This wiki contains the documentation of Alephium, a sharded blockchain that makes programmable money scalable and secure.


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 added when hashrate and energy consumption is significantly high