cancun upgrade mainly affects the Rollup solution in Layer 2.
Rollup processes off-chain transactions in batches and publishes the results to Ethereum Layer 1 in order to scale Ethereum. In essence, there are two components to the Rollup: data and checking. After the rollup processes the data, a full transaction sequence of state changes is produced and published to Ethereum. To verify that the suggested state change is accurate, an honest participant (referred to as a prover) re-executes these transactions. The transaction data must be accessible for anyone to download and examine for an adequate amount of time to do the check. This implies that any dishonesty by rollup sequencer can be detected and challenged by the prover. It is not required to be accessible indefinitely, though.
So, how can Blob data be verified?
Rollup publishes the transactions they execute into the data blob and also publishes a “commitment” to the data. In simple terms, we construct a polynomial function out of the data, and then we can evaluate the function at various points, for example, if we define a very simple function f(x) = 2x -1, then we can evaluate the function x = 1, x = 2, x = 3 and give the result 1, 3, 5. prover ‘applies the same function to the data and evaluates it at the same points. If the original data changes, the function will not be the same, so each point will be evaluated differently. The actual promises and proofs are more complex and are encapsulated in cryptographic functions.
Instead of putting the Rollup block data into the L1 transaction calldata via calldata as before, rollup can put the data into the blob, which guarantees the data availability that Rollup needs. Rollup needs the data to be available once and for long enough to ensure that honest participants can access the data to build the Rollup state, rather than being available forever.
Reduced transaction costs
The main impact of the Cancun upgrade is the reduction of transaction costs for Rollup.
blob currently consumes 1 gas per byte, while calldata consumes 16gas per non-zero byte and 4gas per zero byte; blob also has a lower gas price, with calldata having a gwei class gas price and blob having a wei class gas price, thus saving Rollup two additional layers of cost.
According to l2 fees, after the Cancun upgrade, Layer2 transaction fees are significantly reduced. Currently, the fee for transferring ETH on Optimism is less than $0.01. While transferring ETH on Ethereum L1 costs about $1.52, before the upgrade in Cancun, transferring ETH on Optimism costs about $0.16. The Cancun upgrade has reduced transaction costs on L2 by tens of times.
This positive change will have a positive impact on Rollup’s TVL, popularity with users, product prosperity and more.
Compete for blob resources
The above-mentioned beneficial effects are theoretical and preliminary. In actuality, Ethereum can only support a certain number of block BLOBs (target value: 3, maximum: 6). Moreover, bloBs have lower gas prices and consumption, and resource competition is inevitable. If many L2 networks vie for the same resources, the cost of the blob will increase initially. Furthermore, it will have an impact on the overall scalability.
Thus, in the long run, it is still necessary to talk about more affordable and scalable alternatives.
There will certainly be increased competition for data as a result of the Cancun upgrade, which could lead some projects to consider alternative DA solutions like Memolabs’ meeda.
Meeda
Meeda is a blockchain data availability (DA) solution introduced by Memolabs to address the data storage and access efficiency issues that exist in current blockchain systems. In a blockchain network, data availability is a key feature that ensures all nodes can access and verify transaction records, and is essential for maintaining the transparency and security of the network.
Meeda’s core strengths are its efficiency and reliability. It significantly reduces storage costs and transaction fees by storing data off-chain while validating data availability on-chain. This approach is particularly well suited to Layer 2 solutions, such as Rollup, which rely on the availability of data on the main chain for security, but at the same time need to process large amounts of transaction data.
How Meeda works involves several key steps. First, the execution layer uploads transaction data to the Meeda network. Next, Meeda generates a Commitment value based on a KZG polynomial commitment, which is used to subsequently verify the availability of the data. The data is then partitioned into multiple slices and stored redundantly via corrective censoring or multiple backup techniques to increase data durability and resistance to attacks.
To ensure the continued availability of data, Meeda employs a multi-round interactive optimistic verification approach. The system periodically generates challenges asking storage nodes to prove that the data they hold is valid. If a node fails to provide a valid proof within a specified time, they are penalised and a data repair mechanism is triggered.
Technical highlights of Meeda include its innovative application of the KZG polynomial commitment, a technique that not only provides an efficient way to verify data integrity, but also reduces the computational cost of the verification process. In addition, Meeda’s Corrective Deletion Code and Multiple Backup mechanisms further improve data availability and security.
With the continuous development of blockchain technology, especially the rapid growth in Web3 and Decentralised Finance (DeFi), there is an increasing demand for efficient and reliable data storage solutions.Meeda provides a cost-effective and high-performance DA solution with a very promising application outlook.
