Simple Blockchain implementation in Rust

A lightweight, educational blockchain node written in Rust. It demonstrates core distributed ledger concepts including Proof of Work, P2P synchronization, and cryptographic transaction signing.

Features

• SHA-256 Hashing: Secure block and transaction hashing.
• Proof of Work (PoW): Mining mechanism with configurable difficulty.
• P2P Network Sync: TCP-based peer-to-peer chain synchronization.
• ECDSA Signatures: Transaction signing and verification using secp256k1.
• JSON Serialization: State serialization for peer data transfer.
• Unit Tests: Comprehensive test coverage for mining, keys, and transactions.

How to Run

Ensure you have Rust installed. Clone the repository and use the following commands:

# Run the first node on port 8080
cargo run -- 8080

# In a new terminal, run the second node on port 8081, syncing with the first node
cargo run -- 8081 8080

# Run unit tests
cargo test

Example Output

Node 1 (cargo run -- 8080):

valid = true
after tamper = false
Starting node on port 8080...
Listening on 127.0.0.1:8080

Node 2 (cargo run -- 8081 8080):

valid = true
after tamper = false
Starting node on port 8081...
Listening on 127.0.0.1:8081
Received chain from peer. Length: 4
Peer chain is longer! Replacing ours.

Technologies & Crates

• secp256k1: For generating keypairs, signing, and verifying ECDSA transactions.
• tokio: Asynchronous runtime for handling the TCP server and P2P networking.
• serde & serde_json: For serializing and deserializing blocks and the blockchain state.
• hex: For encoding SHA-256 hash byte arrays into readable hex strings.
• rand: For secure random number generation during keypair creation.