Qtum is an open sourced public blockchain platform, leveraging the security of UTXO while enabling multiple virtual machines including EVM and the revolutionary x86 VM. Qtum is PoS based and boasts a Decentralized Governance Protocol (DGP) allowing specific blockchain settings to be modified by making use of smart contracts. For instance, the block size of Qtum can be increased without the need of a hard fork.
The adoption of proof-of-stake into Qtum constitutes a considerable saving of computational effort over the not scaling Ethereum alternative that still uses proof-of-work. While Ethereum plans to also adopt proof-of-stake, it is unclear when such a new version will be released. Also the use of unspent transaction outputs is more scalable in comparison to the account management of Ethereum. In combination with simple payment verification, Qtum already develops a smartcontract mobile-device solution. While the not scaling Ethereum solution does not allow for mobile solutions, Qtum aims to achieve a democratized and highly distributed proof-of-stake transaction validation with its mobile strategy. The Qtum-framework has a clear understanding of quality criteria that future developments must satisfy. With respect to functional requirements, Qtum plans to develop an application layer for smart-contract lifecycle management. Most importantly, such lifecycle management is important for vetting collaborating parties to reduce security breaches such as those Ethereum recently experienced, resulting in multiple hardforks of the latter.