Tiny Blockchain

A blockchain built in Go; merkle trees, transaction validation, and peer-to-peer consensus across multiple nodes.

How it works

Each block contains a set of transactions, a merkle root computed from them, a reference to the previous block's hash, and a nonce. Mining means searching for a nonce that produces a hash starting with enough leading zeros to satisfy the configured difficulty. When a node mines a block, it broadcasts its full chain to its peers, who adopt it if it's longer than their own; a simple longest-chain consensus rule.

Pairs well with raft-consensus; different mechanism, same underlying problem: how do independent nodes agree on a single shared truth.

Project structure

internal/block/
├── block.go
└── merkle.go
internal/chain/
├── chain.go
└── validation.go
internal/wallet/
└── wallet.go
internal/network/
├── server.go
└── client.go
cmd/node/
└── main.go

Running locally

Open three terminals:

go run cmd/node/main.go 7001 localhost:7002,localhost:7003
go run cmd/node/main.go 7002 localhost:7001,localhost:7003
go run cmd/node/main.go 7003 localhost:7001,localhost:7002

Submit a transaction and mine it:

curl -X POST http://localhost:7001/transaction -d '{"from":"alice","to":"bob","amount":50}'
curl -X POST http://localhost:7001/mine

Check that it propagated:

curl http://localhost:7002/chain
curl http://localhost:7003/chain

Tech

• Go
• SHA-256 for hashing and merkle trees
• Plain HTTP for peer-to-peer communication
• No external dependencies