func (inv *Inventory) VerifyTransaction(tx *messages.Transaction) (bool, error) {
var inputValue, outputValue uint64
for index, input := range tx.Inputs {
stack := script.Stack{}
err := stack.Execute(input.Signature, nil)
if err != nil {
return false, fmt.Errorf("Failed to push signature: %v", err)
}
prev := input.PreviousOutput
d, found := inv.txHashes[string(prev.Hash)]
if !found {
return false, fmt.Errorf("Input tx %x not found in map.", prev.Hash)
}
inputTx := d.tx
output := inputTx.Outputs[prev.Index]
inputValue += output.Value
data := &script.Data{
Hasher: func(c uint32) []byte {
return utils.DoubleHash(tx.SignSerialize(
index, output.Script, c))
}}
err = stack.Execute(output.Script, data)
if err != nil {
return false, fmt.Errorf("Failed to execute script: %v", err)
}
if !stack.CheckSuccess() {
return false, fmt.Errorf("Signature on input %d not valid.", index)
}
}
for _, output := range tx.Outputs {
outputValue += output.Value
}
if outputValue > inputValue {
return false, fmt.Errorf("Outputs have higher value (%d) than inputs (%d).",
outputValue, inputValue)
}
return true, nil
}
