KeyChain builds a user-controlled, censorship-resistant, cross-chain seamless Web3 entry point with quantum-safe Wallet (MPC+SPHINCS++ hardware SE), a hybrid DEX engine (AMM + order book + AI slippage optimization), and chain abstract accounts (unified management of 30+ chain assets), while possessing forward-looking post-quantum security. The KeyChain applications together form the "golden triangle" of Web3.0 infrastructure — the trusted computing layer (physical world bridging), the value exchange layer (DEX/credit protocol), and the asset digitization layer (RWA/title certificates), with the technological breakthroughs lying in the synergy evolution of scalability and modular blockchain. KeyChain unlocks the key to the blockchain and the future world for everyone, while the KEY public chain creates a permissionless blockchain suitable for applications for institutions and developers, making Wallets and financial tools more accessible without compromising the core principle of Decentralization. The KEY chain will build a self-evolving, infinitely scalable, seamlessly connecting the real and digital worlds blockchain infrastructure layer, becoming the core engine for humanity's move towards a trusted digital society. By combining cutting-edge academic achievements (such as quantum safety, federated learning) with extreme design in engineering, the KEY chain redefines the boundaries of possibilities for public chains. #key