From 79e120df4858f98bdea4731a951af833428f8247 Mon Sep 17 00:00:00 2001
From: liweixia <790890362@qq.com>
Date: Thu, 3 Jun 2021 11:50:14 +0800
Subject: [PATCH] feat: add hpc validator

---
 go.mod                                   |  1 +
 validator/validatorlib/hpc_validation.go | 92 ++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 validator/validatorlib/hpc_validation.go

diff --git a/go.mod b/go.mod
index 8497311..3c50ebf 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.13
 
 require (
 	github.com/Shopify/sarama v1.27.0 // indirect
+	github.com/cbergoon/merkletree v0.2.0
 	github.com/gogo/protobuf v1.3.2
 	github.com/golang/mock v1.4.3
 	github.com/hashicorp/go-version v1.2.1 // indirect
diff --git a/validator/validatorlib/hpc_validation.go b/validator/validatorlib/hpc_validation.go
new file mode 100644
index 0000000..1eabe6a
--- /dev/null
+++ b/validator/validatorlib/hpc_validation.go
@@ -0,0 +1,92 @@
+package validatorlib
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/json"
+
+	"github.com/cbergoon/merkletree"
+	"github.com/meshplus/bitxhub-kit/crypto"
+	"github.com/meshplus/bitxhub-kit/crypto/asym"
+	"github.com/meshplus/bitxhub-kit/types"
+)
+
+type HpcProof struct {
+	Signatures [][]byte `json:"signatures"`
+	SpvHash    []byte   `json:"spv_hash"`
+	PreHashes  [][]byte `json:"pre_hashes"`
+	PostHashes [][]byte `json:"post_hashes"`
+	RootHash   []byte   `json:"root_hash"`
+}
+
+type HpcValidator struct {
+	Total      int      `json:"total"`
+	Validators [][]byte `json:"validators"`
+}
+
+func ValidateHpc(proof []byte, validators []byte, payload []byte) (bool, error) {
+	hpcProof := &HpcProof{}
+	hpcValidator := &HpcValidator{}
+	if err := json.Unmarshal(proof, hpcProof); err != nil {
+		return false, err
+	}
+	if err := json.Unmarshal(validators, hpcValidator); err != nil {
+		return false, err
+	}
+	count := 0
+	for _, sig := range hpcProof.Signatures {
+		validSig := false
+		for index, validator := range hpcValidator.Validators {
+			address := types.NewAddress(validator)
+			ok, err := asym.Verify(crypto.Secp256k1, sig, hpcProof.SpvHash, *address)
+			if err != nil {
+				return false, err
+			}
+			if ok {
+				validSig = true
+				hpcValidator.Validators = append(hpcValidator.Validators[:index], hpcValidator.Validators[index+1:]...)
+				break
+			}
+		}
+		if validSig {
+			count += 1
+			if count == (hpcValidator.Total-1)/3+1 {
+				return VerifyMerkle(hpcProof, payload)
+			}
+		}
+	}
+	return false, nil
+}
+
+func VerifyMerkle(hpcProof *HpcProof, payload []byte) (bool, error) {
+	h := sha256.Sum256(payload)
+	if !bytes.Equal(h[:], hpcProof.SpvHash) {
+		return false, nil
+	}
+	hashes := make([]merkletree.Content, 0, len(hpcProof.PreHashes)+len(hpcProof.PostHashes)+1)
+	for _, hash := range hpcProof.PreHashes {
+		hashes = append(hashes, types.NewHash(hash))
+	}
+	hashes = append(hashes, types.NewHash(hpcProof.SpvHash))
+	for _, hash := range hpcProof.PostHashes {
+		hashes = append(hashes, types.NewHash(hash))
+	}
+	root, err := calcMerkleRoot(hashes)
+	if err != nil {
+		return false, err
+	}
+	return root.Equals(types.NewHash(hpcProof.RootHash))
+}
+
+func calcMerkleRoot(contents []merkletree.Content) (*types.Hash, error) {
+	if len(contents) == 0 {
+		return &types.Hash{}, nil
+	}
+
+	tree, err := merkletree.NewTree(contents)
+	if err != nil {
+		return nil, err
+	}
+
+	return types.NewHash(tree.MerkleRoot()), nil
+}