gocoin

README

GOcoin

Overview

A fork of https://github.com/utamaro/gocoin

This is a library to make bitcoin address and transactions which was initially forked from hellobitcoin, and added some useful features.

GOcoin uses btcec library in btcd instead of https://github.com/toxeus/go-secp256k1 to make it a pure GO program.

Features

1. Normaly Payment(P2PKH) supporting multi TxIns and multi TxOuts.
2. Gethering unspent transaction outputs(UTXO) and send transactions by using Blockr.io WEB API.
3. M of N multisig whose codes were partially ported from https://github.com/soroushjp/go-bitcoin-multisig.

Changes

1. Removed the "local" package btcec and changed the code to use github.com/btcsuite/btcd/btcec
2. Refactored a lot of code
3. Implements dynamic fee calculation using the API from 21.co

Requirements

This requires

• git
• go 1.5+

Installation

$ mkdir -p tmp/{src,bin,pkg}
$ cd tmp
$ export GOPATH=$(pwd)
$ go get github.com/klim8d/gocoin

Example

(This example omits error handlings for simplicity.)

Key Handling

import gocoin

func main(){
	//make a public and private key pair.
	key, _ := gocoin.GenerateKey(true)
	adr, _ := key.Pub.GetAddress()
	fmt.Println("address=", adr)
	wif := key.Priv.GetWIFAddress()
	fmt.Println("wif=", wif)
	
	//get key from wif
	wif := "928Qr9J5oAC6AYieWJ3fG3dZDjuC7BFVUqgu4GsvRVpoXiTaJJf"
	txKey, _ := gocoin.GetKeyFromWIF(wif)
}

Normal Payment

import gocoin

func main(){
	key, _ := gocoin.GenerateKey(true)

	//get unspent transactions
	service := gocoin.NewBlockrService(true)
	txs, _ := service.GetUTXO(adr,nil)
	
	//Normal Payment
	gocoin.Pay([]*Key{txKey}, []*gocoin.Amounts{&{gocoin.Amounts{"n2eMqTT929pb1RDNuqEnxdaLau1rxy3efi", 0.01*gocoin.BTC}}, service)
}

M of N Multisig

import gocoin

func main(){
	key, _ := gocoin.GenerateKey(true)
	service := gocoin.NewBlockrService(true)

	//2 of 3 multisig
	key1, _ := gocoin.GenerateKey(true)
	key2, _ := gocoin.GenerateKey(true)
	key3, _ := gocoin.GenerateKey(true)
	rs, _:= gocoin.NewRedeemScript(2, []*PublicKey{key1.Pub, key2.Pub, key3.Pub})
	//make a fund
	rs.Pay([]*Key{txKey}, 0.05*gocoin.BTC, service)

    //get a raw transaction for signing.
	rawtx, tx, _:= rs.CreateRawTransactionHashed([]*gocoin.Amounts{&{gocoin.Amounts{"n3Bp1hbgtmwDtjQTpa6BnPPCA8fTymsiZy", 0.05*gocoin.BTC}}, service)

	//spend the fund
	sign1, _:= key2.Priv.Sign(rawtx)
	sign2, _:= key3.Priv.Sign(rawtx)
	rs.Spend(tx, [][]byte{nil, sign1, sign2}, service)
}

Contribution

Improvements to the codebase and pull requests are encouraged.

