Persistance (#53)

* added publish TX for backwards compat.

* lowered the prototick for faster block syncing

* print useragent on startup

* added createMultiRedeemScript for genesis block generation.

* building genesis block from scratch.

* implemented merkle tree.

* starting blockhain with generated genesis hash

* Fixed bug in unspent coin state.

* fixed broken tests after genesis block.

* removed log line.

* bumped version -> 0.34.0

VERSION

@@ -1 +1 @@
-0.33.1
+0.34.0

cli/server/server.go

@@ -5,11 +5,11 @@ import (
 	"os"
 	"os/signal"
 
+	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/network"
 	"github.com/CityOfZion/neo-go/pkg/rpc"
-	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 	"github.com/urfave/cli"
@@ -32,17 +32,17 @@ func NewCommand() cli.Command {
 }
 
 func startServer(ctx *cli.Context) error {
-	net := network.ModePrivNet
+	net := config.ModePrivNet
 	if ctx.Bool("testnet") {
-		net = network.ModeTestNet
+		net = config.ModeTestNet
 	}
 	if ctx.Bool("mainnet") {
-		net = network.ModeMainNet
+		net = config.ModeMainNet
 	}
 
 	configPath := "./config"
 	configPath = ctx.String("config-path")
-	config, err := network.LoadConfig(configPath, net)
+	cfg, err := config.Load(configPath, net)
 	if err != nil {
 		return cli.NewExitError(err, 1)
 	}
@@ -50,10 +50,10 @@ func startServer(ctx *cli.Context) error {
 	interruptChan := make(chan os.Signal, 1)
 	signal.Notify(interruptChan, os.Interrupt)
 
-	serverConfig := network.NewServerConfig(config)
+	serverConfig := network.NewServerConfig(cfg)
-	chain, err := newBlockchain(net, config.ApplicationConfiguration.DataDirectoryPath)
+	chain, err := newBlockchain(cfg)
 	if err != nil {
-		err = fmt.Errorf("could not initialize blockhain: %s", err)
+		err = fmt.Errorf("could not initialize blockchain: %s", err)
 		return cli.NewExitError(err, 1)
 	}
 
@@ -61,15 +61,18 @@ func startServer(ctx *cli.Context) error {
 		log.SetLevel(log.DebugLevel)
 	}
 
-	fmt.Println(logo())
 	server := network.NewServer(serverConfig, chain)
-	rpcServer := rpc.NewServer(chain, config.ApplicationConfiguration.RPCPort, server)
+	rpcServer := rpc.NewServer(chain, cfg.ApplicationConfiguration.RPCPort, server)
 	errChan := make(chan error)
 
 	go server.Start(errChan)
 	go rpcServer.Start(errChan)
-	var shutdownErr error
 
+	fmt.Println(logo())
+	fmt.Println(server.UserAgent)
+	fmt.Println()
+
+	var shutdownErr error
 Main:
 	for {
 		select {
@@ -93,25 +96,17 @@ Main:
 	return nil
 }
 
-func newBlockchain(net network.NetMode, path string) (*core.Blockchain, error) {
+func newBlockchain(cfg config.Config) (*core.Blockchain, error) {
-	var startHash util.Uint256
-	if net == network.ModePrivNet {
-		startHash = core.GenesisHashPrivNet()
-	}
-	if net == network.ModeTestNet {
-		startHash = core.GenesisHashTestNet()
-	}
-	if net == network.ModeMainNet {
-		startHash = core.GenesisHashMainNet()
-	}
-
 	// Hardcoded for now.
-	store, err := storage.NewLevelDBStore(path, nil)
+	store, err := storage.NewLevelDBStore(
+		cfg.ApplicationConfiguration.DataDirectoryPath,
+		nil,
+	)
 	if err != nil {
 		return nil, err
 	}
 
-	return core.NewBlockchain(store, startHash)
+	return core.NewBlockchain(store, cfg.ProtocolConfiguration)
 }
 
 func logo() string {

config/config.go

@@ -1,4 +1,4 @@
-package network
+package config
 
 import (
 	"fmt"
@@ -12,6 +12,11 @@ import (
 
 const (
 	userAgentFormat = "/NEO-GO:%s/"
+
+	// Valid NetMode constants.
+	ModeMainNet NetMode = 0x00746e41 // 7630401
+	ModeTestNet NetMode = 0x74746e41 // 1953787457
+	ModePrivNet NetMode = 56753      // docker privnet
 )
 
 var (
@@ -59,16 +64,33 @@ type (
 		ProtoTickInterval time.Duration `yaml:"ProtoTickInterval"`
 		MaxPeers          int           `yaml:"MaxPeers"`
 	}
+
+	// NetMode describes the mode the blockchain will operate on.
+	NetMode uint32
 )
 
+// String implements the stringer interface.
+func (n NetMode) String() string {
+	switch n {
+	case ModePrivNet:
+		return "privnet"
+	case ModeTestNet:
+		return "testnet"
+	case ModeMainNet:
+		return "mainnet"
+	default:
+		return "net unknown"
+	}
+}
+
 // GenerateUserAgent creates user agent string based on build time environment.
 func (c Config) GenerateUserAgent() string {
 	return fmt.Sprintf(userAgentFormat, Version)
 }
 
-// LoadConfig attempts to load the config from the give
+// Loadattempts to load the config from the give
 // path and netMode.
-func LoadConfig(path string, netMode NetMode) (Config, error) {
+func Load(path string, netMode NetMode) (Config, error) {
 	configPath := fmt.Sprintf("%s/protocol.%s.yml", path, netMode)
 	if _, err := os.Stat(configPath); os.IsNotExist(err) {
 		return Config{}, errors.Wrap(err, "Unable to load config")

config/protocol.mainnet.yml

@@ -27,6 +27,6 @@ ApplicationConfiguration:
   NodePort: 20333
   Relay: true
   DialTimeout: 3
-  ProtoTickInterval: 10
+  ProtoTickInterval: 2
   MaxPeers: 50
 

config/protocol.privnet.yml

@@ -23,5 +23,5 @@ ApplicationConfiguration:
   NodePort: 20333
   Relay: true
   DialTimeout: 3
-  ProtoTickInterval: 10
+  ProtoTickInterval: 2
   MaxPeers: 50

config/protocol.testnet.yml

@@ -27,5 +27,5 @@ ApplicationConfiguration:
   NodePort: 20333
   Relay: true
   DialTimeout: 3
-  ProtoTickInterval: 10
+  ProtoTickInterval: 2
   MaxPeers: 50

pkg/core/account_state.go

@@ -3,6 +3,7 @@ package core
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 	"io"
 
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
@@ -18,11 +19,11 @@ func (a Accounts) getAndChange(s storage.Store, hash util.Uint160) (*AccountStat
 		return account, nil
 	}
 
-	var account *AccountState
+	account := &AccountState{}
 	key := storage.AppendPrefix(storage.STAccount, hash.Bytes())
 	if b, err := s.Get(key); err == nil {
 		if err := account.DecodeBinary(bytes.NewReader(b)); err != nil {
-			return nil, err
+			return nil, fmt.Errorf("failed to decode (AccountState): %s", err)
 		}
 	} else {
 		account = NewAccountState(hash)
@@ -48,6 +49,7 @@ func (a Accounts) commit(b storage.Batch) error {
 
