Qtum is an open source Blockchain project that is developed by the Singapore-based Qtum Foundation. Qtum is a hybrid blockchain application platform. Qtum’s core technology combines a fork of bitcoin core, an Account Abstraction Layer allowing for multiple Virtual Machines including the Ethereum Virtual Machine (EVM) and Proof-of-Stake consensus aimed at tackling industry use cases. We believe this will allow Smart Contracts and Decentralized Applications to run on a familiar foundation, while offering a robust environment for developers. The underlying technology uses an “Account Abstract Layer”, which acts as a bridge between the EVM and the Unspent Transaction Output model of Bitcoin Core. There will be Oracles and Datafeed functionality, allowing developers to create Smart Contracts built around trusted sources of information.
Blockchain-enabled smart contracts that employ proof-ofstake validation for transactions, promise significant performance advantages compared to proof-of-work solutions. For broad industry adoption, other important requirements must be met in addition. For example, stable backwards-compatible smart-contract systems must automate cross-organizational information-logistics orchestration with lite mobile wallets that support simple payment verification (SPV) techniques. The currently leading smart-contract solution Ethereum, uses computationally expensive proof-of-work validation, is expected to hard-fork multiple times in the future and requires downloading the entire blockchain. Consequently, Ethereum smart contracts have limited utility and lack formal semantics, which is a security issue. This whitepaper fills the gap in the state of the art by presenting the Qtum smart-contract framework that aims for sociotechnical application suitability, the adoption of formalsemantics language expressiveness, and the provision of smart-contract template libraries for rapid best-practice industry deployment. We discuss the Qtum utility advantages compared to the Ethereum alternative and present Qtum smart-contract future development plans for industrycases applications.