KEY public chain - KeyChain - is the world's first public chain protocol with "full-dimensional intelligence" as its core. It integrates layered heterogeneous architecture, quantum-resistant security technology, zero-delay cross-chain interoperability protocol and environmental adaptive consensus mechanism, aiming to break through the limitations of the "impossible triangle" of traditional blockchains and build a high-performance infrastructure that supports 10,000-level TPS, millisecond-level confirmation and zero-friction cross-ecological collaboration in the Web3.0 era. This solution not only opens the key for individuals to enter the future blockchain world, but also provides institutions and developers with a low-threshold underlying platform that does not require permission and takes into account the principle of decentralization. By continuously optimizing the technical architecture and introducing cutting-edge technologies, the KEY public chain is paving the way for breaking technical barriers and realizing global distributed applications, and also providing strong support for the growing demand for blockchain applications.