 // AccountState represents the state of a NEO account.
 type AccountState struct {
+	Version    uint8
 	ScriptHash util.Uint160
 	IsFrozen   bool
 	Votes      []*crypto.PublicKey
@@ -57,6 +59,7 @@ type AccountState struct {
 // NewAccountState returns a new AccountState object.
 func NewAccountState(scriptHash util.Uint160) *AccountState {
 	return &AccountState{
+		Version:    0,
 		ScriptHash: scriptHash,
 		IsFrozen:   false,
 		Votes:      []*crypto.PublicKey{},
@@ -66,6 +69,9 @@ func NewAccountState(scriptHash util.Uint160) *AccountState {
 
 // DecodeBinary decodes AccountState from the given io.Reader.
 func (s *AccountState) DecodeBinary(r io.Reader) error {
+	if err := binary.Read(r, binary.LittleEndian, &s.Version); err != nil {
+		return err
+	}
 	if err := binary.Read(r, binary.LittleEndian, &s.ScriptHash); err != nil {
 		return err
 	}
@@ -101,6 +107,9 @@ func (s *AccountState) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary encode AccountState to the given io.Writer.
 func (s *AccountState) EncodeBinary(w io.Writer) error {
+	if err := binary.Write(w, binary.LittleEndian, s.Version); err != nil {
+		return err
+	}
 	if err := binary.Write(w, binary.LittleEndian, s.ScriptHash); err != nil {
 		return err
 	}
@@ -111,27 +120,35 @@ func (s *AccountState) EncodeBinary(w io.Writer) error {
 	if err := util.WriteVarUint(w, uint64(len(s.Votes))); err != nil {
 		return err
 	}
-
 	for _, point := range s.Votes {
 		if err := point.EncodeBinary(w); err != nil {
 			return err
 		}
 	}
 
-	if err := util.WriteVarUint(w, uint64(len(s.Balances))); err != nil {
+	balances := s.nonZeroBalances()
+	if err := util.WriteVarUint(w, uint64(len(balances))); err != nil {
 		return err
 	}
-
+	for k, v := range balances {
-	for k, v := range s.Balances {
+		if err := binary.Write(w, binary.LittleEndian, k); err != nil {
-		if v > 0 {
+			return err
-			if err := binary.Write(w, binary.LittleEndian, k); err != nil {
+		}
-				return err
+		if err := binary.Write(w, binary.LittleEndian, v); err != nil {
-			}
+			return err
-			if err := binary.Write(w, binary.LittleEndian, v); err != nil {
-				return err
-			}
 		}
 	}
 
 	return nil
 }
+
+// Returns only the non-zero balances for the account.
+func (s *AccountState) nonZeroBalances() map[util.Uint256]util.Fixed8 {
+	b := make(map[util.Uint256]util.Fixed8)
+	for k, v := range s.Balances {
+		if v > 0 {
+			b[k] = v
+		}
+	}
+	return b
+}

pkg/core/account_state_test.go

@@ -21,6 +21,7 @@ func TestDecodeEncodeAccountState(t *testing.T) {
 	}
 
 	a := &AccountState{
+		Version:    0,
 		ScriptHash: util.RandomUint160(),
 		IsFrozen:   true,
 		Votes:      votes,
@@ -37,6 +38,7 @@ func TestDecodeEncodeAccountState(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	assert.Equal(t, a.Version, aDecode.Version)
 	assert.Equal(t, a.ScriptHash, aDecode.ScriptHash)
 	assert.Equal(t, a.IsFrozen, aDecode.IsFrozen)
 

pkg/core/block.go

@@ -6,6 +6,7 @@ import (
 	"io"
 
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/CityOfZion/neo-go/pkg/crypto"
 	"github.com/CityOfZion/neo-go/pkg/util"
 	log "github.com/sirupsen/logrus"
 )
@@ -29,6 +30,22 @@ func (b *Block) Header() *Header {
 	}
 }
 
+// rebuildMerkleRoot rebuild the merkleroot of the block.
+func (b *Block) rebuildMerkleRoot() error {
+	hashes := make([]util.Uint256, len(b.Transactions))
+	for i, tx := range b.Transactions {
+		hashes[i] = tx.Hash()
+	}
+
+	merkle, err := crypto.NewMerkleTree(hashes)
+	if err != nil {
+		return err
+	}
+
+	b.MerkleRoot = merkle.Root()
+	return nil
+}
+
 // Verify the integrity of the block.
 func (b *Block) Verify(full bool) bool {
 	// The first TX has to be a miner transaction.

pkg/core/block_base.go

@@ -54,6 +54,9 @@ func (b *BlockBase) Verify() bool {
 
 // Hash return the hash of the block.
 func (b *BlockBase) Hash() util.Uint256 {
+	if b.hash.Equals(util.Uint256{}) {
+		b.createHash()
+	}
 	return b.hash
 }
 
@@ -92,16 +95,19 @@ func (b *BlockBase) EncodeBinary(w io.Writer) error {
 // version, PrevBlock, MerkleRoot, timestamp, and height, the nonce, NextMiner.
 // Since MerkleRoot already contains the hash value of all transactions,
 // the modification of transaction will influence the hash value of the block.
-func (b *BlockBase) createHash() (hash util.Uint256, err error) {
+func (b *BlockBase) createHash() error {
 	buf := new(bytes.Buffer)
-	if err = b.encodeHashableFields(buf); err != nil {
+	if err := b.encodeHashableFields(buf); err != nil {
-		return hash, err
+		return err
 	}
 
 	// Double hash the encoded fields.
+	var hash util.Uint256
 	hash = sha256.Sum256(buf.Bytes())
 	hash = sha256.Sum256(hash.Bytes())
-	return hash, nil
+	b.hash = hash
+
+	return nil
 }
 
 // encodeHashableFields will only encode the fields used for hashing.
@@ -155,10 +161,5 @@ func (b *BlockBase) decodeHashableFields(r io.Reader) error {
 
 	// Make the hash of the block here so we dont need to do this
 	// again.
-	hash, err := b.createHash()
+	return b.createHash()
-	if err != nil {
-		return err
-	}
-	b.hash = hash
-	return nil
 }

pkg/core/blockchain.go

@@ -4,10 +4,10 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
-	"strings"
 	"sync/atomic"
 	"time"
 
+	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
@@ -18,15 +18,19 @@ import (
 const (
 	secondsPerBlock  = 15
 	headerBatchCount = 2000
+	version          = "0.0.1"
 )
 
 var (
-	genAmount       = []int{8, 7, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
+	genAmount         = []int{8, 7, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
-	persistInterval = 5 * time.Second
+	decrementInterval = 2000000
+	persistInterval   = 5 * time.Second
 )
 
-// Blockchain holds the chain.
+// Blockchain represents the blockchain.
 type Blockchain struct {
+	config config.ProtocolConfiguration
+
 	// Any object that satisfies the BlockchainStorer interface.
 	storage.Store
 
@@ -40,8 +44,6 @@ type Blockchain struct {
 
 	blockCache *Cache
 
-	startHash util.Uint256
-
 	// All operation on headerList must be called from an
 	// headersOp to be routine safe.
 	headerList *HeaderHashList
@@ -58,12 +60,12 @@ type headersOpFunc func(headerList *HeaderHashList)
 
