比特币生成默克尔根算法golang实现

实现代码：

import (
	"encoding/hex"
	"errors"
	"generateAddress/utils"
	"paper/common"
)

type MerkleNode struct {
	Value string
	Left *MerkleNode
	Right *MerkleNode
}

//构建merkle root hash
func ConstructMerkleRoot(txids []string) (*MerkleNode, error) {
	//参数校验
	if len(txids) == 0 {
		return nil,errors.New("txids is empth")
	}

	//开始构建
	var leafNodes []MerkleNode
	for _, txid := range txids {
		var oneLeaf = MerkleNode{Value:txid, Left:nil, Right:nil}
		leafNodes = append(leafNodes, oneLeaf)
	}
	return ConstructMerkleTreeNodes(leafNodes)
}

func ConstructMerkleTreeNodes(nodes []MerkleNode) (*MerkleNode, error) {
	//参数校验
	if len(nodes) == 0 {
		return nil,errors.New("number of nodes is 0")
	}
	if len(nodes) == 1 {
		return &nodes[0],nil
	}
	if len(nodes) == 2 {
		var root = MerkleNode{}
		var err error
		if root,err = Merge(&nodes[0], &nodes[1]); err != nil {
			return nil, err
		}
		return &root,nil
	}

	var (
		err error
		nodeAmount = len(nodes)
		parentNodes []MerkleNode
		left *MerkleNode
		right *MerkleNode
	)

	//处理三个及三个以上的节点
	for i:=0; i< nodeAmount; i += 2 {
		var parentNode = MerkleNode{}
		left = &nodes[i]
		if i == nodeAmount-1 {//最后一个单独的节点
			right = &nodes[i]
		} else {
			right = &nodes[i+1]
		}
		if parentNode,err = Merge(left, right); err != nil {
			return nil, err
		}
		parentNodes = append(parentNodes,parentNode)
	}
	return ConstructMerkleTreeNodes(parentNodes)
}

func Merge(left *MerkleNode, right *MerkleNode) (MerkleNode, error) {
	var (
		parentNode = MerkleNode{Value:"", Left:left, Right:right}
		data []byte
		err error
		leftBytes []byte
		rightBytes []byte
	)
	//计算的时候txid从BigEdian转变成LittleEdian
	if leftBytes,err = utils.ReverseBigEdianString(left.Value); err != nil {
		return MerkleNode{},err
	}
	if rightBytes,err = utils.ReverseBigEdianString(right.Value); err != nil {
		return MerkleNode{},err
	}
	data = append(leftBytes, rightBytes...)
	var parentHash = common.Sha256AfterSha256(data)

	//用字符串显示时保存为小端
	data = utils.ReverseBytes(parentHash[:])
	parentNode.Value = hex.EncodeToString(data)
	return parentNode,nil
}

 

测试代码：

func TestConstructMerkleRoot(t *testing.T) {
	var testcases = []struct {
		txids []string
		merkleRoot string
	} {
		{
			[]string {
				"b1fea52486ce0c62bb442b530a3f0132b826c74e473d1f2c220bfa78111c5082",
				"f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16",
			},
			"7dac2c5666815c17a3b36427de37bb9d2e2c5ccec3f8633eb91a4205cb4c10ff",
		},
		{
			[]string {
				"8347cee4a1cb5ad1bb0d92e86e6612dbf6cfc7649c9964f210d4069b426e720a",
				"a16f3ce4dd5deb92d98ef5cf8afeaf0775ebca408f708b2146c4fb42b41e14be",
			},
			"ed92b1db0b3e998c0a4351ee3f825fd5ac6571ce50c050b4b45df015092a6c36",
		},
		{
			[]string {
				"09e5c4a5a089928bbe368cd0f2b09abafb3ebf328cd0d262d06ec35bdda1077f",
				"591e91f809d716912ca1d4a9295e70c3e78bab077683f79350f101da64588073",
			},
			"2f0f017f1991a1393798ff851bfc02ce7ba3f5e066815ed3104afb4bd3a0c230",
		},
		{
			[]string{
				"8c14f0db3df150123e6f3dbbf30f8b955a8249b62ac1d1ff16284aefa3d06d87",
				"fff2525b8931402dd09222c50775608f75787bd2b87e56995a7bdd30f79702c4",
				"6359f0868171b1d194cbee1af2f16ea598ae8fad666d9b012c8ed2b79a236ec4",
				"e9a66845e05d5abc0ad04ec80f774a7e585c6e8db975962d069a522137b80c1d",
			},
			"f3e94742aca4b5ef85488dc37c06c3282295ffec960994b2c0d5ac2a25a95766",
		},
		{
			[]string {
				"4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b",
			},
			"4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b",
		},
		{
			[]string {
				"ef1d870d24c85b89d92ad50f4631026f585d6a34e972eaf427475e5d60acf3a3",
				"f9fc751cb7dc372406a9f8d738d5e6f8f63bab71986a39cf36ee70ee17036d07",
				"db60fb93d736894ed0b86cb92548920a3fe8310dd19b0da7ad97e48725e1e12e",
				"220ebc64e21abece964927322cba69180ed853bb187fbc6923bac7d010b9d87a",
				"71b3dbaca67e9f9189dad3617138c19725ab541ef0b49c05a94913e9f28e3f4e",
				"fe305e1ed08212d76161d853222048eea1f34af42ea0e197896a269fbf8dc2e0",
				"21d2eb195736af2a40d42107e6abd59c97eb6cffd4a5a7a7709e86590ae61987",
				"dd1fd2a6fc16404faf339881a90adbde7f4f728691ac62e8f168809cdfae1053",
				"74d681e0e03bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20",
			},
			"2fda58e5959b0ee53c5253da9b9f3c0c739422ae04946966991cf55895287552",
		},
	}

	for _, oneCase := range testcases {
		var got *MerkleNode
		var err error
		if got,err = ConstructMerkleRoot(oneCase.txids); err != nil {
			t.Error(err)
			return
		}
		if got.Value != oneCase.merkleRoot {
			t.Error("construct merkle root error")
			t.Error("want: ", oneCase.merkleRoot)
			t.Error("got: ", got.Value)
			return
		}
	}
}

 

这里的测试数据都来自真实比特币主网区块数据，可自行添加测试用例

 

（全文完）

 

参考资料：

https://learnmeabitcoin.com/guide/merkle-root