diff --git a/VERSION b/VERSION
index 26bea73e8..9eb2aa3f1 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.31.0
+0.32.0
diff --git a/pkg/core/account_state.go b/pkg/core/account_state.go
new file mode 100644
index 000000000..f32bb0bd6
--- /dev/null
+++ b/pkg/core/account_state.go
@@ -0,0 +1,137 @@
+package core
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// Accounts is mapping between a account address and AccountState.
+type Accounts map[util.Uint160]*AccountState
+
+func (a Accounts) getAndChange(s storage.Store, hash util.Uint160) (*AccountState, error) {
+	if account, ok := a[hash]; ok {
+		return account, nil
+	}
+
+	var 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
+		}
+	} else {
+		account = NewAccountState(hash)
+	}
+
+	a[hash] = account
+	return account, nil
+}
+
+// commit writes all account states to the given Batch.
+func (a Accounts) commit(b storage.Batch) error {
+	buf := new(bytes.Buffer)
+	for hash, state := range a {
+		if err := state.EncodeBinary(buf); err != nil {
+			return err
+		}
+		key := storage.AppendPrefix(storage.STAccount, hash.Bytes())
+		b.Put(key, buf.Bytes())
+		buf.Reset()
+	}
+	return nil
+}
+
+// AccountState represents the state of a NEO account.
+type AccountState struct {
+	ScriptHash util.Uint160
+	IsFrozen   bool
+	Votes      []*crypto.PublicKey
+	Balances   map[util.Uint256]util.Fixed8
+}
+
+// NewAccountState returns a new AccountState object.
+func NewAccountState(scriptHash util.Uint160) *AccountState {
+	return &AccountState{
+		ScriptHash: scriptHash,
+		IsFrozen:   false,
+		Votes:      []*crypto.PublicKey{},
+		Balances:   make(map[util.Uint256]util.Fixed8),
+	}
+}
+
+// DecodeBinary decodes AccountState from the given io.Reader.
+func (s *AccountState) DecodeBinary(r io.Reader) error {
+	if err := binary.Read(r, binary.LittleEndian, &s.ScriptHash); err != nil {
+		return err
+	}
+	if err := binary.Read(r, binary.LittleEndian, &s.IsFrozen); err != nil {
+		return err
+	}
+
+	lenVotes := util.ReadVarUint(r)
+	s.Votes = make([]*crypto.PublicKey, lenVotes)
+	for i := 0; i < int(lenVotes); i++ {
+		s.Votes[i] = &crypto.PublicKey{}
+		if err := s.Votes[i].DecodeBinary(r); err != nil {
+			return err
+		}
+	}
+
+	s.Balances = make(map[util.Uint256]util.Fixed8)
+	lenBalances := util.ReadVarUint(r)
+	for i := 0; i < int(lenBalances); i++ {
+		key := util.Uint256{}
+		if err := binary.Read(r, binary.LittleEndian, &key); err != nil {
+			return err
+		}
+		var val util.Fixed8
+		if err := binary.Read(r, binary.LittleEndian, &val); err != nil {
+			return err
+		}
+		s.Balances[key] = val
+	}
+
+	return nil
+}
+
+// EncodeBinary encode AccountState to the given io.Writer.
+func (s *AccountState) EncodeBinary(w io.Writer) error {
+	if err := binary.Write(w, binary.LittleEndian, s.ScriptHash); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, s.IsFrozen); err != nil {
+		return err
+	}
+
+	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 {
+		return err
+	}
+
+	for k, v := range s.Balances {
+		if v > 0 {
+			if err := binary.Write(w, binary.LittleEndian, k); err != nil {
+				return err
+			}
+			if err := binary.Write(w, binary.LittleEndian, v); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
diff --git a/pkg/core/account_state_test.go b/pkg/core/account_state_test.go
new file mode 100644
index 000000000..043891da8
--- /dev/null
+++ b/pkg/core/account_state_test.go
@@ -0,0 +1,47 @@
+package core
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDecodeEncodeAccountState(t *testing.T) {
+	var (
+		n        = 10
+		balances = make(map[util.Uint256]util.Fixed8)
+		votes    = make([]*crypto.PublicKey, n)
+	)
+	for i := 0; i < n; i++ {
+		balances[util.RandomUint256()] = util.Fixed8(int64(util.RandomInt(1, 10000)))
+		votes[i] = &crypto.PublicKey{crypto.RandomECPoint()}
+	}
+
+	a := &AccountState{
+		ScriptHash: util.RandomUint160(),
+		IsFrozen:   true,
+		Votes:      votes,
+		Balances:   balances,
+	}
+
+	buf := new(bytes.Buffer)
+	if err := a.EncodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	aDecode := &AccountState{}
+	if err := aDecode.DecodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, a.ScriptHash, aDecode.ScriptHash)
+	assert.Equal(t, a.IsFrozen, aDecode.IsFrozen)
+
+	for i, vote := range a.Votes {
+		assert.Equal(t, vote.X, aDecode.Votes[i].X)
+	}
+	assert.Equal(t, a.Balances, aDecode.Balances)
+}
diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
index 63580868d..b64de75a8 100644
--- a/pkg/core/blockchain.go
+++ b/pkg/core/blockchain.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
 	log "github.com/sirupsen/logrus"
 )
@@ -154,6 +155,13 @@ func (bc *Blockchain) run() {
 	}
 }
 