 // NewBlockchain return a new blockchain object the will use the
 // given Store as its underlying storage.
-func NewBlockchain(s storage.Store, startHash util.Uint256) (*Blockchain, error) {
+func NewBlockchain(s storage.Store, cfg config.ProtocolConfiguration) (*Blockchain, error) {
 	bc := &Blockchain{
+		config:        cfg,
 		Store:         s,
 		headersOp:     make(chan headersOpFunc),
 		headersOpDone: make(chan struct{}),
-		startHash:     startHash,
 		blockCache:    NewCache(),
 		verifyBlocks:  false,
 	}
@@ -77,19 +79,30 @@ func NewBlockchain(s storage.Store, startHash util.Uint256) (*Blockchain, error)
 }
 
 func (bc *Blockchain) init() error {
-	// TODO: This should be the persistance of the genisis block.
+	genesisBlock, err := createGenesisBlock(bc.config)
-	// for now we just add the genisis block start hash.
+	if err != nil {
-	bc.headerList = NewHeaderHashList(bc.startHash)
+		return err
-	bc.storedHeaderCount = 1 // genisis hash
+	}
+	bc.headerList = NewHeaderHashList(genesisBlock.Hash())
+
+	// Look in the storage for a version. If we could not the version key
+	// there is nothing stored.
+	if version, err := bc.Get(storage.SYSVersion.Bytes()); err != nil {
+		bc.Put(storage.SYSVersion.Bytes(), []byte(version))
+		if err := bc.persistBlock(genesisBlock); err != nil {
+			return err
+		}
+
+		return nil
+	}
+
+	// At this point there was no version found in the storage which
+	// implies a creating fresh storage with the version specified
+	// and the genesis block as first block.
+	log.Infof("restoring blockchain with storage version: %s", version)
 
-	// If we get an "not found" error, the store could not find
-	// the current block, which indicates there is nothing stored
-	// in the chain file.
 	currBlockBytes, err := bc.Get(storage.SYSCurrentBlock.Bytes())
 	if err != nil {
-		if strings.Contains(err.Error(), "not found") {
-			return nil
-		}
 		return err
 	}
 
@@ -98,8 +111,9 @@ func (bc *Blockchain) init() error {
 	if err != nil {
 		return err
 	}
+
 	for _, hash := range hashes {
-		if !bc.startHash.Equals(hash) {
+		if !genesisBlock.Hash().Equals(hash) {
 			bc.headerList.Add(hash)
 			bc.storedHeaderCount++
 		}
@@ -292,7 +306,7 @@ func (bc *Blockchain) persistBlock(block *Block) error {
 			}
 
 			if output.AssetID.Equals(bc.governingToken()) && len(account.Votes) > 0 {
-				log.Warnf("governing token detected in TX output need to update validators!")
+				// TODO
 			}
 		}
 
@@ -300,7 +314,7 @@ func (bc *Blockchain) persistBlock(block *Block) error {
 		for prevHash, inputs := range tx.GroupInputsByPrevHash() {
 			prevTX, _, err := bc.GetTransaction(prevHash)
 			if err != nil {
-				return err
+				return fmt.Errorf("could not find previous TX: %s", prevHash)
 			}
 			for _, input := range inputs {
 				unspent, err := unspentCoins.getAndChange(bc.Store, input.PrevHash)
@@ -316,7 +330,7 @@ func (bc *Blockchain) persistBlock(block *Block) error {
 				}
 
 				if prevTXOutput.AssetID.Equals(bc.governingToken()) {
-					log.Warnf("governing token detected in TX input need to update validators!")
+					// TODO
 				}
 
 				account.Balances[prevTXOutput.AssetID] -= prevTXOutput.Amount
@@ -347,7 +361,7 @@ func (bc *Blockchain) persistBlock(block *Block) error {
 		return err
 	}
 
-	atomic.AddUint32(&bc.blockHeight, 1)
+	atomic.StoreUint32(&bc.blockHeight, block.Index)
 	return nil
 }
 
@@ -366,6 +380,7 @@ func (bc *Blockchain) persist() (err error) {
 			hash := headerList.Get(int(bc.BlockHeight() + 1))
 			if block, ok := bc.blockCache.GetBlock(hash); ok {
 				if err = bc.persistBlock(block); err != nil {
+					log.Warnf("failed to persist blocks: %s", err)
 					return
 				}
 				bc.blockCache.Delete(hash)

pkg/core/blockchain_test.go

@@ -3,8 +3,8 @@ package core
 import (
 	"testing"
 
+	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
-	"github.com/CityOfZion/neo-go/pkg/util"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -20,7 +20,6 @@ func TestAddHeaders(t *testing.T) {
 
 	assert.Equal(t, 0, bc.blockCache.Len())
 	assert.Equal(t, h3.Index, bc.HeaderHeight())
-	assert.Equal(t, uint32(1), bc.storedHeaderCount)
 	assert.Equal(t, uint32(0), bc.BlockHeight())
 	assert.Equal(t, h3.Hash(), bc.CurrentHeaderHash())
 
@@ -30,7 +29,6 @@ func TestAddHeaders(t *testing.T) {
 	}
 
 	assert.Equal(t, h3.Index, bc.HeaderHeight())
-	assert.Equal(t, uint32(1), bc.storedHeaderCount)
 	assert.Equal(t, uint32(0), bc.BlockHeight())
 	assert.Equal(t, h3.Hash(), bc.CurrentHeaderHash())
 }
@@ -53,12 +51,20 @@ func TestAddBlock(t *testing.T) {
 	assert.Equal(t, 3, bc.blockCache.Len())
 	assert.Equal(t, lastBlock.Index, bc.HeaderHeight())
 	assert.Equal(t, lastBlock.Hash(), bc.CurrentHeaderHash())
-	assert.Equal(t, uint32(1), bc.storedHeaderCount)
+
+	t.Log(bc.blockCache)
 
 	if err := bc.persist(); err != nil {
 		t.Fatal(err)
 	}
 
+	for _, block := range blocks {
+		key := storage.AppendPrefix(storage.DataBlock, block.Hash().BytesReverse())
+		if _, err := bc.Get(key); err != nil {
+			t.Fatalf("block %s not persisted", block.Hash())
+		}
+	}
+
 	assert.Equal(t, lastBlock.Index, bc.BlockHeight())
 	assert.Equal(t, lastBlock.Hash(), bc.CurrentHeaderHash())
 	assert.Equal(t, 0, bc.blockCache.Len())
@@ -138,8 +144,11 @@ func TestGetTransaction(t *testing.T) {
 }
 
 func newTestChain(t *testing.T) *Blockchain {
-	startHash, _ := util.Uint256DecodeString("a")
+	cfg, err := config.Load("../../config", config.ModePrivNet)
-	chain, err := NewBlockchain(storage.NewMemoryStore(), startHash)
+	if err != nil {
+		t.Fatal(err)
+	}
+	chain, err := NewBlockchain(storage.NewMemoryStore(), cfg.ProtocolConfiguration)
 	if err != nil {
 		t.Fatal(err)
 	}

pkg/core/helper_test.go

@@ -31,11 +31,9 @@ func newBlock(index uint32, txs ...*transaction.Transaction) *Block {
 		},
 		Transactions: txs,
 	}
-	hash, err := b.createHash()
+
-	if err != nil {
+	b.createHash()
-		panic(err)
+
-	}
-	b.hash = hash
 	return b
 }
 

pkg/core/transaction/miner.go

@@ -7,7 +7,7 @@ import (
 
 // MinerTX represents a miner transaction.
 type MinerTX struct {
-	// Random number/identifier
+	// Random number to avoid hash collision.
 	Nonce uint32
 }
 

pkg/core/transaction/publish.go

@@ -1,19 +1,22 @@
 package transaction
 
 import (
+	"encoding/binary"
 	"io"
 
