feat: 增加工作量证明#1

.gitignore

@@ -0,0 +1,2 @@
+
+.idea/workspace.xml

src/coin/main.go

@@ -15,6 +15,12 @@ func main() {
 		fmt.Printf("Hash:%x\n", block.Hash)
 		fmt.Printf("Data:%s\n", block.Data)
 		fmt.Printf("PrevHash:%x\n", block.PrevBlockHash)
+
+		// 验证
+		pow := core.NewProofOfWork(block)
+		fmt.Println("POW:", pow.Validate())
+
+		fmt.Printf("\n\n")
 	}
 
 }

src/core/block.go

@@ -12,12 +12,16 @@ type Block struct {
 	Hash          []byte // Hash值
 	PrevBlockHash []byte // 上一个区块的Hash值
 	Timestamp     int64  // 时间戳
+	Nonce         int    // 工作量证明
 }
 
 // 生成一个新的区块
 func NewBlock(data string, prevBlockHash []byte) *Block {
-	block := &Block{[]byte(data), []byte{}, prevBlockHash, time.Now().Unix()}
-	block.SetHash()
+	block := &Block{[]byte(data), []byte{}, prevBlockHash, time.Now().Unix(),0}
+	pow := NewProofOfWork(block)
+	nonce, hash := pow.Run()
+	block.Hash = hash[:]
+	block.Nonce = nonce
 	return block
 }
 

src/core/proofofwork.go

@@ -0,0 +1,67 @@
+package core
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"math"
+	"math/big"
+	"fmt"
+)
+
+var (
+	maxNonce = math.MaxInt64
+)
+// 困难度，数越大越困难
+const targetBits = 8
+
+type ProofOfWork struct {
+	block  *Block
+	target *big.Int
+}
+// 创建一个新的工作量证明
+func NewProofOfWork(block *Block) *ProofOfWork {
+	target := big.NewInt(1)
+	// 左移
+	target.Lsh(target, uint(256-targetBits))
+	pow := &ProofOfWork{block, target}
+	return pow
+}
+// 准备数据
+func (pow *ProofOfWork) prepareData(nonce int) []byte {
+	data := bytes.Join([][]byte{
+		pow.block.PrevBlockHash,
+		pow.block.Data,
+		IntToHex(pow.block.Timestamp),
+		IntToHex(targetBits),
+		IntToHex(int64(nonce)),
+	}, []byte{})
+	return data
+}
+// 挖矿
+func (pow *ProofOfWork) Run() (int, []byte) {
+	var hashInt big.Int
+	var hash [32]byte
+	nonce := 0
+	for nonce < maxNonce {
+		data := pow.prepareData(nonce)
+		hash = sha256.Sum256(data)
+		fmt.Printf("\r%x",hash)
+		hashInt.SetBytes(hash[:])
+		if hashInt.Cmp(pow.target) == -1 {
+			break
+		}else {
+			nonce++
+		}
+	}
+	return nonce,hash[:]
+}
+
+// 验证
+func (pow *ProofOfWork)Validate() bool {
+	var hashInt big.Int
+	data := pow.prepareData(pow.block.Nonce)
+	hash := sha256.Sum256(data)
+	hashInt.SetBytes(hash[:])
+	isValidate := hashInt.Cmp(pow.target) == -1
+	return isValidate
+}

src/core/utils.go

@@ -0,0 +1,16 @@
+package core
+
+import (
+	"bytes"
+	"encoding/binary"
+	"log"
+	)
+
+func IntToHex(num int64) []byte  {
+	buff := new(bytes.Buffer)
+	err := binary.Write(buff, binary.BigEndian, num)
+	if err!=nil {
+		log.Panic("failed Int to hex:",err)
+	}
+	return buff.Bytes()
+}