Documentation

Index

• Constants
• Variables
• func IsTestnet(addr string) (bool, error)
• func Pay(keys []*Key, addresses []*Amounts, service Service) ([]byte, error)
• func SetLogger(logger *log.Logger)
• func SetUTXOSpent(hash []byte)
• type Amounts
• type BlockrService
  • func (b *BlockrService) GetServiceName() string
  • func (b *BlockrService) GetUTXO(addr string, key *Key) (UTXOs, error)
  • func (b *BlockrService) SendTX(data []byte) ([]byte, error)
• type Key
  • func GenerateKey(flagTestnet bool) (*Key, error)
  • func GetKeyFromWIF(wif string) (*Key, error)
  • func (key *Key) SignMessage(hash []byte) ([]byte, error)
• type PrivateKey
  • func (priv *PrivateKey) GetWIFAddress() string
  • func (priv *PrivateKey) Sign(hash []byte) ([]byte, error)
• type PublicKey
  • func GetPublicKey(pubKeyByte []byte, isTestnet bool) (*PublicKey, error)
  • func (pub *PublicKey) GetAddress() (string, []byte)
• type RedeemScript
  • func NewRedeemScript(m int, publicKeys []*PublicKey) (*RedeemScript, error)
  • func (rs *RedeemScript) CreateRawTransactionHashed(addresses []*Amounts, service Service) ([]byte, *TX, error)
  • func (rs *RedeemScript) GetAddress() string
  • func (rs *RedeemScript) Pay(keys []*Key, amount uint64, service Service) ([]byte, error)
  • func (rs *RedeemScript) Spend(tx *TX, signs [][]byte, service Service) ([]byte, error)
• type Service
  • func NewBlockrService() (Service, error)
  • func NewBlockrServiceForTest() (Service, error)
  • func SelectService(isTestnet bool) (Service, error)
• type TX
  • func (tx *TX) MakeTX() ([]byte, error)
• type TXin
• type TXout
• type UTXO
• type UTXOs
  • func (us UTXOs) Len() int
  • func (us UTXOs) Less(i, j int) bool
  • func (us UTXOs) Swap(i, j int)

Constants

const (

	//BTC is unit to convert BTC to satoshi
	BTC = 100000000 //100 million

	//Fee for a transaction
	DefaultFee = uint64(0.0001 * BTC) //  0.0001 BTC/kB
)

Variables

var Services = []func() (Service, error){
	NewBlockrService,
}

TestServices is an array containing generator of Services

var TestServices = []func() (Service, error){
	NewBlockrServiceForTest,
}

TestServices is an array containing generator of Services for testnet

Functions

func IsTestnet

func IsTestnet(addr string) (bool, error)

IsTestnet returns true if addr is for testnet.

func Pay

func Pay(keys []*Key, addresses []*Amounts, service Service) ([]byte, error)

Pay pays in a nomal way.(P2KSH)

func SetLogger

func SetLogger(logger *log.Logger)

SetLogger sets logger this module uses.

func SetUTXOSpent

func SetUTXOSpent(hash []byte)

SetTXSpent sets tx hash is already spent.

Types

type Amounts

type Amounts struct {
	Address string
	Amount  uint64
}

Amounts represents amount of bitcoin of address

type BlockrService

type BlockrService struct {
	// contains filtered or unexported fields
}

BlockrService is a service using Blockr.io.

func (*BlockrService) GetServiceName

func (b *BlockrService) GetServiceName() string

GetServiceName return service name.

func (*BlockrService) GetUTXO

func (b *BlockrService) GetUTXO(addr string, key *Key) (UTXOs, error)

GetUTXO gets unspent transaction outputs by using Blockr.io.

func (*BlockrService) SendTX

func (b *BlockrService) SendTX(data []byte) ([]byte, error)

SendTX send a transaction using Blockr.io.

type Key

type Key struct {
	Pub  *PublicKey
	Priv *PrivateKey
}

Key includes PublicKey and PrivateKey.

func GenerateKey

func GenerateKey(flagTestnet bool) (*Key, error)

GenerateKey generates random PublicKey and PrivateKey.

func GetKeyFromWIF

func GetKeyFromWIF(wif string) (*Key, error)

GetKeyFromWIF gets PublicKey and PrivateKey from private key of WIF format.

func (*Key) SignMessage

func (key *Key) SignMessage(hash []byte) ([]byte, error)

