merkletree

go-merkletree

The mht implemented for the podr2 algorithm can find the auxiliary nodes through several leaf nodes. mht root can be restored using leaf nodes and auxiliary nodes

package main

import (
	"crypto/sha256"
	"encoding/hex"
	"github.com/CESSProject/go-merkletree"
	"log"
)

//TestContent implements the Content interface provided by merkletree and represents the content stored in the tree.
type TestContent struct {
	x string
}

//CalculateHash hashes the values of a TestContent
func (t TestContent) CalculateHash() ([]byte, error) {
	h := sha256.New()
	if _, err := h.Write([]byte(t.x)); err != nil {
		return nil, err
	}

	return h.Sum(nil), nil
}

//Equals tests for equality of two Contents
func (t TestContent) Equals(other merkletree.Content) (bool, error) {
	return t.x == other.(TestContent).x, nil
}

func main() {
	//Build list of Content to build tree
	var list []merkletree.Content
	list = append(list, TestContent{x: "Dog"})
	list = append(list, TestContent{x: "Cat"})
	list = append(list, TestContent{x: "Bird"})
	list = append(list, TestContent{x: "Panda"})
	list = append(list, TestContent{x: "Wolf"})
	list = append(list, TestContent{x: "Dolphin"})
	list = append(list, TestContent{x: "Geoduck"})
	list = append(list, TestContent{x: "Eagle"})
	list = append(list, TestContent{x: "Giraffe"})
	//Create a new Merkle Tree from the list of Content
	t, err := merkletree.NewTree(list)
	if err != nil {
		log.Fatal(err)
	}

	//The index of the incoming leaf node.
	testLeafs := []int64{0,9}
	_, nodeMap, nodes, _ := t.GetMerkleAuxiliaryNode(merkletree.GetContentMap(testLeafs))

	for k := 0; k < len(nodes); k++ {
		log.Printf(" merkle path , %v is %s ,nodes location is:(%v;%v)\n", k, hex.EncodeToString(nodes[k].Hash), nodes[k].Height, nodes[k].Index)
	}

	//Get the structure of the reconstructed node, the incoming leaf node and its auxiliary node.
	ProofList,err:=t.RebuildNodeListWithTree(nodeMap,testLeafs)
	if err!=nil{
		log.Fatal(err)
	}

	//rebuild tree ,get root node
	root,err:=merkletree.NewTreeWithAuxiliaryNode(ProofList,sha256.New)
	log.Println("Rebuild MHT ROOT Hash is:", hex.EncodeToString(root.Hash))

	//Get the Merkle Root of the tree.
	mr := t.MerkleRoot()
	log.Println("MHT ROOT Hash is:", hex.EncodeToString(mr))

	//String representation
	log.Println(t)
}