建立區塊鏈之v2實現pow（ProofOfWork工作量證明）

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block.go

package mainimport (    "time")//定義塊結構type Block struct{    Version int64    PrevBlockHash []byte    Hash []byte    TimeStamp int64    TargetBits  int64    Nonce int64    MerKelRoot []byte    Data []byte}//設定建立塊的方法func NewBlock(data string, prevBlockHash []byte) *Block{    block := &Block{        Version:1,        PrevBlockHash:prevBlockHash,        //Hash:        TimeStamp:time.Now().Unix(),        TargetBits:10,        Nonce:0,        MerKelRoot:[]byte{},        Data:[]byte(data),    }    //block.SetHash() //設定區塊的雜湊值--->>> v2中來自工作量證明    pow := NewProofOfWork(block)    nonce, hash := pow.Run()    block.Hash = hash    block.Nonce = nonce    return block}// 添加雜湊值---->> v2中來自pow//func (block *Block)SetHash(){//  tmp := [][]byte{//      //實現int類型轉換為byte類型的工具函數//      IntToByte(block.Version),//      block.PrevBlockHash,//      IntToByte(block.TimeStamp),//      block.MerKelRoot,//      IntToByte(block.Nonce),//      block.Data,//  }//  //將區塊的各個欄位連結成一個切片，使用【】byte{}進行連結，目的是避免汙染源區塊的資訊//  data := bytes.Join(tmp,[]byte{})////  //對區塊進行sha256雜湊演算法，傳回值為[32]byte數組，不是切片//  hash := sha256.Sum256(data)//  block.Hash = hash[:]//由數群組轉換為切片//}// 創世塊的建立，它的錢一個去魁岸的雜湊值為空白func NewGenesisBlock() *Block{    return NewBlock("Genesis Block!",[]byte{})}

blockchain.go

package mainimport "os"//定義區塊鏈條type  BlockChain struct{    blocks []*Block}// 建立區塊鏈，並且添加創世塊func NewBlockChain() *BlockChain{    return &BlockChain{[]*Block{        NewGenesisBlock(),    }}}//添加區塊func (bc *BlockChain)AddBlock(data string){    //簡單校正    if len(bc.blocks) <= 0 {        os.Exit(1)    }    //根據上一區塊，建立新的區塊    lastblock := bc.blocks[len(bc.blocks)-1]    prevBlockHash := lastblock.Hash    block := NewBlock(data, prevBlockHash)    //添加到區塊鏈當中    bc.blocks = append(bc.blocks, block)}

utils

package mainimport (    "bytes"    "encoding/binary"    "fmt"    "os")func IntToByte(num int64)[]byte{    var buffer  bytes.Buffer    err := binary.Write(&buffer, binary.BigEndian, num)    //if err != nil{    //  fmt.Println("IntToByte err occur:",err)    //  os.Exit(1)    //}    CheckErr(err)    return buffer.Bytes()}func CheckErr(err error){    if err != nil{        fmt.Println("err occur:",err)        os.Exit(1)    }}

proofOfWork.go

package mainimport (    "math/big"    "bytes"    "math"    "crypto/sha256"    "fmt")const targetBits = 24 //假定難度值type ProofOfWork struct{    block  *Block    targetBit  *big.Int}func NewProofOfWork(block *Block) *ProofOfWork{    var IntTarget = big.NewInt(1)   // 假定值    //000000000000000000000000000000001 初始值    //100000000000000000000000000000000 十進位    //000000000100000000000000000000000 十進位    //000001000000000000000000000000000 十六進位 目標雜湊值    //0000000a0000000000001234560000000 實際值    IntTarget.Lsh(IntTarget, uint(256- targetBits))    return &ProofOfWork{block,IntTarget}}func (pow *ProofOfWork)PrepareRawData(nonce int64) []byte{    block := pow.block //擷取需要處理的區塊    tmp := [][]byte{        //實現int類型轉換為byte類型的工具函數        IntToByte(block.Version),        block.PrevBlockHash,        IntToByte(block.TimeStamp),        block.MerKelRoot,        IntToByte(nonce),        IntToByte(targetBits), //添加難度值        block.Data,    }    //將區塊的各個欄位連結成一個切片，使用【】byte{}進行連結，目的是避免汙染源區塊的資訊    data := bytes.Join(tmp,[]byte{})    return data}func (pow *ProofOfWork)Run()(int64, []byte){    var nonce int64    var hash [32]byte    var HashInt big.Int    fmt.Println("Begin Minng ...")    fmt.Printf("target hash : %x\n", pow.targetBit.Bytes())    for nonce < math.MaxInt64{        data := pow.PrepareRawData(nonce)        hash = sha256.Sum256(data) //取出來後是字串        HashInt.SetBytes(hash[:]) //將byte值轉換為大的數字        // 比較雜湊值        if HashInt.Cmp(pow.targetBit) == -1{            fmt.Printf("Found Hash:%x\n", hash)            break        }else{            nonce ++        }    }    return nonce, hash[:]}//提供外部校正的方法func (pow *ProofOfWork)IsValid()bool{    data :=pow.PrepareRawData(pow.block.Nonce)    hash := sha256.Sum256(data)    var IntHash big.Int    IntHash.SetBytes(hash[:])    return  IntHash.Cmp(pow.targetBit) == -1}

main.go

package mainimport "fmt"func main(){    bc := NewBlockChain()    bc.AddBlock("班長轉給老師一枚比特幣")    bc.AddBlock("班長又轉給老師一枚比特幣")    for i, block := range bc.blocks{        fmt.Println("====block num:", i)        fmt.Printf("Data:%s\n", block.Data)        fmt.Println("Version:",block.Version)        fmt.Printf("PrevHash:%x\n",block.PrevBlockHash)        fmt.Printf("Hash:%x\n",block.TimeStamp)        fmt.Printf("TimeStamp:%d\n",block.TimeStamp)        fmt.Printf("MerKel:%x\n",block.MerKelRoot)        fmt.Printf("Nonce:%d\n",block.Nonce)        //        pow := NewProofOfWork(block)        fmt.Printf("IsvALID:%v\n",pow.IsValid())        }}

最終啟動並執行效果如下所示：

Begin Minng ...target hash : 010000000000000000000000000000000000000000000000000000000000Found Hash:00000014312c76058b55905dbf9915019c484df5f64b9655d01985e050e16eddBegin Minng ...target hash : 010000000000000000000000000000000000000000000000000000000000Found Hash:000000d3c28e9cff07f43949c6c6f23444c1beb7494aebb3be5cf74614e77f04Begin Minng ...target hash : 010000000000000000000000000000000000000000000000000000000000Found Hash:0000004b9205eab846bcf921c952ea2a91e103a4c37170304c4e1bb85d32d73e====block num: 0Data:Genesis Block!Version: 1PrevHash:Hash:5bd09d11TimeStamp:1540398353MerKel:Nonce:26865217IsvALID:true====block num: 1Data:班長轉給老師一枚比特幣Version: 1PrevHash:00000014312c76058b55905dbf9915019c484df5f64b9655d01985e050e16eddHash:5bd09d35TimeStamp:1540398389MerKel:Nonce:6908425IsvALID:true====block num: 2Data:班長又轉給老師一枚比特幣Version: 1PrevHash:000000d3c28e9cff07f43949c6c6f23444c1beb7494aebb3be5cf74614e77f04Hash:5bd09d42TimeStamp:1540398402MerKel:Nonce:70302967IsvALID:true

建立區塊鏈之v2實現pow（ProofOfWork工作量證明）