 	"github.com/CityOfZion/neo-go/pkg/smartcontract"
+	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
 // PublishTX represents a publish transaction.
-// This is deprecated and should no longer be used.
+// NOTE: This is deprecated and should no longer be used.
 type PublishTX struct {
 	Script      []byte
 	ParamList   []smartcontract.ParamType
 	ReturnType  smartcontract.ParamType
 	NeedStorage bool
 	Name        string
+	CodeVersion string
 	Author      string
 	Email       string
 	Description string
@@ -21,6 +24,54 @@ type PublishTX struct {
 
 // DecodeBinary implements the Payload interface.
 func (tx *PublishTX) DecodeBinary(r io.Reader) error {
+	var err error
+
+	tx.Script, err = util.ReadVarBytes(r)
+	if err != nil {
+		return err
+	}
+
+	lenParams := util.ReadVarUint(r)
+	tx.ParamList = make([]smartcontract.ParamType, lenParams)
+	for i := 0; i < int(lenParams); i++ {
+		var ptype uint8
+		if err := binary.Read(r, binary.LittleEndian, &ptype); err != nil {
+			return err
+		}
+		tx.ParamList[i] = smartcontract.ParamType(ptype)
+	}
+
+	var rtype uint8
+	if err := binary.Read(r, binary.LittleEndian, &rtype); err != nil {
+		return err
+	}
+	tx.ReturnType = smartcontract.ParamType(rtype)
+
+	if err := binary.Read(r, binary.LittleEndian, &tx.NeedStorage); err != nil {
+		return err
+	}
+
+	tx.Name, err = util.ReadVarString(r)
+	if err != nil {
+		return err
+	}
+	tx.CodeVersion, err = util.ReadVarString(r)
+	if err != nil {
+		return err
+	}
+	tx.Author, err = util.ReadVarString(r)
+	if err != nil {
+		return err
+	}
+	tx.Email, err = util.ReadVarString(r)
+	if err != nil {
+		return err
+	}
+	tx.Description, err = util.ReadVarString(r)
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 

pkg/core/transaction/register.go

@@ -8,34 +8,14 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
-// # 发行总量，共有2种模式：
-// # 1. 限量模式：当Amount为正数时，表示当前资产的最大总量为Amount，且不可修改（股权在未来可能会支持扩股或增发，会考虑需要公司签名或一定比例的股东签名认可）。
-// # 2. 不限量模式：当Amount等于-1时，表示当前资产可以由创建者无限量发行。这种模式的自由度最大，但是公信力最低，不建议使用。
-// # 在使用过程中，根据资产类型的不同，能够使用的总量模式也不同，具体规则如下：
-// # 1. 对于股权，只能使用限量模式；
-// # 2. 对于货币，只能使用不限量模式；
-// # 3. 对于点券，可以使用任意模式；
-//
-// In English:
-// # Total number of releases, there are 2 modes:
-// # 1. Limited amount: When Amount is positive, it means that the maximum amount of current assets is Amount
-// and can not be modified (the equity may support the expansion or issuance in the future, will consider the
-// need for company signature or a certain percentage of shareholder signature recognition ).
-// # 2. Unlimited mode: When Amount is equal to -1, it means that the current asset can be issued by the
-// creator unlimited. This mode of freedom is the largest, but the credibility of the lowest, not recommended.
-// # In the use of the process, according to the different types of assets, can use the total amount of
-// different models, the specific rules are as follows:
-// # 1. For equity, use only limited models;
-// # 2. For currencies, use only unlimited models;
-// # 3. For point coupons, you can use any pattern;
-
 // RegisterTX represents a register transaction.
+// NOTE: This is deprecated.
 type RegisterTX struct {
 	// The type of the asset being registered.
 	AssetType AssetType
 
 	// Name of the asset being registered.
-	Name []byte
+	Name string
 
 	// Amount registered
 	// Unlimited mode -0.00000001
@@ -55,14 +35,17 @@ func (tx *RegisterTX) DecodeBinary(r io.Reader) error {
 	if err := binary.Read(r, binary.LittleEndian, &tx.AssetType); err != nil {
 		return err
 	}
-	lenName := util.ReadVarUint(r)
+
-	tx.Name = make([]byte, lenName)
+	var err error
-	if err := binary.Read(r, binary.LittleEndian, &tx.Name); err != nil {
+	tx.Name, err = util.ReadVarString(r)
+	if err != nil {
 		return err
 	}
+
 	if err := binary.Read(r, binary.LittleEndian, &tx.Amount); err != nil {
 		return err
 	}
+
 	if err := binary.Read(r, binary.LittleEndian, &tx.Precision); err != nil {
 		return err
 	}
@@ -77,5 +60,20 @@ func (tx *RegisterTX) DecodeBinary(r io.Reader) error {
 
 // EncodeBinary implements the Payload interface.
 func (tx *RegisterTX) EncodeBinary(w io.Writer) error {
-	return nil
+	if err := binary.Write(w, binary.LittleEndian, tx.AssetType); err != nil {
+		return err
+	}
+	if err := util.WriteVarString(w, tx.Name); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, tx.Amount); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, tx.Precision); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, tx.Owner.Bytes()); err != nil {
+		return err
+	}
+	return binary.Write(w, binary.LittleEndian, tx.Admin)
 }

pkg/core/transaction/register_test.go

@@ -0,0 +1,63 @@
+package transaction
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRegisterTX(t *testing.T) {
+	tx := &Transaction{
+		Type:    RegisterType,
+		Version: 0,
+		Data: &RegisterTX{
+			AssetType: UtilityToken,
+			Name:      "this is some token I created",
+			Amount:    util.NewFixed8(1000000),
+			Precision: 8,
+			Owner:     &crypto.PublicKey{},
+			Admin:     util.RandomUint160(),
+		},
+	}
+
+	buf := new(bytes.Buffer)
+	assert.Nil(t, tx.EncodeBinary(buf))
+
+	txDecode := &Transaction{}
+	assert.Nil(t, txDecode.DecodeBinary(buf))
+	txData := tx.Data.(*RegisterTX)
+	txDecodeData := txDecode.Data.(*RegisterTX)
+	assert.Equal(t, txData, txDecodeData)
+	assert.Equal(t, tx.Hash(), txDecode.Hash())
+}
+
+func TestDecodeRegisterTXFromRawString(t *testing.T) {
+	rawTX := "400000455b7b226c616e67223a227a682d434e222c226e616d65223a22e5b08fe89a81e882a1227d2c7b226c616e67223a22656e222c226e616d65223a22416e745368617265227d5d0000c16ff28623000000da1745e9b549bd0bfa1a569971c77eba30cd5a4b00000000"
+	b, err := hex.DecodeString(rawTX)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tx := &Transaction{}
+	assert.Nil(t, tx.DecodeBinary(bytes.NewReader(b)))
+	assert.Equal(t, RegisterType, tx.Type)
+	txData := tx.Data.(*RegisterTX)
+	assert.Equal(t, GoverningToken, txData.AssetType)
+	assert.Equal(t, "[{\"lang\":\"zh-CN\",\"name\":\"小蚁股\"},{\"lang\":\"en\",\"name\":\"AntShare\"}]", txData.Name)
+	assert.Equal(t, util.NewFixed8(100000000), txData.Amount)
+	assert.Equal(t, uint8(0), txData.Precision)
+	assert.Equal(t, &crypto.PublicKey{}, txData.Owner)
+	assert.Equal(t, "Abf2qMs1pzQb8kYk9RuxtUb9jtRKJVuBJt", crypto.AddressFromUint160(txData.Admin))
+	assert.Equal(t, "c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b", tx.Hash().String())
+
+	buf := new(bytes.Buffer)
+	assert.Nil(t, tx.EncodeBinary(buf))
+
+	txDecode := &Transaction{}
+	assert.Nil(t, txDecode.DecodeBinary(buf))
+	assert.Equal(t, tx, txDecode)
+}

pkg/core/transaction/transaction.go

@@ -55,6 +55,9 @@ func NewTrimmedTX(hash util.Uint256) *Transaction {
 
 // Hash return the hash of the transaction.
 func (t *Transaction) Hash() util.Uint256 {
+	if t.hash.Equals(util.Uint256{}) {
+		t.createHash()
+	}
 	return t.hash
 }
 
