Chain Fusion allows the Internet Computer Protocol (ICP) to interconnect with multiple blockchains in a decentralized manner, eliminating the need for a single trusted intermediary such as a bridge. The ability of ICP smart contracts to utilise threshold signature schemes to sign and submit transactions directly to other chains enables Chain-key tokens. Each Chain-key token on ICP is backed 1:1 by the native asset and is redeemable at any time. The native wallets are managed by a smart contracts on ICP, there are no intermediaries or centralized bridges. Chain-key tokens begin with ck (e.g. ckBTC, ckETH, etc.). They transact quickly (1 second finality) and transaction fees are negligible.