In its whitepaper, Qtum is the original UTXO-based smart contract system with a proof-of-sale (PoS) accord model. This suggests that it puts in unspent coins from many transactions into the user's wallet and chooses the next producer node-based on the quantity of coins carried by each node. This helps to achieve two purposes. The first is safety.
As some examples have shown over the years, Ethereum's blockchain is vulnerable to hacks. Bitcoin, on the other hand, has been demonstrated to be relatively secure. The second motive is to make it simple to mine new coins. Bitcoin's proof of work algorithm is resource-intensive. A proof-of-stake algorithm facilitates the procedure to produce a new block and eats much less power as correlated to Bitcoin. Qtum utilizes UTXO laws, which is run on a machine operating on Ethereum's virtual machine, which uses an account-based model.