@@ -118,13 +121,7 @@ func (t *Transaction) DecodeBinary(r io.Reader) error {
 
 	// Create the hash of the transaction at decode, so we dont need
 	// to do it anymore.
-	hash, err := t.createHash()
+	return t.createHash()
-	if err != nil {
-		return err
-	}
-	t.hash = hash
-
-	return nil
 }
 
 func (t *Transaction) decodeData(r io.Reader) error {
@@ -150,7 +147,12 @@ func (t *Transaction) decodeData(r io.Reader) error {
 	case EnrollmentType:
 		t.Data = &EnrollmentTX{}
 		return t.Data.(*EnrollmentTX).DecodeBinary(r)
-
+	case PublishType:
+		t.Data = &PublishTX{}
+		return t.Data.(*PublishTX).DecodeBinary(r)
+	case StateType:
+		t.Data = &StateTX{}
+		return t.Data.(*StateTX).DecodeBinary(r)
 	default:
 		log.Warnf("invalid TX type %s", t.Type)
 	}
@@ -223,18 +225,19 @@ func (t *Transaction) encodeHashableFields(w io.Writer) error {
 	return nil
 }
 
-func (t *Transaction) createHash() (hash util.Uint256, err error) {
+// createHash creates the hash of the transaction.
+func (t *Transaction) createHash() error {
 	buf := new(bytes.Buffer)
-	if err = t.encodeHashableFields(buf); err != nil {
+	if err := t.encodeHashableFields(buf); err != nil {
-		return
+		return err
 	}
-	sha := sha256.New()
+
-	sha.Write(buf.Bytes())
+	var hash util.Uint256
-	b := sha.Sum(nil)
+	hash = sha256.Sum256(buf.Bytes())
-	sha.Reset()
+	hash = sha256.Sum256(hash.Bytes())
-	sha.Write(b)
+	t.hash = hash
-	b = sha.Sum(nil)
+
-	return util.Uint256DecodeBytes(util.ArrayReverse(b))
+	return nil
 }
 
 // GroupTXInputsByPrevHash groups all TX inputs by their previous hash.

pkg/core/unspent_coin_state.go

@@ -3,6 +3,7 @@ package core
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 	"io"
 
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
@@ -18,11 +19,11 @@ func (u UnspentCoins) getAndChange(s storage.Store, hash util.Uint256) (*Unspent
 		return unspent, nil
 	}
 
-	var unspent *UnspentCoinState
+	unspent := &UnspentCoinState{}
 	key := storage.AppendPrefix(storage.STCoin, hash.BytesReverse())
 	if b, err := s.Get(key); err == nil {
 		if err := unspent.DecodeBinary(bytes.NewReader(b)); err != nil {
-			return nil, err
+			return nil, fmt.Errorf("failed to decode (UnspentCoinState): %s", err)
 		}
 	} else {
 		unspent = &UnspentCoinState{

pkg/core/util.go

@@ -4,29 +4,176 @@ import (
 	"bytes"
 	"encoding/binary"
 	"sort"
+	"time"
 
+	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/smartcontract"
 	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/CityOfZion/neo-go/pkg/vm"
 )
 
-// Utilities for quick bootstrapping blockchains. Normally we should
+// Creates a genesis block based on the given configuration.
-// create the genisis block. For now (to speed up development) we will add
+func createGenesisBlock(cfg config.ProtocolConfiguration) (*Block, error) {
-// The hashes manually.
+	validators, err := getValidators(cfg)
+	if err != nil {
+		return nil, err
+	}
 
-func GenesisHashPrivNet() util.Uint256 {
+	nextConsensus, err := getNextConsensusAddress(validators)
-	hash, _ := util.Uint256DecodeString("996e37358dc369912041f966f8c5d8d3a8255ba5dcbd3447f8a82b55db869099")
+	if err != nil {
-	return hash
+		return nil, err
+	}
+
+	base := BlockBase{
+		Version:       0,
+		PrevHash:      util.Uint256{},
+		Timestamp:     uint32(time.Date(2016, 7, 15, 15, 8, 21, 0, time.UTC).Unix()),
+		Index:         0,
+		ConsensusData: 2083236893,
+		NextConsensus: nextConsensus,
+		Script: &transaction.Witness{
+			InvocationScript:   []byte{},
+			VerificationScript: []byte{byte(vm.Opusht)},
+		},
+	}
+
+	governingTX := governingTokenTX()
+	utilityTX := utilityTokenTX()
+	rawScript, err := smartcontract.CreateMultiSigRedeemScript(
+		len(cfg.StandbyValidators)/2+1,
+		validators,
+	)
+	if err != nil {
+		return nil, err
+	}
+	scriptOut, err := util.Uint160FromScript(rawScript)
+	if err != nil {
+		return nil, err
+	}
+
+	block := &Block{
+		BlockBase: base,
+		Transactions: []*transaction.Transaction{
+			{
+				Type: transaction.MinerType,
+				Data: &transaction.MinerTX{
+					Nonce: 2083236893,
+				},
+				Attributes: []*transaction.Attribute{},
+				Inputs:     []*transaction.Input{},
+				Outputs:    []*transaction.Output{},
+				Scripts:    []*transaction.Witness{},
+			},
+			governingTX,
+			utilityTX,
+			{
+				Type:   transaction.IssueType,
+				Data:   &transaction.IssueTX{}, // no fields.
+				Inputs: []*transaction.Input{},
+				Outputs: []*transaction.Output{
+					{
+						AssetID:    governingTX.Hash(),
+						Amount:     governingTX.Data.(*transaction.RegisterTX).Amount,
+						ScriptHash: scriptOut,
+					},
+				},
+				Scripts: []*transaction.Witness{
+					{
+						InvocationScript:   []byte{},
+						VerificationScript: []byte{byte(vm.Opusht)},
+					},
+				},
+			},
+		},
+	}
+
+	block.rebuildMerkleRoot()
+
+	return block, nil
 }
 
-func GenesisHashTestNet() util.Uint256 {
+func governingTokenTX() *transaction.Transaction {
-	hash, _ := util.Uint256DecodeString("b3181718ef6167105b70920e4a8fbbd0a0a56aacf460d70e10ba6fa1668f1fef")
+	admin, _ := util.Uint160FromScript([]byte{byte(vm.Opusht)})
-	return hash
+	adminB, _ := crypto.Uint160DecodeAddress("Abf2qMs1pzQb8kYk9RuxtUb9jtRKJVuBJt")
+	if !admin.Equals(adminB) {
+		panic("kdjdkljfkdjfkdjf")
+	}
+	registerTX := &transaction.RegisterTX{
+		AssetType: transaction.GoverningToken,
+		Name:      "[{\"lang\":\"zh-CN\",\"name\":\"小蚁股\"},{\"lang\":\"en\",\"name\":\"AntShare\"}]",
+		Amount:    util.NewFixed8(100000000),
+		Precision: 0,
+		Owner:     &crypto.PublicKey{},
+		Admin:     admin,
+	}
+
+	tx := &transaction.Transaction{
+		Type:       transaction.RegisterType,
+		Data:       registerTX,
+		Attributes: []*transaction.Attribute{},
+		Inputs:     []*transaction.Input{},
+		Outputs:    []*transaction.Output{},
+		Scripts:    []*transaction.Witness{},
+	}
+
+	return tx
 }
 
