QTUM History
Qtum is a Chinese project which launched in March 2017 when developers conducted an ICO. More than 5000 BTC was raised in the first 10 minutes of the public crowdsale, with the project managing to raise 11156.766 BTC and 77081.031 ETH (about $15.7 million). All tokens were sold during the first 5 days and a total of 100 million QTUMs were issued.
How does QTUM work?
QTUM Blockchain
The Qtum cryptocurrency uses a hybrid blockchain built on a combination of elements from both Bitcoin and Ethereum. The UTXO method (unspent outputs) used for transaction verification was borrowed from BTC and is the most reliable of all existing technologies to avoid double-spending. The operation scheme is very simple: for example, a user wants to send 1 BTC, from his wallet with 5 BTC. Thanks to UTXO, 1 BTC can be transferred to the recipient’s wallet with 4 BTC transferred back to the user's wallet. There are always two inputs when sending coins to a wallet on the network. The UTXO model is not only safe but also more scalable, allowing multiple transactions to be checked simultaneously, regardless of their sequence.
Qtum Account Abstraction Level
The choice of UTXO required the developers to solve a very difficult task: integration with the Ethereum Virtual Machine (EVM). The team used a special technology called "Account Abstraction Layer" - an innovation created specifically for Qtum. Despite the difficult technical implementation, the principle of its operation is very simple: a special algorithm converts UTXO into account balances, making them compatible with Ethereum. Qtum's "Account Abstraction Layer" decouples applications from the underlying protocol, retaining blockchain performance and lending the potential to add more smart contract functionality in the future.
QTUM Master contacts
Independent developers can run Master contracts on the Qtum blockchain, offering more advanced features than ordinary Ethereum smart contracts. Python, Rust, Go, C++ and Lua programming languages can be used to write them and they can react instantly to external circumstances in the network. This is the key difference from Ethereum smart contracts. The work principles of master contracts are explained in the project White Paper as follows: Imagine a situation where a cargo needs to be sent from point A to point B. Only two states: “complete” and “fail” can be recorded in an ordinary smart contract. The Master contract allows connecting another user registered on the Qtum network with, for example, a freight company. The system will track all cargo movements, as well as all intermediate actions of the cargo company. The data is recorded in the blockchain, and the user can track all actions online.
Qtum also uses the DGP (Delegated Governance Protocol): Network participants can vote for changes to the platform and propose their own projects. The consent of the majority is required to implement updates, providing a high level of decentralization.
QTUM PoS ver.3.0
Another feature of master contracts is that they are compatible with the Internet of Things (IoT) and mobile devices. Smart contracts are not suitable, because they use the PoW consensus algorithm, which requires a lot of computing power from the devices. Master contracts are implemented on a special subset of the PoS algorithm, called Proof-of-Stake version 3.0.