• 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, empowering applications like Ordinals, Layer 2s, and price oracles, thus broadening the scope and efficiency of the Bitcoin ecosystem. 

• Bitcoin-Based Security: Nubit inherits Bitcoin's security features, including economic security, tamper resistance, and censorship resistance, by using Bitcoin staking and anchoring methods.
• Scalable Network Architecture: Nubit scales its network through Data Availability Sampling (DAS), which involves Full Storage Nodes and Light Clients.
• Efficient Data Verification: Full Storage Nodes store and send data to Light Clients, which only need block headers and partial data to verify data availability, making them user-friendly for ordinary users.

Three types of nodes participate in DAS:

• Validator: Validators are responsible for running the sampling protocol within the validator set. A validator will sign the block header only if the output of the sampling protocol is successful, thereby ensuring the data’s availability within the validator group.
• Full Storage Node: Once a block is finalized, full storage nodes take on the entire block by employing the decoding protocol with the validator set. These nodes then respond to chunk requests from light clients.
• Light Client: Light clients obtain the block header from a validator and engage in the sampling protocol with a full storage node. If the protocol is successful after sufficient sampling, the block is considered available, and the full storage node’s reputation is enhanced.

• Nubit’s security model is founded on a set of critical assumptions, each playing a vital role in maintaining the network’s integrity and functionality:
• Honest Validators: Network integrity relies on a majority of validators being honest, ensuring reliable bridge operations and block validity.
• Effective Data Availability Sampling (DAS): Light clients and Full Nodes use DAS to maintain data accessibility for validation, even though light clients don't store all data.
• 1-to-N Full Node Security Model: Bitcoin anchoring reduces withdrawal times to less than four hours and adds security checkpoints for enhanced protection.
• Formal Verification: The Nubit team and external auditors will use formal verification to rigorously assess the security of critical infrastructure like the bridge and consensus algorithm.