“Data is king. Or rather, Data Availability (DA) is.” It has the power to make or break a system, and the blockchain is no exception. A blockchain thrives on transparency and trust, but data availability is the backbone that keeps these principles alive. When compromised, it threatens a network’s security.
This article unpacks data availability, why it is essential, and how Ethereum and other specialized blockchains approach it.
What is data availability?
DA refers to the data needed by participants on a blockchain network to verify the correctness of transactions is accessible to them. DA is crucial to nodes’ ability to validate transactions independently, fostering security and decentralization.
Why is data availability important?
Let’s paint a picture of how blockchains operate. Transactions are initially sent to full nodes—servers that keep a complete copy of the blockchain’s data. They are responsible for verifying transactions and blocks to ensure they adhere to the network’s rules.
After receiving and validating these transactions, full nodes package them into blocks and disseminate them across the network. Other nodes then download and re-execute the transactions independently to verify the block’s validity. If validity is confirmed, the nodes add it to their copy, and if not, the block is rejected. This whole process maintains the chain’s integrity and security while remaining decentralized.
Now, imagine if there was no data to work with and no way for nodes to recreate the present state of the blockchain. So many things can and most likely will go wrong, diminishing the strengths of blockchain technology.
How Ethereum rollups handle DA
Ethereum rollups rely on the layer 1 (L1) blockchain to enforce data availability. These scaling solutions send compressed transaction data to the L1. Optimistic rollups send a summary, with the option for fraud proofs to challenge incorrect results. In the case of zk-rollups, cryptographic proof is enough to validate transactions. Still, transaction summaries are necessary to grant more access to the blockchain, including reading and obtaining its contents.
How Non-Ethereum rollups handle data availability
Non-Ethereum rollups use specialized data availability layers. They use blockchains optimized for DA and focus strictly on data storage, as opposed to Ethereum, which combines execution, settlement, and storage.
Ethereum vs. specialized DA layers
Specialized DAs are dedicated to doing one thing, a quality that makes them appear like a great choice. They offer lower costs because they focus on just one role, and they have impressive features like data availability sampling, which allows nodes to check the contents of a block without downloading the entire state—this allows them to increase block sizes cautiously.
However, a network’s (economic) security is crucial for data availability, and Ethereum excels in this aspect compared to specialized DA layers. Its economic security stems from the value of its native token and its proof-of-stake mechanism, which requires an attacker to control a majority of ETH staked, an expensive undertaking.
Rollups that use Ethereum for data availability inherit the network’s security. However, optimized DA blockchains may struggle to match Ethereum’s high-level economic security, especially if their native token lacks significant market value. Weak security could spell doom in several ways—attackers could corrupt or withhold data, affecting the rollup’s ability to operate correctly.
Conclusion
Data availability is the backbone of blockchains, keeping them secure, decentralized, and trustworthy. While specialized DA layers bring scalability and cost efficiency, Ethereum sets itself apart with unmatched economic security. As blockchain technology progresses, finding the sweet spot between security and scalability will determine how data availability evolves and adapts.
For more details about rollups approach to data availability, refer to the original version of this article which was first here.
