Bsquared (B²) Network is an EVM-compatible Rollup built on zero-knowledge proof verification commitment on the Bitcoin blockchain. Rollup data and zk proof verification commitments are recorded on the Bitcoin Network and confirmed through a challenge-response mechanism.B² Network is a Layer-2 solution that bolsters transaction speed and broadens application diversity without sacrificing security. B² Network is the first zero-knowledge proof verification commitment rollup on Bitcoin. Leveraging rollup technology, B² Network provides a platform capable of running Turing-complete smart contracts for off-chain transactions, which enhances transaction efficiency and minimizes costs. Additionally, zero-knowledge proof technology is employed in tandem with gate commitment and challenge-response of Taproot to guarantee transactional privacy and security during confirmation on Bitcoin. The network's objective is to metamorphose Bitcoin into a versatile platform, paving the way for groundbreaking applications such as DeFi, NFTs, and other decentralized systems.