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
}
// 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
}