func TestTransactionSignInputs(t *testing.T) {
tx := &Transaction{}
// Panics if txns already signed
tx.Sigs = append(tx.Sigs, cipher.Sig{})
assert.Panics(t, func() { tx.SignInputs([]cipher.SecKey{}) })
// Panics if not enough keys
tx = &Transaction{}
ux, s := makeUxOutWithSecret(t)
tx.PushInput(ux.Hash())
ux2, s2 := makeUxOutWithSecret(t)
tx.PushInput(ux2.Hash())
tx.PushOutput(makeAddress(), 40, 80)
assert.Equal(t, len(tx.Sigs), 0)
assert.Panics(t, func() { tx.SignInputs([]cipher.SecKey{s}) })
assert.Equal(t, len(tx.Sigs), 0)
// Valid signing
h := tx.HashInner()
assert.NotPanics(t, func() { tx.SignInputs([]cipher.SecKey{s, s2}) })
assert.Equal(t, len(tx.Sigs), 2)
assert.Equal(t, tx.HashInner(), h)
p := cipher.PubKeyFromSecKey(s)
a := cipher.AddressFromPubKey(p)
p = cipher.PubKeyFromSecKey(s2)
a2 := cipher.AddressFromPubKey(p)
assert.Nil(t, cipher.ChkSig(a, cipher.AddSHA256(h, tx.In[0]), tx.Sigs[0]))
assert.Nil(t, cipher.ChkSig(a2, cipher.AddSHA256(h, tx.In[1]), tx.Sigs[1]))
assert.NotNil(t, cipher.ChkSig(a, h, tx.Sigs[1]))
assert.NotNil(t, cipher.ChkSig(a2, h, tx.Sigs[0]))
}
func makeTransactionForChainWithHoursFee(t *testing.T, bc *Blockchain,
ux coin.UxOut, sec cipher.SecKey, hours, fee uint64) (coin.Transaction, cipher.SecKey) {
chrs := ux.CoinHours(bc.Time())
if chrs < hours+fee {
log.Panicf("CoinHours underflow. Have %d, need at least %d", chrs,
hours+fee)
}
assert.Equal(t, cipher.AddressFromPubKey(cipher.PubKeyFromSecKey(sec)), ux.Body.Address)
knownUx, exists := bc.GetUnspent().Get(ux.Hash())
assert.True(t, exists)
assert.Equal(t, knownUx, ux)
tx := coin.Transaction{}
tx.PushInput(ux.Hash())
p, newSec := cipher.GenerateKeyPair()
addr := cipher.AddressFromPubKey(p)
tx.PushOutput(addr, 1e6, hours)
coinsOut := ux.Body.Coins - 1e6
if coinsOut > 0 {
tx.PushOutput(genAddress, coinsOut, chrs-hours-fee)
}
tx.SignInputs([]cipher.SecKey{sec})
assert.Equal(t, len(tx.Sigs), 1)
assert.Nil(t, cipher.ChkSig(ux.Body.Address, cipher.AddSHA256(tx.HashInner(), tx.In[0]), tx.Sigs[0]))
tx.UpdateHeader()
assert.Nil(t, tx.Verify())
err := bc.VerifyTransaction(tx)
assert.Nil(t, err)
return tx, newSec
}
// Validates the inputs to a transaction by checking signatures. Assumes txn
// has valid number of signatures for inputs.
func verifyTransactionInputs(tx Transaction, uxIn UxArray) error {
if DebugLevel2 {
if len(tx.In) != len(tx.Sigs) || len(tx.In) != len(uxIn) {
log.Panic("tx.In != tx.Sigs != uxIn")
}
if tx.InnerHash != tx.HashInner() {
log.Panic("Invalid Tx Header Hash")
}
}
// Check signatures against unspent address
for i, _ := range tx.In {
hash := cipher.AddSHA256(tx.InnerHash, tx.In[i]) //use inner hash, not outer hash
err := cipher.ChkSig(uxIn[i].Body.Address, hash, tx.Sigs[i])
if err != nil {
return errors.New("Signature not valid for output being spent")
}
}
if DebugLevel2 {
// Check that hashes match.
