// generateFund is the high-level logic for funding any P2SH address with the 'go-bitcoin-multisig fund' subcommand.
// Takes flagPrivateKey (private key of input Bitcoins to fund with), flagInputTx (input transaction hash of
// Bitcoins to fund with), flagAmount (amount in Satoshis to send, with balance left over from input being used
// as transaction fee) and flagP2SHDestination (destination P2SH multisig address which is being funded) as arguments.
func generateFund(flagPrivateKey string, flagInputTx string, flagAmount int, flagP2SHDestination string) string {
//Get private key as decoded raw bytes
privateKey := base58check.Decode(flagPrivateKey)
//In order to construct the raw transaction we need the input transaction hash,
//the P2SH destination address, the number of satoshis to send, and the scriptSig
//which is temporarily (prior to signing) the ScriptPubKey of the input transaction.
publicKey, err := btcutils.NewPublicKey(privateKey)
if err != nil {
log.Fatal(err)
}
publicKeyHash, err := btcutils.Hash160(publicKey)
if err != nil {
log.Fatal(err)
}
tempScriptSig, err := btcutils.NewP2PKHScriptPubKey(publicKeyHash)
if err != nil {
log.Fatal(err)
}
redeemScriptHash := base58check.Decode(flagP2SHDestination)
//Create our scriptPubKey
scriptPubKey, err := btcutils.NewP2SHScriptPubKey(redeemScriptHash)
if err != nil {
log.Fatal(err)
}
//Create unsigned raw transaction
rawTransaction, err := btcutils.NewRawTransaction(flagInputTx, flagAmount, tempScriptSig, scriptPubKey)
if err != nil {
log.Fatal(err)
}
//After completing the raw transaction, we append
//SIGHASH_ALL in little-endian format to the end of the raw transaction.
hashCodeType, err := hex.DecodeString("01000000")
if err != nil {
log.Fatal(err)
}
var rawTransactionBuffer bytes.Buffer
rawTransactionBuffer.Write(rawTransaction)
rawTransactionBuffer.Write(hashCodeType)
rawTransactionWithHashCodeType := rawTransactionBuffer.Bytes()
//Sign the raw transaction, and output it to the console.
finalTransaction, err := signP2PKHTransaction(rawTransactionWithHashCodeType, privateKey, scriptPubKey, flagInputTx, flagAmount)
if err != nil {
log.Fatal(err)
}
finalTransactionHex := hex.EncodeToString(finalTransaction)
return finalTransactionHex
}
// signP2PKHTransaction signs a raw P2PKH transaction, given a private key and the scriptPubKey, inputTx and amount
// to construct the final transaction.
func signP2PKHTransaction(rawTransaction []byte, privateKey []byte, scriptPubKey []byte, inputTx string, amount int) ([]byte, error) {
publicKey, err := btcutils.NewPublicKey(privateKey)
if err != nil {
return nil, err
}
signature, err := btcutils.NewSignature(rawTransaction, privateKey)
if err != nil {
return nil, err
}
hashCodeType, err := hex.DecodeString("01")
if err != nil {
return nil, err
}
//signatureLength is +1 to add hashCodeType
signatureLength := byte(len(signature) + 1)
//Create scriptSig
var buffer bytes.Buffer
buffer.WriteByte(signatureLength)
buffer.Write(signature)
buffer.WriteByte(hashCodeType[0])
buffer.WriteByte(byte(len(publicKey)))
buffer.Write(publicKey)
scriptSig := buffer.Bytes()
//Finally create transaction with actual scriptSig
signedRawTransaction, err := btcutils.NewRawTransaction(inputTx, amount, scriptSig, scriptPubKey)
if err != nil {
return nil, err
}
return signedRawTransaction, nil
}
// generateKeys is the high-level logic for generating public/private key pairs with the 'go-bitcoin-multisig keys' subcommand.
// Takes flagCount (desired number of key pairs) and flagConcise (true hides warnings and helpful messages for conciseness)
// as arguments.
func generateKeys(flagKeyCount int) ([]string, []string, []string) {
publicKeyHexs := make([]string, flagKeyCount)
publicAddresses := make([]string, flagKeyCount)
privateKeyWIFs := make([]string, flagKeyCount)
for i := 0; i <= flagKeyCount-1; i++ {
//Generate private key
privateKey := btcutils.NewPrivateKey()
//Generate public key from private key
publicKey, err := btcutils.NewPublicKey(privateKey)
if err != nil {
log.Fatal(err)
}
//Get hex encoded version of public key
publicKeyHexs[i] = hex.EncodeToString(publicKey)
//Get public address by hashing with SHA256 and RIPEMD160 and base58 encoding with mainnet prefix 00
publicKeyHash, err := btcutils.Hash160(publicKey)
if err != nil {
log.Fatal(err)
}
publicAddresses[i] = base58check.Encode("00", publicKeyHash)
//Get private key in Wallet Import Format (WIF) by base58 encoding with prefix 80
privateKeyWIFs[i] = base58check.Encode("80", privateKey)
}
return privateKeyWIFs, publicKeyHexs, publicAddresses
}