KeyChain builds a user-owned, censorship-resistant, and seamless cross-chain Web3 gateway through a hybrid DEX engine (AMM + order book + AI slippage optimization), quantum-safe wallet (MPC + SPHINCS++ hardware SE), and chain-abstract accounts (unified management of 30+ chain assets), with a forward-looking approach to post-quantum security. The KeyChain applications collectively form the "golden triangle" of Web3.0 infrastructure—Trusted Computing Layer (bridging the physical world), Value Exchange Layer (DEX/credit protocols), and Asset Digitalization Layer (RWA/title certificates), with technological breakthroughs in scalability and the collaborative evolution of modular blockchains. KeyChain unlocks the key to 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 blockchain foundation that seamlessly connects the real and digital worlds, becoming the core engine for humanity's transition to a trusted digital society. By combining cutting-edge academic achievements (such as quantum security and federated learning) with extreme engineering design, the KEY chain redefines the boundaries of public chain possibilities. #KEY