// This would imply a bug with UnspentPool.GetMultiple
if len(tx.In) != len(uxIn) {
log.Panic("tx.In does not match uxIn")
}
for i, _ := range tx.In {
if tx.In[i] != uxIn[i].Hash() {
log.Panic("impossible error: Ux hash mismatch")
}
}
}
return nil
}
// Returns unspent output checksum for the Block. Must be called after Block
// is fully initialized, and before its outputs are added to the unspent pool
func getSnapshotHash(unspent UnspentPool, prevHash cipher.SHA256) [4]byte {
uxHash := cipher.AddSHA256(unspent.XorHash, prevHash)
var snapshot [4]byte
if copy(snapshot[:], uxHash[:]) != 4 {
log.Panic("UxSnapshot copy is broken")
}
return snapshot
}
// Compares the state of the current UxSnapshot hash to state of unspent
// output pool.
func (self *Blockchain) verifyUxSnapshot(b Block) error {
head := self.Head().Head
uxHash := cipher.AddSHA256(self.Unspent.XorHash, head.Hash())
if !bytes.Equal(b.Head.UxSnapshot[:], uxHash[:4]) {
return errors.New("UxSnapshot does not match")
}
return nil
}
func TestGetUxSnapshot(t *testing.T) {
unsp := NewUnspentPool()
xor := randSHA256(t)
unsp.XorHash = xor
prev := randSHA256(t)
sh := getSnapshotHash(unsp, prev)
expect := cipher.AddSHA256(xor, prev)
assert.True(t, bytes.Equal(expect[:4], sh[:]))
assert.NotEqual(t, sh, [4]byte{})
}
func TestVerifyUxSnapshot(t *testing.T) {
bc := NewBlockchain()
gb := bc.CreateGenesisBlock(genAddress, _genTime, _genCoins)
b := Block{Body: BlockBody{}, Head: BlockHeader{}}
b.Body.Transactions = append(b.Body.Transactions, makeTransaction(t))
bc.Unspent.XorHash = randSHA256(t)
uxHash := cipher.AddSHA256(bc.Unspent.XorHash, gb.Head.Hash())
copy(b.Head.UxSnapshot[:], uxHash[:])
assert.Nil(t, bc.verifyUxSnapshot(b))
b.Head.UxSnapshot = [4]byte{}
assertError(t, bc.verifyUxSnapshot(b), "UxSnapshot does not match")
}
// Signs all inputs in the transaction
func (self *Transaction) SignInputs(keys []cipher.SecKey) {
self.InnerHash = self.HashInner() //update hash
if len(self.Sigs) != 0 {
log.Panic("Transaction has been signed")
}
if len(keys) != len(self.In) {
log.Panic("Invalid number of keys")
}
if len(keys) > math.MaxUint16 {
log.Panic("Too many key")
}
if len(keys) == 0 {
log.Panic("No keys")
}
sigs := make([]cipher.Sig, len(self.In))
inner_hash := self.HashInner()
for i, k := range keys {
h := cipher.AddSHA256(inner_hash, self.In[i]) //hash to sign
sigs[i] = cipher.SignHash(h, k)
}
self.Sigs = sigs
}
// Verify attempts to determine if the transaction is well formed
// Verify cannot check transaction signatures, it needs the address from unspents
// Verify cannot check if outputs being spent exist
// Verify cannot check if the transaction would create or destroy coins
// or if the inputs have the required coin base
func (self *Transaction) Verify() error {
h := self.HashInner()
if h != self.InnerHash {
return errors.New("Invalid header hash")
}
if len(self.In) == 0 {
return errors.New("No inputs")
}
if len(self.Out) == 0 {
return errors.New("No outputs")
}
// Check signature index fields
if len(self.Sigs) != len(self.In) {
return errors.New("Invalid number of signatures")
}
if len(self.Sigs) >= math.MaxUint16 {
return errors.New("Too many signatures and inputs")
}
// Check duplicate inputs
uxOuts := make(map[cipher.SHA256]int, len(self.In))
for i, _ := range self.In {
uxOuts[self.In[i]] = 1
}
if len(uxOuts) != len(self.In) {
return errors.New("Duplicate spend")
}
if self.Type != 0 {
return errors.New("transaction type invalid")
}
if self.Length != uint32(self.Size()) {
return errors.New("transaction size prefix invalid")
}
// Check for duplicate potential outputs
outputs := make(map[cipher.SHA256]int, len(self.Out))
uxb := UxBody{
SrcTransaction: self.Hash(),
}
for _, to := range self.Out {
uxb.Coins = to.Coins
uxb.Hours = to.Hours
uxb.Address = to.Address
outputs[uxb.Hash()] = 1
}
if len(outputs) != len(self.Out) {
return errors.New("Duplicate output in transaction")
}
// Validate signature
for i, sig := range self.Sigs {
hash := cipher.AddSHA256(self.InnerHash, self.In[i])
if err := cipher.VerifySignedHash(sig, hash); err != nil {
return err
}
}
// Artificial restriction to prevent spam
// Must spend only multiples of 1e6
for _, txo := range self.Out {
if txo.Coins == 0 {
return errors.New("Zero coin output")
}
if txo.Coins%1e6 != 0 {
return errors.New("Transaction outputs must be multiple of 1e6 " +
"base units")
}
}
return nil
}