WHAT IS DATA AVAILABILITY?

Blockchain is often lauded for its ability to securely and transparently record data. Transactions are recorded, held in data blocks, and added to the blockchain, which are then locally stored by each node in the network. Ensuring that every transaction data is fully stored in each proposed block is extremely necessary. This is a crucial aspect in maintaining the integrity and reliability of the blockchain network. However, simply trusting the nodes in the network to act honestly is not enough. Their actions must be independently verified, hence the saying "don't trust, verify." The challenge of verifying the Data Availability in each newly proposed block is known as the Data Availability issue. This article will explore the importance of Data Availability for the operation of blockchain networks and the ongoing developments in this field.

What is Data Availability (DA)?

Data Availability (DA) is the assurance of the presence and accessibility of data in a database. In the context of blockchain, DA is the assurance that the proposed block contains data of all transactions that have taken place on the blockchain, and this data is accessible to all members of the network. Without this data, members of the network cannot confirm that a specific event has occurred, which from the perspective of blockchain means the event did not occur. This highlights the importance of DA in maintaining the integrity and reliability of the blockchain network. When building and proposing a new block, the block producer must make all data contained in the block, including transaction data in the body of the block, available for others to view. The storage capacity of the blockchain for new blocks is referred to as block space, a necessary factor for the accessibility of stored data. Therefore, when the block space is filled up, Data Availability might decrease. During the resolution and consensus process, full nodes can download the proposed blocks and re-execute the transactions. Through this process, the validity of each transaction can be confirmed, and the safety of the network can be ensured. Additionally, this also allows for the detection of any malicious transactions that might have been included in the block by the block proposer.

Ensuring Data Availability (DA)

Ensuring Data Availability means guaranteeing that all necessary data for a transaction is available on the blockchain network. It ensures that data stored on the blockchain is available to all nodes and can be accessed at any time. Typically, this is guaranteed through decentralization, requiring each full node in the network to download each proposed block and verify the presence of transaction data before the block is finalized. Each blockchain ensures a certain level of DA depending on its methodology. Some blockchains are specifically designed to provide a high level of assurance.

Ensuring Data Availability plays a critical role in maintaining the safety and trustless nature of blockchains, even when nodes encounter problems or go offline. These guarantees ensure that all nodes have consistent access to the same data and that this data is accurate and valid. This helps prevent malicious data or attempts to tamper with data. Furthermore, ensuring DA allows nodes to independently verify transactions and compute the state of the blockchain without needing to trust each other, ensuring that the blockchain maintains its decentralized nature and has no single point of failure (SPoF).

Innovations to Improve DA

Innovations in blockchain technology are providing new methods to address cost and storage issues related to ensuring DA. Transaction costs have risen on some major blockchains due to the enormous amount of calldata produced by DeFi applications and rollups. Moreover, as these networks become overwhelmed with data, storage issues also increase, as most of them require maintaining a complete network history. However, recent innovations such as data sharding, data accessibility sampling have brought more efficient methods of ensuring DA and providing data storage space. Some notable technological solutions currently aimed at improving Data Availability include Data Availability Sampling, Data Availability Layer, Danksharding, and Proto-Danksharding.

Data Availability is the backbone of any blockchain network. Without it, the network would not function and be unusable. It ensures that all network members have access to data stored on the blockchain, allowing transactions to be effectively, securely, and accurately verified by anyone. Recent advancements, such as specialized DA layers, new transaction formats for BLOBs, and danksharding, are helping to reduce the costs associated with this assurance. Moreover, with the public's shifting perception from single-blockchain to modular blockchain systems, the importance of properly managing the DA layer is increasingly crucial. However, DA remains a fertile area for innovation and future research as new solutions continue to be developed and refined to address issues related to storage and cost.