SignMessage sign using bitcoin sign struct

type PrivateKey

type PrivateKey struct {
	// contains filtered or unexported fields
}

PrivateKey represents private key for bitcoin

func (*PrivateKey) GetWIFAddress

func (priv *PrivateKey) GetWIFAddress() string

GetWIFAddress returns WIF format string from PrivateKey

func (*PrivateKey) Sign

func (priv *PrivateKey) Sign(hash []byte) ([]byte, error)

Sign sign data.

type PublicKey

type PublicKey struct {
	// contains filtered or unexported fields
}

PublicKey represents public key for bitcoin

func GetPublicKey

func GetPublicKey(pubKeyByte []byte, isTestnet bool) (*PublicKey, error)

GetPublicKey returns PublicKey struct using public key hex string.

func (*PublicKey) GetAddress

func (pub *PublicKey) GetAddress() (string, []byte)

GetAddress returns bitcoin address from PublicKey

type RedeemScript

type RedeemScript struct {
	M          int
	PublicKeys []*PublicKey
	Script     []byte
}

RedeemScript represents Redeem script for M of N multisig transaction.

func NewRedeemScript

func NewRedeemScript(m int, publicKeys []*PublicKey) (*RedeemScript, error)

NewRedeemScript creates a M-of-N Multisig redeem script given m, n and n public keys and return RedeemScript struct.

func (*RedeemScript) CreateRawTransactionHashed

func (rs *RedeemScript) CreateRawTransactionHashed(addresses []*Amounts, service Service) ([]byte, *TX, error)

CreateRawTransactionHashed returns a hash of raw transaction for signing.

func (*RedeemScript) GetAddress

func (rs *RedeemScript) GetAddress() string

GetAddress creates P2SH multisig addresses.

func (*RedeemScript) Pay

func (rs *RedeemScript) Pay(keys []*Key, amount uint64, service Service) ([]byte, error)

Pay pays to a fund.

func (*RedeemScript) Spend

func (rs *RedeemScript) Spend(tx *TX, signs [][]byte, service Service) ([]byte, error)

Spend spend the fund.

type Service

type Service interface {
	GetServiceName() string
	GetUTXO(string, *Key) (UTXOs, error)
	SendTX([]byte) ([]byte, error)
}

Service is for getting UTXO or sending transactions , basically by using WEB API.

func NewBlockrService

func NewBlockrService() (Service, error)

NewBlockrService creates BlockrService struct for not test.

func NewBlockrServiceForTest

func NewBlockrServiceForTest() (Service, error)

NewBlockrServiceForTest creates BlockrService struct for test.

func SelectService

func SelectService(isTestnet bool) (Service, error)

SelectService returns a service randomly.

type TX

type TX struct {
	Txin     []*TXin
	Txout    []*TXout
	Locktime uint32
}

TX represents transaction.

func (*TX) MakeTX

func (tx *TX) MakeTX() ([]byte, error)

MakeTX makes transaction and return tx hex string(not send)

type TXin

type TXin struct {
	Hash  []byte
	Index uint32

	Sequence         uint32
	PrevScriptPubkey []byte
	CreateScriptSig  func(rawTransactionHashed []byte) ([]byte, error)
	// contains filtered or unexported fields
}

TXin represents tx input of a transaction.

type TXout

type TXout struct {
	Value        uint64
	ScriptPubkey []byte
}

TXout represents tx output of a transaction.

type UTXO

type UTXO struct {
	Addr   string
	Hash   []byte
	Amount uint64
	Index  uint32
	Script []byte
	Age    uint64
	Key    *Key
}

UTXO represents unspent transaction outputs.

type UTXOs

type UTXOs []*UTXO

UTXOs is for sorting UTXO

func (UTXOs) Len

func (us UTXOs) Len() int

Len returns length of UTXO

func (UTXOs) Less

func (us UTXOs) Less(i, j int) bool

Less returns true is age is smaller.

func (UTXOs) Swap

func (us UTXOs) Swap(i, j int)

Swap swaps UTXO