-func GenesisHashMainNet() util.Uint256 {
+func utilityTokenTX() *transaction.Transaction {
-	hash, _ := util.Uint256DecodeString("d42561e3d30e15be6400b6df2f328e02d2bf6354c41dce433bc57687c82144bf")
+	admin, _ := util.Uint160FromScript([]byte{byte(vm.Opushf)})
-	return hash
+	registerTX := &transaction.RegisterTX{
+		AssetType: transaction.UtilityToken,
+		Name:      "[{\"lang\":\"zh-CN\",\"name\":\"小蚁币\"},{\"lang\":\"en\",\"name\":\"AntCoin\"}]",
+		Amount:    calculateUtilityAmount(),
+		Precision: 8,
+		Owner:     &crypto.PublicKey{},
+		Admin:     admin,
+	}
+	tx := &transaction.Transaction{
+		Type:       transaction.RegisterType,
+		Data:       registerTX,
+		Attributes: []*transaction.Attribute{},
+		Inputs:     []*transaction.Input{},
+		Outputs:    []*transaction.Output{},
+		Scripts:    []*transaction.Witness{},
+	}
+
+	return tx
+}
+
+func getValidators(cfg config.ProtocolConfiguration) ([]*crypto.PublicKey, error) {
+	validators := make([]*crypto.PublicKey, len(cfg.StandbyValidators))
+	for i, pubKeyStr := range cfg.StandbyValidators {
+		pubKey, err := crypto.NewPublicKeyFromString(pubKeyStr)
+		if err != nil {
+			return nil, err
+		}
+		validators[i] = pubKey
+	}
+	return validators, nil
+}
+
+func getNextConsensusAddress(validators []*crypto.PublicKey) (val util.Uint160, err error) {
+	vlen := len(validators)
+	raw, err := smartcontract.CreateMultiSigRedeemScript(
+		vlen-(vlen-1)/3,
+		validators,
+	)
+	if err != nil {
+		return val, err
+	}
+	return util.Uint160FromScript(raw)
+}
+
+func calculateUtilityAmount() util.Fixed8 {
+	sum := 0
+	for i := 0; i < len(genAmount); i++ {
+		sum += genAmount[i]
+	}
+	return util.NewFixed8(sum * decrementInterval)
 }
 
 // headerSliceReverse reverses the given slice of *Header.

pkg/core/util_test.go

@@ -0,0 +1,61 @@
+package core
+
+import (
+	"testing"
+
+	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGenesisBlockMainNet(t *testing.T) {
+	cfg, err := config.Load("../../config", config.ModeMainNet)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	block, err := createGenesisBlock(cfg.ProtocolConfiguration)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expect := "d42561e3d30e15be6400b6df2f328e02d2bf6354c41dce433bc57687c82144bf"
+	assert.Equal(t, expect, block.Hash().String())
+}
+
+func TestGetConsensusAddressMainNet(t *testing.T) {
+	var (
+		consensusAddr   = "APyEx5f4Zm4oCHwFWiSTaph1fPBxZacYVR"
+		consensusScript = "59e75d652b5d3827bf04c165bbe9ef95cca4bf55"
+	)
+
+	cfg, err := config.Load("../../config", config.ModeMainNet)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	validators, err := getValidators(cfg.ProtocolConfiguration)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	script, err := getNextConsensusAddress(validators)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, consensusScript, script.String())
+	assert.Equal(t, consensusAddr, crypto.AddressFromUint160(script))
+}
+
+func TestUtilityTokenTX(t *testing.T) {
+	expect := "602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7"
+	tx := utilityTokenTX()
+	assert.Equal(t, expect, tx.Hash().String())
+}
+
+func TestGoverningTokenTX(t *testing.T) {
+	expect := "c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b"
+	tx := governingTokenTX()
+	assert.Equal(t, expect, tx.Hash().String())
+}

pkg/crypto/elliptic_curve.go

@@ -88,8 +88,6 @@ func ECPointFromReader(r io.Reader) (point ECPoint, err error) {
 		return
 	}
 
-	fmt.Println(f)
-
 	// Infinity
 	if f == 0 {
 		return ECPoint{

pkg/crypto/merkle_tree.go

@@ -0,0 +1,99 @@
+package crypto
+
+import (
+	"crypto/sha256"
+	"errors"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// MerkleTree implementation.
+
+type MerkleTree struct {
+	root  *MerkleTreeNode
+	depth int
+}
+
+// NewMerkleTree returns new MerkleTree object.
+func NewMerkleTree(hashes []util.Uint256) (*MerkleTree, error) {
+	if len(hashes) == 0 {
+		return nil, errors.New("length of the hashes cannot be zero")
+	}
+
+	nodes := make([]*MerkleTreeNode, len(hashes))
+	for i := 0; i < len(hashes); i++ {
+		nodes[i] = &MerkleTreeNode{
+			hash: hashes[i],
+		}
+	}
+
+	root, err := buildMerkleTree(nodes)
+	if err != nil {
+		return nil, err
+	}
+
+	return &MerkleTree{
+		root:  root,
+		depth: 1,
+	}, nil
+}
+
+// Root return the computed root hash of the MerkleTree.
+func (t *MerkleTree) Root() util.Uint256 {
+	return t.root.hash
+}
+
+func buildMerkleTree(leaves []*MerkleTreeNode) (*MerkleTreeNode, error) {
+	if len(leaves) == 0 {
+		return nil, errors.New("length of the leaves cannot be zero")
+	}
+	if len(leaves) == 1 {
+		return leaves[0], nil
+	}
+
+	parents := make([]*MerkleTreeNode, (len(leaves)+1)/2)
+	for i := 0; i < len(parents); i++ {
+		parents[i] = &MerkleTreeNode{}
+		parents[i].leftChild = leaves[i*2]
+		leaves[i*2].parent = parents[i]
+
+		if i*2+1 == len(leaves) {
+			parents[i].rightChild = parents[i].leftChild
+		} else {
+			parents[i].rightChild = leaves[i*2+1]
+			leaves[i*2+1].parent = parents[i]
+		}
+
+		b1 := parents[i].leftChild.hash.Bytes()
+		b2 := parents[i].rightChild.hash.Bytes()
+		b1 = append(b1, b2...)
+		parents[i].hash = hash256(b1)
+	}
+
+	return buildMerkleTree(parents)
+}
+
+// MerkleTreeNode represents a node in the MerkleTree.
+type MerkleTreeNode struct {
+	hash       util.Uint256
+	parent     *MerkleTreeNode
+	leftChild  *MerkleTreeNode
+	rightChild *MerkleTreeNode
+}
+
+// IsLeaf returns whether this node is a leaf node or not.
+func (n *MerkleTreeNode) IsLeaf() bool {
+	return n.leftChild == nil && n.rightChild == nil
+}
+
+// IsRoot returns whether this node is a root node or not.
+func (n *MerkleTreeNode) IsRoot() bool {
+	return n.parent == nil
+}
+
+func hash256(b []byte) util.Uint256 {
+	var hash util.Uint256
+	hash = sha256.Sum256(b)
+	hash = sha256.Sum256(hash.Bytes())
+	return hash
+}

pkg/crypto/merkle_tree_test.go

@@ -0,0 +1,29 @@
+package crypto
+
+import (
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestComputeMerkleTree(t *testing.T) {
+	rawHashes := []string{
+		"fb5bd72b2d6792d75dc2f1084ffa9e9f70ca85543c717a6b13d9959b452a57d6",
+		"c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b",
+		"602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7",
+		"3631f66024ca6f5b033d7e0809eb993443374830025af904fb51b0334f127cda",
+	}
+
+	hashes := make([]util.Uint256, len(rawHashes))
+	for i, str := range rawHashes {
+		hash, _ := util.Uint256DecodeString(str)
+		hashes[i] = hash
+	}
+
+	merkle, err := NewMerkleTree(hashes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, "803ff4abe3ea6533bcc0be574efa02f83ae8fdc651c879056b0d9be336c01bf4", merkle.Root().String())
+}

pkg/crypto/public_key.go

@@ -3,18 +3,59 @@ package crypto
 import (
 	"bytes"
 	"encoding/binary"
+	"encoding/hex"
 	"fmt"
 	"io"
 	"math/big"
 )
 
