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.
EtherZero, abbreviated ETZ, is a hard fork on ethereum providing no-fee, high expansibility, real-time transaction or operation feedback services. Aiming to be a general-purpose smart contract platform, ETZ helps developers set up DAPPs that not limited in finance and business scope, but those more frequently used in daily life, to popularize decentralized services to more people and industries. ETZ eliminates the gas fee system from Ethereum network core and adds a Transaction Restriction Policy Protocol layer that associates the threshold, frequency, depth, etc. of initiating transactions with the account balance to combat DDOS like attacks. In particular, ETZ also draws on DASH's two-tier network architecture built with Masternodes transaction verification network and blockchain ledger layer, and its built-in community autonomous system to provide users with real-time operation feedback and high transaction concurrency, no longer need to wait for a long transaction confirmation time. ETZ picks the proven experience of Ethereum on smart contracts, removes its less scalability gas-based fee system and designs a fully accountable trading limit and security strategy against DDOS Class attacks. The final two-tier network composed of the main node and pow consensus layer laid the foundation to achieve free of charge, high concurrency, real-time transactions, independent evolution and several other features. What does no-fee mean to DApp Dev? Taking a simple Todolist DApp as an example, its decentralized implementation can be applied to the team task decomposition process, which requires all participants in the project to know the tasks of other members. Each task is a team consensus result with demand of traceability. The application involves registration of members, additions, deletions and alterations of tasks. According to Ethereum development requirements, all of these operations require gas consumption, which is clearly unreasonable for the users of the application. While in EtherZero, the transaction initiation frequency and the execution depth of smart contracts will be positively related to the balance possessed by the account. This mechanism is similar to POS, it takes into account the fair use of bandwidth and set a relatively high capital threshold required to launch a DDOS attack by malicious attackers while providing free services. This kind of limited and cost-effective free mechanism will spread the decentralized application into the scene of life.