Qtum is a decentralized and open-source smart contracts platform and value transfer protocol. Qtum uses proof-of-stake consensus, meaning node operators are rewarded for validating transactions. It is a DGP governed blockchain where community participants can vote to change certain network parameters. Qtum is built on a bitcoin core fork, but the foundation has created its own hybrid blockchain with the help of several key tools. The coin uses bitcoin’s chain because of its simple and stable nature, allowing the foundation to build upon it more easily. As the QTUM project is a hybrid of Bitcoin and Ethereum, its team comprises of members from both Bitcoin and Ethereum community. They also have team members who formerly worked with Tencent, Alibaba, Nasdaq etc. Apart from that, they are backed by some notable VCs and prominent people from the Blockchain community such as Patrick Dai (Project Co-Founder), Neil Mahi (Chief Blockchain Architect/Co-Founder) and Jordan Earls (Lead Developer/Co-Founder). Qtum provides a Turing-complete blockchain stack and is able to execute smart contracts and decentralised applications like the Ethereum blockchain. Qtum builds on Bitcoin's UTXO transaction model and uses the Proof-of-Stake algorithm. It is backed by some highly prominent members of the blockchain community such as Anthony Di Iorio, Xu Star, Bo Shen, David Lee, Jehan Chu and Roger Ver. Qtum sold over 10 million dollars’ worth of its tokens after only 90 minutes, eventually raising a total value of .7 million before stopping the campaign early after only 5 days. They raised a total amount of 11,156.766 bitcoins (BTC) and 77,081.031 ether (ETH) in exchange for the 51 million Qtum tokens being distributed to the public. In Qtum’s whitepaper, 51% of the coins were distributed to the public via the crowdfunding campaign. Of the remaining 49%, 29% of the coins would be allocated as community incentives, and the remaining 20% would be distributed to the early backers and development team.

Qtum Blockchain（简称“量子链”或“Qtum”）致力于开发比特币和以太坊之外的第三种区块链生态系统，通过价值传输协议（“Value Transfer Protocol”）来实现点对点的价值转移，并根据此协议，构建一个支持多个行业（包括金融、物联网、供应链、社交、游戏等）的去中心化的应用开发平台（“DApp Platform”）。通过合并改进版本的比特币核心基础架构和可以相互兼容的以太坊虚拟机版本，量子链既拥有比特币坚不可摧的区块链网络又能发挥智能合约的无限可能。QTUM币用于访问Dapp、代币投票、社区自治、应用功能消耗/支付。

一、AAL 账户抽象层

账户抽象层（Account Abstraction Layer, AAL）是 Qtum 连接 UTXO 流通层和智能合约平台层的关键，也是量子链实现的一大创新。通过 AAL 可以将 UTXO 模型转换成可供不同虚拟机执行的账户模型，比如以太坊 EVM，或是 x86 虚拟机，并且可以把虚拟机的帐户余额通过 AAL 转换为 UTXO。
这实现了余额和智能合约平台的分层设计，流动性采用比特币的 UTXO，并且原生支持多重签名算法，作为余额的记账、转账更具有安全性；而由于智能合约平台是图灵完备的，很难避免编程出现 bug，把流通层和和智能合约平台分离比以太坊更具优势。为了使区块链的智能合约平台能力得到进一步的扩展，Qtum 计划实现的 x86 高性能虚拟机可以直接通过 C、C++、rust、go 等语言进行智能合约的编程，也可以支持其他可以在 x86 架构上运行的编程语言。x86 架构虚拟机可以解决以太坊EVM中一些问题，比如不支持标准库、生成的字节码过大、不支持浮点、难以调试等。

二、DGP 治理

DGP 的全称是分布式自治协议（Decentralized Governance Protocol）。其关键是利用智能合约的结果确定性、规则公开性等特点，把治理框架和规则固化到合约中，以便在需要的时候通过民主的方式进行决策，自动化地完成区块链状态管理。

三、Qtum x86 虚拟机

Intel 的 x86 CPU 架构是服务器和桌面计算机的主要 CPU 平台。Qtum 团队正在使用 x86 机器语言开发虚拟机。“虚拟机”是一个独立的软件执行环境，可以在许多不同的硬件平台（Mac、PC、服务器、云端的虚拟私有服务器等）上运行。目前 Qtum 上使用的是 EVM 虚拟机和 solidity。
以太坊的 Solidity 语言是第一个智能合约开发语言。作为一个新的语言，Solidity 存在着一些问题，通过 x86 虚拟机平台开发者可以使用自己熟悉和主流的语言（例如 C 语言、C++ 语言、Rust 和 Python）和工具进行智能合约的开发。

四、项目特点

量子链的主要特点如下：
1.从技术角度分析，Qtum致力于实现首个兼容BIP（基于UTXO模型 ）的POS智能合约平台，兼容比特币交易模式以及以太坊虚拟机优势；
2.量子链通过“去中心应用”和“主控合约”将链下因素引入，形成符合现实世界商业逻辑的区块链主控合约，支持多个行业、多种渠道，最终实现走向移动端策略；
3.加强公有链中和联盟链中共识机制的灵活性，同时考虑行业合规性。

相关链接：

https://qtum.org/zh/about/faq

https://baike.baidu.com/item/%E9%87%8F%E5%AD%90%E9%93%BE/22415320?fr=aladdin