-// PublicKey represents a public key.
+// PublicKeys is a list of public keys.
+type PublicKeys []*PublicKey
+
+func (keys PublicKeys) Len() int      { return len(keys) }
+func (keys PublicKeys) Swap(i, j int) { keys[i], keys[j] = keys[j], keys[i] }
+func (keys PublicKeys) Less(i, j int) bool {
+	if keys[i].X.Cmp(keys[j].X) == -1 {
+		return true
+	}
+	if keys[i].X.Cmp(keys[j].X) == 1 {
+		return false
+	}
+	if keys[i].X.Cmp(keys[j].X) == 0 {
+		return false
+	}
+
+	return keys[i].Y.Cmp(keys[j].Y) == -1
+}
+
+// PublicKey represents a public key and provides a high level
+// API around the ECPoint.
 type PublicKey struct {
 	ECPoint
 }
 
+// NewPublicKeyFromString return a public key created from the
+// given hex string.
+func NewPublicKeyFromString(s string) (*PublicKey, error) {
+	b, err := hex.DecodeString(s)
+	if err != nil {
+		return nil, err
+	}
+
+	pubKey := &PublicKey{}
+	if err := pubKey.DecodeBinary(bytes.NewReader(b)); err != nil {
+		return nil, err
+	}
+
+	return pubKey, nil
+}
+
 // Bytes returns the byte array representation of the public key.
 func (p *PublicKey) Bytes() []byte {
+	if p.IsInfinity() {
+		return []byte{0x00}
+	}
+
 	var (
 		x       = p.X.Bytes()
 		paddedX = append(bytes.Repeat([]byte{0x00}, 32-len(x)), x...)
@@ -35,6 +76,12 @@ func (p *PublicKey) DecodeBinary(r io.Reader) error {
 		return err
 	}
 
+	// Infinity
+	if prefix == 0x00 {
+		p.ECPoint = ECPoint{}
+		return nil
+	}
+
 	// Compressed public keys.
 	if prefix == 0x02 || prefix == 0x03 {
 		c := NewEllipticCurve()

pkg/crypto/public_key_test.go

@@ -2,11 +2,23 @@ package crypto
 
 import (
 	"bytes"
+	"encoding/hex"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
+func TestEncodeDecodeInfinity(t *testing.T) {
+	key := &PublicKey{ECPoint{}}
+	buf := new(bytes.Buffer)
+	assert.Nil(t, key.EncodeBinary(buf))
+	assert.Equal(t, 1, buf.Len())
+
+	keyDecode := &PublicKey{}
+	assert.Nil(t, keyDecode.DecodeBinary(buf))
+	assert.Equal(t, []byte{0x00}, keyDecode.Bytes())
+}
+
 func TestEncodeDecodePublicKey(t *testing.T) {
 	for i := 0; i < 4; i++ {
 		p := &PublicKey{RandomECPoint()}
@@ -18,3 +30,12 @@ func TestEncodeDecodePublicKey(t *testing.T) {
 		assert.Equal(t, p.X, pDecode.X)
 	}
 }
+
+func TestDecodeFromString(t *testing.T) {
+	str := "03b209fd4f53a7170ea4444e0cb0a6bb6a53c2bd016926989cf85f9b0fba17a70c"
+	pubKey, err := NewPublicKeyFromString(str)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, str, hex.EncodeToString(pubKey.Bytes()))
+}

pkg/network/message.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 
+	"github.com/CityOfZion/neo-go/config"
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/network/payload"
@@ -23,34 +24,10 @@ var (
 	errChecksumMismatch = errors.New("checksum mismatch")
 )
 
-// NetMode type that is compatible with netModes below.
-type NetMode uint32
-
-// String implements the stringer interface.
-func (n NetMode) String() string {
-	switch n {
-	case ModePrivNet:
-		return "privnet"
-	case ModeTestNet:
-		return "testnet"
-	case ModeMainNet:
-		return "mainnet"
-	default:
-		return "net unknown"
-	}
-}
-
-// Values used for the magic field, according to the docs.
-const (
-	ModeMainNet NetMode = 0x00746e41 // 7630401
-	ModeTestNet NetMode = 0x74746e41 // 1953787457
-	ModePrivNet NetMode = 56753      // docker privnet
-)
-
 // Message is the complete message send between nodes.
 type Message struct {
 	// NetMode of the node that sends this message.
-	Magic NetMode
+	Magic config.NetMode
 
 	// Command is utf8 code, of which the length is 12 bytes,
 	// the extra part is filled with 0.
@@ -88,7 +65,7 @@ const (
 )
 
 // NewMessage returns a new message with the given payload.
-func NewMessage(magic NetMode, cmd CommandType, p payload.Payload) *Message {
+func NewMessage(magic config.NetMode, cmd CommandType, p payload.Payload) *Message {
 	var (
 		size     uint32
 		checksum []byte

pkg/network/server_config.go

@@ -3,6 +3,7 @@ package network
 import (
 	"time"
 
+	"github.com/CityOfZion/neo-go/config"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -23,7 +24,7 @@ type (
 		// ModePrivNet docker private network.
 		// ModeTestNet NEO test network.
 		// ModeMainNet NEO main network.
-		Net NetMode
+		Net config.NetMode
 
 		// Relay determins whether the server is forwarding its inventory.
 		Relay bool
@@ -45,12 +46,12 @@ type (
 
 // NewServerConfig creates a new ServerConfig struct
 // using the main applications config.
-func NewServerConfig(config Config) ServerConfig {
+func NewServerConfig(cfg config.Config) ServerConfig {
-	appConfig := config.ApplicationConfiguration
+	appConfig := cfg.ApplicationConfiguration
-	protoConfig := config.ProtocolConfiguration
+	protoConfig := cfg.ProtocolConfiguration
 
 	return ServerConfig{
-		UserAgent:         config.GenerateUserAgent(),
+		UserAgent:         cfg.GenerateUserAgent(),
 		ListenTCP:         appConfig.NodePort,
 		Net:               protoConfig.Magic,
 		Relay:             appConfig.Relay,

