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 $15.7 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.
Zen is a decentralized financial platform, built from scratch with the goal of providing people with a secure, scalable and useful infrastructure for creating their own financial instruments, and trading them directly without intermediaries.The Zen blockchain is secured by multiple proof-of-work algorithms, with token-holder voting on the balance between them. Multi-hash mining creates robust incentives for miners to deliver efficient, reliable security.Zen smart contracts are written and secured by a subset of the F* functional programming language, allowing users to: A) Prove the amount of resources a contract will consume and provide the necessary fees for running the contract to miners, removing the need for a “gas” based system.B) Prove their contracts meet a given specification, meaning they can prove the contract will definitely do (or not do) something given a specific set of parameters.The Zen platform comes with a built-in solution for oracles, which provide contracts with useful real world data.Finally, Zen is integrated with the Bitcoin blockchain, allowing contracts to observe and respond to native bitcoin transactions