Go - 区块链实现

区块链七层架构模型

创建工程文件

mkdir BlockChain && cd BlockChain && go mod init BlockChain
mkdir block blockChain
touch main.go block/block.go blockChain/blockChain.go

数据层

hash

func CalcHash(tobeHash string) string {
    // "crypto/sha256"
    // func Sum256(data []byte) [Size]byte
    // size = 32, 32 byte = 256 bit
    tobeHash_256 := sha256.Sum256([]byte(tobeHash))

    // "encoding/hex"
    // func EncodeToString(src []byte) string
    return hex.EncodeToString(tobeHash_256[:])
}

block

• 类定义

  // block
  type Block struct{
      Index         int64  // 区块编号
      Timestamp     int64  // 区块时间戳
      PrevBlockHash string // 上一个区块的哈希值
      Data          string // 当前区块数据
      Hash          string // 当前区块哈希值
  }

• 方法

  计算当前区块哈希值

  func CalcHash(b *Block) string {
      total_block_data := string(Index) + string(Timestamp) + b.PrevBlockHash + b.Data
      block_data_sha256 := sha256.Sum256([]byte(total_block_data))
      return hex.EncodeToString(block_data_sha256[:])
  }

  生成区块

  func GenerateBlock(prevBlock *Block, data string) *Block{
      new_block := Block{}
      new_block.Index = prevBlock.Index + 1
      new_block.Timestamp = time.Now().Unix()
      new_block.PrevBlockHash = prevBlock.PrevBlockHash
      new_block.Data = data
      new_block.Hash = CalcHash(&new_block)
      
      return &new_block
  }

  创世块(第一个block)

  func GenesisBlock() *Block{
      prevBlock := Block{}
      prevBlock.Index = -1
      prevBlock.PrevBlockHash = ""
      return GenerateBlock(&prevBlock, "Genesis Block")
  }

• 测试

  package main
  
  import(
      "fmt"
  )
  
  func main(){
      a := GenesisBlock()
      b := GenerateBlock(a, "first block")
      fmt.Println(a)
      fmt.Println(b)
  }

  $ go run main.go  
  &{0 1666282848  Genesis Block 90d7d6d9adc8a6dd4eca1e30d8c1a8556a8e3e508da81f30a9e520c2ee7124b0}
  &{1 1666282848 90d7d6d9adc8a6dd4eca1e30d8c1a8556a8e3e508da81f30a9e520c2ee7124b0 first block 16f4d5551953062eca3e7858c28726967d6129f03ac393175efb6044e797589b}

blockchain

• 类定义

  type BlockChain struct{
      Blocks []*block.Block
      Count int64
  }

• 初始化区块链

  func NewBlockChain() *BlockChain{
      bc := BlockChain{}
      bc.Blocks = append(bc.Blocks, block.GenesisBlock())
      bc.Count++
      return &bc
  }

• 区块链直接增加区块

  func (bc *BlockChain) AddBlock(newBlock *block.Block){
      if bc.Count == 0 {
          bc =  NewBlockChain()
      }
      // 判断新增区块是否有效
      if isValid(newBlock, bc){
          bc.Blocks = append(bc.Blocks, newBlock)
          bc.Count++
      }else{
          panic("invalid block")
      }
  }

• 判断新增区块是否有效

  func isValid(newBlock *block.Block, bc *BlockChain) bool {
      oldBlock := bc.Blocks[bc.Count - 1]
      if newBlock.Index - 1 != oldBlock.Index{
          return false
      }
      if newBlock.PrevBlockHash != oldBlock.PrevBlockHash{
          return false
      }
      if block.CalcHash(newBlock) != newBlock.Hash{
          return false
      }
      return true
  }

• 写区块链并增加区块

  func (bc *BlockChain) Write(data string){
      oldBlock := bc.Blocks[bc.Count - 1]
      newBlock := block.GenerateBlock(oldBlock, data)
      bc.AddBlock(newBlock)
  }

• 打印区块链

  func (bc *BlockChain) Print(){
      for _, b := range bc.Blocks{
          fmt.Printf("Index: %d ", b.Index)
          fmt.Printf("Timestamp: %d ", b.Timestamp)
          fmt.Printf("PrevBlockHash: %s ", b.PrevBlockHash)
          fmt.Printf("Data: %s ", b.Data)
          fmt.Printf("Hash: %s\n", b.Hash)
      }
  }

• 测试

  package main
  
  import(
      "BlockChain/blockChain"
  )
  
  func main(){
      bc := blockChain.NewBlockChain()
  
      bc.Write("first block")
      bc.Write("second block")
      bc.Print()
  
  }

  $ go run main.go                                                                            
  Index: 0 Timestamp: 1666286818 PrevBlockHash:  Data: Genesis Block Hash: 90d7d6d9adc8a6dd4eca1e30d8c1a8556a8e3e508da81f30a9e520c2ee7124b0
  Index: 1 Timestamp: 1666286818 PrevBlockHash: 90d7d6d9adc8a6dd4eca1e30d8c1a8556a8e3e508da81f30a9e520c2ee7124b0 Data: first block Hash: 16f4d5551953062eca3e7858c28726967d6129f03ac393175efb6044e797589b
  Index: 2 Timestamp: 1666286818 PrevBlockHash: 16f4d5551953062eca3e7858c28726967d6129f03ac393175efb6044e797589b Data: second block Hash: ad14b2a702a2a1d6765190c84128daca2fa350396b80e95aeb1aaa9e5c77aa11