pkg/smartcontract/contract.go

@@ -1,4 +1,34 @@
 package smartcontract
 
-// Contract represents a NEO smartcontract.
+import (
-type Contract struct{}
+	"bytes"
+	"fmt"
+	"sort"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/vm"
+)
+
+// CreateMultiSigRedeemScript will create a script runnable by the VM.
+func CreateMultiSigRedeemScript(m int, publicKeys crypto.PublicKeys) ([]byte, error) {
+	if m <= 1 {
+		return nil, fmt.Errorf("param m cannot be smaller or equal to 1 got %d", m)
+	}
+	if m > len(publicKeys) {
+		return nil, fmt.Errorf("length of the signatures (%d) is higher then the number of public keys", m)
+	}
+	if m > 1024 {
+		return nil, fmt.Errorf("public key count %d exceeds maximum of length 1024", len(publicKeys))
+	}
+
+	buf := new(bytes.Buffer)
+	vm.EmitInt(buf, int64(m))
+	sort.Sort(publicKeys)
+	for _, pubKey := range publicKeys {
+		vm.EmitBytes(buf, pubKey.Bytes())
+	}
+	vm.EmitInt(buf, int64(len(publicKeys)))
+	vm.EmitOpcode(buf, vm.Ocheckmultisig)
+
+	return buf.Bytes(), nil
+}

pkg/smartcontract/contract_test.go

@@ -0,0 +1,41 @@
+package smartcontract
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/CityOfZion/neo-go/pkg/vm"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateMultiSigRedeemScript(t *testing.T) {
+	val1, _ := crypto.NewPublicKeyFromString("03b209fd4f53a7170ea4444e0cb0a6bb6a53c2bd016926989cf85f9b0fba17a70c")
+	val2, _ := crypto.NewPublicKeyFromString("02df48f60e8f3e01c48ff40b9b7f1310d7a8b2a193188befe1c2e3df740e895093")
+	val3, _ := crypto.NewPublicKeyFromString("03b8d9d5771d8f513aa0869b9cc8d50986403b78c6da36890638c3d46a5adce04a")
+
+	validators := []*crypto.PublicKey{val1, val2, val3}
+
+	out, err := CreateMultiSigRedeemScript(3, validators)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	buf := bytes.NewBuffer(out)
+	b, _ := buf.ReadByte()
+	assert.Equal(t, vm.Opush3, vm.Opcode(b))
+
+	for i := 0; i < len(validators); i++ {
+		b, err := util.ReadVarBytes(buf)
+		if err != nil {
+			t.Fatal(err)
+		}
+		assert.Equal(t, validators[i].Bytes(), b)
+	}
+
+	b, _ = buf.ReadByte()
+	assert.Equal(t, vm.Opush3, vm.Opcode(b))
+	b, _ = buf.ReadByte()
+	assert.Equal(t, vm.Ocheckmultisig, vm.Opcode(b))
+}

pkg/util/fixed8.go

@@ -5,6 +5,8 @@ import (
 	"strconv"
 )
 
+const decimals = 100000000
+
 // Fixed8 represents a fixed-point number with precision 10^-8.
 type Fixed8 int64
 
@@ -16,9 +18,9 @@ func (f Fixed8) String() string {
 		buf.WriteRune('-')
 		val = -val
 	}
-	str := strconv.FormatInt(val/100000000, 10)
+	str := strconv.FormatInt(val/decimals, 10)
 	buf.WriteString(str)
-	val %= 100000000
+	val %= decimals
 	if val > 0 {
 		buf.WriteRune('.')
 		str = strconv.FormatInt(val, 10)
@@ -29,3 +31,13 @@ func (f Fixed8) String() string {
 	}
 	return buf.String()
 }
+
+// Value returns the original value representing the Fixed8.
+func (f Fixed8) Value() int64 {
+	return int64(f) / int64(decimals)
+}
+
+// NewFixed8 return a new Fixed8 type multiplied by decimals.
+func NewFixed8(val int) Fixed8 {
+	return Fixed8(decimals * val)
+}

pkg/util/fixed8_test.go

@@ -0,0 +1,16 @@
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewFixed8(t *testing.T) {
+	values := []int{9000, 100000000, 5, 10945}
+
+	for _, val := range values {
+		assert.Equal(t, Fixed8(val*decimals), NewFixed8(val))
+		assert.Equal(t, int64(val), NewFixed8(val).Value())
+	}
+}

pkg/util/io.go

@@ -65,6 +65,35 @@ func WriteVarUint(w io.Writer, val uint64) error {
 	return nil
 }
 
+// ReadVarBytes reads a variable length byte array.
+func ReadVarBytes(r io.Reader) ([]byte, error) {
+	n := ReadVarUint(r)
+	b := make([]byte, n)
+	if err := binary.Read(r, binary.LittleEndian, b); err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+// ReadVarString reads a variable length string.
+func ReadVarString(r io.Reader) (string, error) {
+	b, err := ReadVarBytes(r)
+	return string(b), err
+}
+
+// WriteVarString writes a variable length string.
+func WriteVarString(w io.Writer, s string) error {
+	return WriteVarBytes(w, []byte(s))
+}
+
+// WriteVarBytes writes a variable length byte array.
+func WriteVarBytes(w io.Writer, b []byte) error {
+	if err := WriteVarUint(w, uint64(len(b))); err != nil {
+		return err
+	}
+	return binary.Write(w, binary.LittleEndian, b)
+}
+
 // Read2000Uint256Hashes attempt to read 2000 Uint256 hashes from
 // the given byte array.
 func Read2000Uint256Hashes(b []byte) ([]Uint256, error) {

pkg/util/uint160.go

@@ -1,9 +1,12 @@
 package util
 
 import (
+	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+
+	"golang.org/x/crypto/ripemd160"
 )
 
 const uint160Size = 20
@@ -34,6 +37,17 @@ func Uint160DecodeBytes(b []byte) (u Uint160, err error) {
 	return
 }
 
+// Uint160FromScript returns a Uint160 type from a raw script.
+func Uint160FromScript(script []byte) (u Uint160, err error) {
+	sha := sha256.New()
+	sha.Write(script)
+	b := sha.Sum(nil)
+	ripemd := ripemd160.New()
+	ripemd.Write(b)
+	b = ripemd.Sum(nil)
+	return Uint160DecodeBytes(b)
+}
+
 // Bytes returns the byte slice representation of u.
 func (u Uint160) Bytes() []byte {
 	b := make([]byte, uint160Size)
@@ -43,6 +57,11 @@ func (u Uint160) Bytes() []byte {
 	return b
 }
 
+// BytesReverse return a reversed byte representation of u.
+func (u Uint160) BytesReverse() []byte {
+	return ArrayReverse(u.Bytes())
+}
+
 // String implements the stringer interface.
 func (u Uint160) String() string {
 	return hex.EncodeToString(u.Bytes())

pkg/util/uint160_test.go

@@ -1 +1,50 @@
 package util
+
+import (
+	"encoding/hex"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUInt160DecodeString(t *testing.T) {
+	hexStr := "2d3b96ae1bcc5a585e075e3b81920210dec16302"
+	val, err := Uint160DecodeString(hexStr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, hexStr, val.String())
+}
+
+func TestUint160DecodeBytes(t *testing.T) {
+	hexStr := "2d3b96ae1bcc5a585e075e3b81920210dec16302"
+	b, err := hex.DecodeString(hexStr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	val, err := Uint160DecodeBytes(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, hexStr, val.String())
+}
+
+func TestUInt160Equals(t *testing.T) {
+	a := "2d3b96ae1bcc5a585e075e3b81920210dec16302"
+	b := "4d3b96ae1bcc5a585e075e3b81920210dec16302"
+
+	ua, err := Uint160DecodeString(a)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ub, err := Uint160DecodeString(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if ua.Equals(ub) {
+		t.Fatalf("%s and %s cannot be equal", ua, ub)
+	}
+	if !ua.Equals(ua) {
+		t.Fatalf("%s and %s must be equal", ua, ua)
+	}
+}