DepChain: A Dependable Permissioned Blockchain System

Overview

DepChain is a permissioned blockchain system implementing the Byzantine Read/Write Epoch Consensus algorithm, designed to provide high dependability guarantees. The system tolerates up to f Byzantine failures in a 3f+1 node configuration.

Key Features

• Byzantine Fault Tolerant consensus
• Permissioned blockchain with static membership
• Strong cryptographic security with digital signatures
• Smart contract support with ERC-20 token implementation
• Blacklist functionality for regulatory compliance

Prerequisites

• Java JDK 11+
• Maven 3.6+

Quick Start

Building the Project

make build

Key Generation

Generate key pairs for blockchain members:

make keys        # Generates 5 key pairs by default
make keys N=7    # Generate custom number of key pairs

Keys are stored in src/main/java/pt/tecnico/ulisboa/keys/.

Testing Components

make test

This runs tests for authenticated perfect links and solidity contracts, ensuring these two components work correctly independently of the rest of the code. Tests are located in /depchain/src/test/java/pt/tecnico/ulisboa/. Go to the test files to see what exactly is being tested.

Running the System

Launch Blockchain Network

make consensus

This command:

• Starts 4 blockchain servers in the background
• Launches an interactive client (ID: -1)
• This client is the owner of IST tokens with control over the blacklist and the initial supply and can be used to run the commands displayed in the terminal.

Add Additional Client

To test multi-client transactions:

make client

This launches a second client (ID: -2) in a separate terminal that automatically connects to the running network.

Smart Contracts

The system includes two primary smart contracts:

• ISTCoin: An ERC-20 token with custom transfer rules
• Blacklist: Security contract for access control

Aditional Byzantine behaviour tests

Under the /depchain/src/main/java/pt/tecnico/ulisboa/scripts/ directory there are a bunch of scripts we used to test byzantine behaviour.

Note

For detailed implementation information, please refer to the accompanying project report. This README focuses on setup and execution instructions.