Alephium

The protocol's innovations extend battle-tested ideas from Bitcoin and Ethereum:

BlockFlow algorithm based on UTXO model enables sharding and scalability for today (code + algorithm paper) The first sharding algorithm that supports single-step cross-shard transactions, offering the same user experience as single chain Simple and elegant PoW based sharding, does not rely on beacon chain Stateful UTXO model combines the advantages of both eUTXO model and account model (see code, wiki to come) Tokens are first-class citizens and UTXO-based, which are owned by users directly instead of contracts Offer the same expressiveness as account model. DApps can be easily built on top of it with better security Support multiple participants in a single smart contract transaction. Multiple calls can be packed into a single transaction too. Novel VM design resolves many critical challenges of dApp platforms (see code, wiki to come) Less IO intensive Flash loan is not available by design Eliminate many attack vectors of EVM, including unlimited authorization, double dip issue, reentrancy attack, etc UTXO style fine-grained execution model reduces risk-free arbitrage Front-running mitigation through random execution of transactions (see code, wiki to come) PoLW algorithm reduces the energy consumption of PoW in the long term (research paper) Adaptive rewards based on hashrate and timestamp are designed and implemented Internal mining cost through burning will be activated when hashrate and energy consumption is significantly high