Why We Need Nubit: A Comparative Analysis of Bitcoin-Native Data Availability Layer
The recent surge in demand for Bitcoin inscriptions has led to over 14GB of data being stored on the Bitcoin blockchain, incurring significantly high costs. This development underscores a critical need within the Bitcoin ecosystem — an efficient and cost-effective data availability layer. Addressing this need, Riema Labs has taken the lead by launching Nubit, the first Bitcoin-native data availability layer, guided by the principle of trust minimization.
Nubit is a scalable, cost-efficient, data availability layer secured by Bitcoin for the Bitcoin community. Nubit enables the scaling of Bitcoin’s data capacities without compromises, empowering applications like Ordinals, Layer 2s, and price oracles, thus broadening the scope and efficiency of the Bitcoin ecosystem.
The figure below explores the benefits of Nubit, including security inheritance from Bitcoin, trust minimization, and native alignment with Bitcoin. It presents Nubit’s core elements: consensus mechanism, data availability, and trustless bridge, each empowered by Bitcoin.
The subsequent discussion will offer in-depth insights into these three elements and their comparison with other solutions to highlight Nubit’s distinctive role in the Bitcoin ecosystem.
Consensus Mechanism
Before discussing consensus mechanisms, it’s crucial to define network assumptions. Current non-asynchronous BFT consensus algorithms are based on semi-synchronous network assumptions. In such a setting, networks are expected to deliver within a certain timeframe, and BFT can only operate effectively in relatively ‘private’ networks with stable node connections. The famous FLP impossibility theorem states that achieving deterministic consensus in asynchronous consensus algorithms is impossible if even one node may crash. Given the operational realities of blockchains today, no project can guarantee the infallibility of a single node.
In light of this, Nubit’s consensus mechanism still adheres to the semi-synchronous network assumption. We introduce NuBFT, a consensus algorithm deeply optimized for Data Availability (DA). In particular, NuBFT is a variation of the BFT consensus algorithm and incorporates the data partition process based on Reed-Solomon Coding (RS-coding) and the generation of KZG commitments. The use of RS-coding allows for restoring original data even if some data nodes are compromised, as the intact data can be reconstructed from the remaining normal nodes. Additionally, KZG commitments submitted to Bitcoin ensure the validity of the original data. By integrating the block partition of RS-coding and the generation of KZG commitments into the consensus algorithm, the integrity, availability, and scalability of the stored data are directly tied to the consensus process, significantly enhancing the robustness of the entire DA system.
Furthermore, Nubit uses Bitcoin as its primary token for consensus protocols, inheriting Bitcoin’s economic security through Bitcoin-native staking mechanisms like Babylon. In contrast, generic DA layers like Celestia use their network tokens, introducing additional trust assumptions outside of Bitcoin.
With a complete redesign of the consensus layer, Nubit aims to reduce data storage costs by 10–30 times, while ensuring complete data availability. This approach significantly lowers the participation threshold for Nubit network nodes, making the shared security with Bitcoin practically feasible.
Data Availability
To address potential network disruptions caused by incorrect data encoding by nodes, Nubit adopts a hybrid approach, integrating full nodes and light nodes to ensure data integrity.
Firstly, Nubit employs KZG commitments as validity proof to ensure DA, reducing memory, bandwidth, and storage requirements while maintaining succinctness.
Even in the event of a complete Nubit network collapse, nodes can still perform data restoration using full nodes and KZG commitments submitted on Bitcoin. This robustness significantly guarantees network integrity and achieves a 1-of-N trust assumption. In contrast, generic DA layers like Celestia do not use or inherit trust from Bitcoin.
To further enhance network scalability, Nubit incorporates light nodes equipped with Data Availability Sampling (DAS). This addition enables the scaling of block sizes to meet the ever-increasing demands for data availability. As a result, the growing block space will not impact applications built on this platform, since light clients are capable of performing DAS without the need to download entire blocks. This data verification method, distinct from the validity proofs, adds another layer of efficiency and scalability to the Nubit network.
Lastly, it’s noteworthy that unlike Bitcoin Layer 2 solutions, which require handling complex state transitions in smart contract executions, Nubit does not possess a smart contract execution layer. This design choice effectively eliminates the additional execution overhead typically associated with smart contracts.
Trustless Bridge
Bridges are essential in blockchain for connecting networks or layers, enabling asset and data transfers. Celestia and Ethereum Layer 2s use advanced methods like the Cosmos IBC protocol and smart contracts for decentralized bridging. However, these approaches don’t suit Bitcoin’s unique design, lacking smart contract capabilities and off-chain state syncing. Consequently, Bitcoin Layer 2s often rely on centralized bridges, creating potential security vulnerabilities due to Bitcoin’s specific architectural constraints.
To navigate these challenges, Nubit adopts a novel approach by utilizing the Lightning Network, a payment channel solution native to Bitcoin. This method enables Nubit to establish a secure, trustless bridge within the Bitcoin ecosystem. Nubit’s use of Bitcoin payment channels for network fee settlements is a key differentiator from other bridge solutions within the Bitcoin ecosystem. Nubit users are not burdened with the requirement of making pre-deposits. Instead, they handle transaction fees directly within the state channels for each transaction, ensuring that the security of users’ funds is directly tied to the security of Bitcoin itself.
Moreover, Nubit’s design allows for emergency withdrawals. Even if Nubit ceases operations, users can recover their funds by closing their payment channels on Bitcoin. This feature enhances user trust and security, as it eliminates reliance on any third-party entities and adheres strictly to the principles of trust minimization.
Summary
Nubit stands out in the blockchain landscape as a Bitcoin-native solution, distinctly different from Celestia and traditional Bitcoin Layer 2 technologies. Its core strength lies in its consensus mechanism, validity proof, and trustless bridge, which collectively ensure a secure and seamless integration within the Bitcoin ecosystem. This integration allows Nubit to leverage the inherent security and trust of Bitcoin, offering a trust-minimized and efficient approach to data availability.
