Implement transactions signing and verification

This commit is contained in:
Ivan Kuznetsov 2017-09-10 10:34:39 +07:00
parent 7e8c88867d
commit 2ce04f8f59
2 changed files with 74 additions and 4 deletions

View File

@ -1,7 +1,10 @@
package main
import (
"bytes"
"crypto/ecdsa"
"encoding/hex"
"errors"
"fmt"
"log"
"os"
@ -29,6 +32,12 @@ type BlockchainIterator struct {
func (bc *Blockchain) MineBlock(transactions []*Transaction) {
var lastHash []byte
for _, tx := range transactions {
if bc.VerifyTransaction(tx) != true {
log.Panic("ERROR: Invalid transaction")
}
}
err := bc.db.View(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte(blocksBucket))
lastHash = b.Get([]byte("l"))
@ -60,6 +69,63 @@ func (bc *Blockchain) MineBlock(transactions []*Transaction) {
})
}
// FindTransaction finds a transaction by its ID
func (bc *Blockchain) FindTransaction(ID []byte) (Transaction, error) {
bci := bc.Iterator()
for {
block := bci.Next()
for _, tx := range block.Transactions {
if bytes.Compare(tx.ID, ID) == 0 {
return *tx, nil
}
}
if len(block.PrevBlockHash) == 0 {
break
}
}
return Transaction{}, errors.New("Transaction is not found")
}
// SignTransaction signs a Transaction
func (bc *Blockchain) SignTransaction(tx *Transaction, privKey ecdsa.PrivateKey) {
prevTXs := make(map[string]Transaction)
for _, vin := range tx.Vin {
prevTX, err := bc.FindTransaction(vin.Txid)
if err != nil {
log.Panic(err)
}
prevTXs[hex.EncodeToString(prevTX.ID)] = prevTX
}
tx.Sign(privKey, prevTXs)
}
// VerifyTransaction verifies transaction
func (bc *Blockchain) VerifyTransaction(tx *Transaction) bool {
prevTXs := make(map[string]Transaction)
for _, vin := range tx.Vin {
prevTX, err := bc.FindTransaction(vin.Txid)
if err != nil {
log.Panic(err)
}
prevTXs[hex.EncodeToString(prevTX.ID)] = prevTX
}
for _, tx := range prevTXs {
fmt.Println(tx)
}
// fmt.Println()
// fmt.Println(tx)
return tx.Verify(prevTXs)
}
// FindUnspentTransactions returns a list of transactions containing unspent outputs
func (bc *Blockchain) FindUnspentTransactions(pubKeyHash []byte) []Transaction {
var unspentTXs []Transaction

View File

@ -36,6 +36,7 @@ func (tx Transaction) String() string {
lines = append(lines, fmt.Sprintf("Transaction %x:", tx.ID))
for i, input := range tx.Vin {
lines = append(lines, fmt.Sprintf(" Input %d:", i))
lines = append(lines, fmt.Sprintf(" TXID: %x", input.Txid))
lines = append(lines, fmt.Sprintf(" Out: %d", input.Vout))
@ -84,13 +85,13 @@ func (tx *Transaction) TrimmedCopy() Transaction {
}
// Sign signs each input of a Transaction
func (tx *Transaction) Sign(privKey ecdsa.PrivateKey, prevTx *Transaction) {
func (tx *Transaction) Sign(privKey ecdsa.PrivateKey, prevTXs map[string]Transaction) {
if tx.IsCoinbase() {
return
}
for _, vin := range tx.Vin {
if bytes.Compare(vin.Txid, prevTx.ID) != 0 {
if prevTXs[hex.EncodeToString(vin.Txid)].ID == nil {
log.Panic("ERROR: Previous transaction is not correct")
}
}
@ -98,6 +99,7 @@ func (tx *Transaction) Sign(privKey ecdsa.PrivateKey, prevTx *Transaction) {
txCopy := tx.TrimmedCopy()
for inID, vin := range txCopy.Vin {
prevTx := prevTXs[hex.EncodeToString(vin.Txid)]
txCopy.Vin[inID].ScriptSig = prevTx.Vout[vin.Vout].ScriptPubKey
txCopy.SetID()
txCopy.Vin[inID].ScriptSig = []byte{}
@ -113,7 +115,7 @@ func (tx *Transaction) Sign(privKey ecdsa.PrivateKey, prevTx *Transaction) {
}
// Verify verifies signatures of Transaction inputs
func (tx *Transaction) Verify(prevTx *Transaction) bool {
func (tx *Transaction) Verify(prevTXs map[string]Transaction) bool {
sigLen := 64
if tx.IsCoinbase() {
@ -121,7 +123,7 @@ func (tx *Transaction) Verify(prevTx *Transaction) bool {
}
for _, vin := range tx.Vin {
if bytes.Compare(vin.Txid, prevTx.ID) != 0 {
if prevTXs[hex.EncodeToString(vin.Txid)].ID == nil {
log.Panic("ERROR: Previous transaction is not correct")
}
}
@ -130,6 +132,7 @@ func (tx *Transaction) Verify(prevTx *Transaction) bool {
curve := elliptic.P256()
for inID, vin := range tx.Vin {
prevTx := prevTXs[hex.EncodeToString(vin.Txid)]
txCopy.Vin[inID].ScriptSig = prevTx.Vout[vin.Vout].ScriptPubKey
txCopy.SetID()
txCopy.Vin[inID].ScriptSig = []byte{}
@ -249,6 +252,7 @@ func NewUTXOTransaction(from, to string, amount int, bc *Blockchain) *Transactio
tx := Transaction{nil, inputs, outputs}
tx.SetID()
bc.SignTransaction(&tx, wallet.PrivateKey)
return &tx
}