Example #1
0
func (b *blockchain) verifyTransaction(m message.NamecoinTransaction) bool {
	blck, ok := b.Direct[m.BlockId]
	if !ok {
		fmt.Println(m.BlockId, "not in blockchain.")
		return false
	}

	var hashes []wire.ShaHash
	for _, v := range m.VerificationHashes {
		temp, err := wire.NewShaHash(v)
		if err != nil {
			fmt.Println("Unable to create Verification Sha hash", err)
			return false
		}

		hashes = append(hashes, *temp)
	}

	txHash, err := wire.NewShaHashFromStr(m.TxId)
	if err != nil {
		fmt.Println("Cannot make TX Sha Hash", err)
		return false
	}

	_, err = VerifyMerkleBranch(wire.MerkleBranch{
		BranchSideMask: m.Branch,
		BranchHash:     hashes,
	}, &blck.MerkleRoot, txHash)
	if err != nil {
		fmt.Println("Error verifying Merkle Branch", err)
	}

	return err == nil
}
Example #2
0
// constructMerkleTree will create a wire.MerkleBranch object that places the
// transaction in the block Merkle Tree.
func constructMerkleTree(transactions []string, root string, transaction string) (wire.MerkleBranch, error) {
	workingRow := make([]*wire.ShaHash, len(transactions))

	// Used to build the Merkle Branch
	var (
		currentTransaction int
		verificationHashes []wire.ShaHash
		height             uint32
		merkleBitmask      int32
	)

	var err error

	for i, v := range transactions {
		if v == transaction {
			currentTransaction = i
		}

		if workingRow[i], err = wire.NewShaHashFromStr(v); err != nil {
			return wire.MerkleBranch{}, err
		}
	}

	for {
		// We double the last entry if the row has an odd number of
		if len(workingRow)%2 == 1 {
			workingRow = append(workingRow, workingRow[len(workingRow)-1])
		}

		// Hash into the Next Row
		var nextRow []*wire.ShaHash
		for i := 0; i < len(workingRow); i += 2 {
			left := workingRow[i]
			right := workingRow[i+1]

			if currentTransaction == i {
				// We need to add the right hash to the merkle branch.
				verificationHashes = append(verificationHashes, *right)
				currentTransaction = len(nextRow)
				merkleBitmask = merkleBitmask | (0 << height)
			} else if currentTransaction == i+1 {
				// We need to add the left hash to the merkle branch.
				verificationHashes = append(verificationHashes, *left)
				currentTransaction = len(nextRow)
				merkleBitmask = merkleBitmask | (1 << height)
			}

			hash, err := wire.NewShaHash(wire.DoubleSha256(
				append(left.Bytes(), right.Bytes()...),
			))
			if err != nil {
				return wire.MerkleBranch{}, err
			}

			nextRow = append(nextRow, hash)
		}

		if len(nextRow) == 1 {
			if nextRow[0].String() != root {
				return wire.MerkleBranch{}, errors.New("Cannot validate MerkleTree.")
			}

			break
		}

		workingRow = nextRow
		height++
	}

	return wire.MerkleBranch{
		BranchHash:     verificationHashes,
		BranchSideMask: merkleBitmask,
	}, nil
}