Qtum at a glance
Simply put, Qtum is an open source Blockchain project put forth by the Singapore-based Qtum Foundation. It’s widely seen as a “hybrid blockchain application platform“. The project’s underlying technology is a fork of bitcoin core, an “Account Abstraction Layer” (AAL) allowing for multiple Virtual Machines including the Ethereum Virtual Machine (EVM) and a Proof-of-Stake consensus. This is designed for a smooth execution of Smart Contracts and Decentralized Applications (DAPPs). The AAL acts here as a bridge between the EVM and the Unspent Transaction Output (UTXO) model of Bitcoin Core.
Without a computer science background, you are probably tearing your hair out by now. So, let’s explain this in English: it’s a project that improves on the Ethereum blockchain, with industry use cases, scalability, and ease-of-implementation in mind.
What are these improvements on the existing Ethereum Blockchain?
First, it doesn’t use proof-of-work for transaction validation, to avoid any jeopardy to the oevrall scalability. It’s precisely the reason why Ethereum is hardly overlapping most industrial applications.
Second, Qtum is well aware of the security flaws that might exist on the ETH blockchain. These flows certainly explain the multiple hard forks yielding several Ethereum versions. In fact, more forks will take place to implement proof-of-stake consensus.
Furthermore, Qtum needs no mining, nor will it require a fork. The project praises itself for being modular, optimized, and designed thoroughly for a readily industry adoption.
How does it work?
Qtum is not simply a Bitcoin and Ethereum fork. It takes an incredible engineering savvy to combine an unspent transaction output (UTXO) blockchain with the EVM (Ethereum Virtual Machine). I know, talk geeky to me. So the Qtum’s solution, or the Account Abstract Layer (AAL), serves as an interface layer between the blockchain and the EVM.
The breakthrough here is to use any smart contracts VM compatible with the AAL as a replacement for EVM. The Quantum team has already announced plans to develop an x86 smart contracts virtual machine for Qtum. Such architecture would make up for the drawbacks found in Solidity (the programing language for implementing smart contracts on the Ethereum Blockchain) and the EVM. For one, it allows developers to program smart contracts in popular programming languages like C, C++, C#, and Java.
Finally, Qtum’s version of Bitcoin Core is known as the Decentralized Governance Protocol (DGP). DGP allows owners to vote on and enables changes to a limited set of blockchain parameters (e.g. block size and block time) without the need of hard forks.
https://en.decentral.news/2017/12/16/qtum-sleeping-giant-china/ 
