golang 100行代码实现区块链原型

有人说今年（2018年）是区块链技术元年，作为一种新兴的技术，它不仅弯道超车盖过了人工智能、大数据的风头，而且发展速度更是一日千里。各大厂商都相继推出区块链服务，你可能觉得难以置信。不管你信不信，当你还在熟睡时，有一群人还在挑灯夜战。

在周未闲来无事，虽然之前网上也有各版本的区块链代码，还是动手用golang写了一下，简单实现了区块链的原型。代码如下：

package main

import (
 "crypto/sha256"
 "encoding/json"
 "fmt"
)

//Block 结构
type Block struct {
 Index        int
 Timestamp    string
 Data         string
 PreviousHash string
 Hash         string
}

//CalculateHash 计算HASH
func (b *Block) CalculateHash() string {
 s := fmt.Sprintf("%d%s%s%s", b.Index, b.PreviousHash, b.Timestamp, b.Data)
 sum := sha256.Sum256([]byte(s))
 return fmt.Sprintf("%x", sum)
}

//BlockChain 结构
type BlockChain struct {
 Chain []*Block
}

//NewBlockChain 创建区块链
func NewBlockChain() *BlockChain {
 bc := &BlockChain{}
 bc.Chain = append(bc.Chain, bc.CreateGenesisBlock())
 return bc
}

//CreateGenesisBlock 创建创世块
func (bc *BlockChain) CreateGenesisBlock() *Block {
 b := &Block{
 Index:        0,
 Timestamp:    "2018-01-01",
 Data:         "Genesis Block",
 PreviousHash: "0",
 }
 b.Hash = b.CalculateHash()
 return b
}

//GetLatestBlock 最新区块
func (bc *BlockChain) GetLatestBlock() *Block {
 return bc.Chain[len(bc.Chain)-1]
}

//AddBlock 增加区块
func (bc *BlockChain) AddBlock(newBlock *Block) {
 newBlock.Index = bc.GetLatestBlock().Index + 1
 newBlock.PreviousHash = bc.GetLatestBlock().Hash
 newBlock.Hash = newBlock.CalculateHash()
 bc.Chain = append(bc.Chain, newBlock)
}

//IsChainValid 区块是否有效
func (bc *BlockChain) IsChainValid() bool {
 for i := 1; i < len(bc.Chain); i++ {
 currentBlock := bc.Chain[i]
 previousBlock := bc.Chain[i-1]

 if currentBlock.Hash != currentBlock.CalculateHash() {
 return false
 }

 if currentBlock.PreviousHash != previousBlock.Hash {
 return false
 }
 }
 return true
}

func main() {
 bc := NewBlockChain()
 bc.AddBlock(&Block{Timestamp: "2018-02-01", Data: `{"amout":10}`})
 bc.AddBlock(&Block{Timestamp: "2018-03-01", Data: `{"amout":20}`})
 bc.AddBlock(&Block{Timestamp: "2018-04-01", Data: `{"amout":30}`})

 blockchain, _ := json.MarshalIndent(bc, "", "\t")
 fmt.Println(string(blockchain))

 fmt.Println("is BlockChain valid ", bc.IsChainValid())
}