Alephium

This repository contains the reference implementation of Alephium, a sharded blockchain that makes programmable money scalable and secure. For more information, please visit the wiki.

Overview

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
• 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

Installation

Prerequisites

The following dependencies must be installed in order to run the JAR deliverable:

• java (11+)

Running

You can obtain our latest single JAR distribution from the GitHub releases and start the application using the following command:

java -jar alephium-<VERSION>.jar

Build From Source

Requirements

In order to build the project from source the following dependencies must be installed on your system:

• java (11+)
• SBT

Single JAR

Use the following command to build a single runnable JAR :

make assembly

The resulting assembly file will appear in /app/target/scala-2.13/ directory.

Universal Zip distribution

Use the following command to build a zip distribution including launch scripts:

make package

The resulting package file will appear in the app/target/scala-2.13/universal directory.

Docker Image

Use the following command to build a docker image:

make docker

Configuration

You can define user specific settings in the file $ALEPHIUM_HOME/user.conf, where by default $ALEPHIUM_HOME points to ~/.alephium.

Testing

There are two kinds of tests:

1. Unit tests and property based tests, which can be run with the make test command.
2. Integration tests, which can be run with the make itest command.

Contribution

Have a look at our contribution guide described in CONTRIBUTING.md

Acknowledgements

YourKit supports open source projects with innovative and intelligent tools for monitoring and profiling Java and .NET applications. YourKit is the creator of YourKit Java Profiler, YourKit .NET Profiler, and YourKit YouMonitor.