+// For now this will return a hardcoded hash of the NEO governing token.
+func (bc *Blockchain) governingToken() util.Uint256 {
+	neoNativeAsset := "c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b"
+	val, _ := util.Uint256DecodeString(neoNativeAsset)
+	return val
+}
+
 // AddBlock processes the given block and will add it to the cache so it
 // can be persisted.
 func (bc *Blockchain) AddBlock(block *Block) error {
@@ -246,15 +254,99 @@ func (bc *Blockchain) processHeader(h *Header, batch storage.Batch, headerList *
 	return nil
 }
 
+// TODO: persistBlock needs some more love, its implemented as in the original
+// project. This for the sake of development speed and understanding of what
+// is happening here, quite allot as you can see :). If things are wired together
+// and all tests are in place, we can make a more optimized and cleaner implementation.
 func (bc *Blockchain) persistBlock(block *Block) error {
-	batch := bc.Batch()
+	var (
+		batch        = bc.Batch()
+		unspentCoins = make(UnspentCoins)
+		accounts     = make(Accounts)
+	)
 
 	storeAsBlock(batch, block, 0)
 	storeAsCurrentBlock(batch, block)
 
+	for _, tx := range block.Transactions {
+		storeAsTransaction(batch, tx, block.Index)
+
+		// Add CoinStateConfirmed for each tx output.
+		unspent := make([]CoinState, len(tx.Outputs))
+		for i := 0; i < len(tx.Outputs); i++ {
+			unspent[i] = CoinStateConfirmed
+		}
+		unspentCoins[tx.Hash()] = &UnspentCoinState{unspent}
+
+		// Process TX outputs.
+		for _, output := range tx.Outputs {
+			account, err := accounts.getAndChange(bc.Store, output.ScriptHash)
+			if err != nil {
+				return err
+			}
+
+			if _, ok := account.Balances[output.AssetID]; ok {
+				account.Balances[output.AssetID] += output.Amount
+			} else {
+				account.Balances[output.AssetID] = output.Amount
+			}
+
+			if output.AssetID.Equals(bc.governingToken()) && len(account.Votes) > 0 {
+				log.Warnf("governing token detected in TX output need to update validators!")
+			}
+		}
+
+		// Process TX inputs that are grouped by previous hash.
+		for prevHash, inputs := range tx.GroupInputsByPrevHash() {
+			prevTX, _, err := bc.GetTransaction(prevHash)
+			if err != nil {
+				return err
+			}
+			for _, input := range inputs {
+				unspent, err := unspentCoins.getAndChange(bc.Store, input.PrevHash)
+				if err != nil {
+					return err
+				}
+				unspent.states[input.PrevIndex] = CoinStateSpent
+
+				prevTXOutput := prevTX.Outputs[input.PrevIndex]
+				account, err := accounts.getAndChange(bc.Store, prevTXOutput.ScriptHash)
+				if err != nil {
+					return err
+				}
+
+				if prevTXOutput.AssetID.Equals(bc.governingToken()) {
+					log.Warnf("governing token detected in TX input need to update validators!")
+				}
+
+				account.Balances[prevTXOutput.AssetID] -= prevTXOutput.Amount
+			}
+		}
+
+		// Process the underlying type of the TX.
+		switch tx.Data.(type) {
+		case *transaction.RegisterTX:
+		case *transaction.IssueTX:
+		case *transaction.ClaimTX:
+		case *transaction.EnrollmentTX:
+		case *transaction.StateTX:
+		case *transaction.PublishTX:
+		case *transaction.InvocationTX:
+			log.Warn("invocation TX but we have no VM, o noo :(")
+		}
+	}
+
+	// Persist all to storage.
+	if err := accounts.commit(batch); err != nil {
+		return err
+	}
+	if err := unspentCoins.commit(batch); err != nil {
+		return err
+	}
 	if err := bc.PutBatch(batch); err != nil {
 		return err
 	}
+
 	atomic.AddUint32(&bc.blockHeight, 1)
 	return nil
 }
@@ -302,6 +394,27 @@ func (bc *Blockchain) headerListLen() (n int) {
 	return
 }
 
+// GetTransaction returns a TX and its height by the given hash.
+func (bc *Blockchain) GetTransaction(hash util.Uint256) (*transaction.Transaction, uint32, error) {
+	key := storage.AppendPrefix(storage.DataTransaction, hash.BytesReverse())
+	b, err := bc.Get(key)
+	if err != nil {
+		return nil, 0, err
+	}
+	r := bytes.NewReader(b)
+
+	var height uint32
+	if err := binary.Read(r, binary.LittleEndian, &height); err != nil {
+		return nil, 0, err
+	}
+
+	tx := &transaction.Transaction{}
+	if err := tx.DecodeBinary(r); err != nil {
+		return nil, 0, err
+	}
+	return tx, height, nil
+}
+
 // GetBlock returns a Block by the given hash.
 func (bc *Blockchain) GetBlock(hash util.Uint256) (*Block, error) {
 	key := storage.AppendPrefix(storage.DataBlock, hash.BytesReverse())
diff --git a/pkg/core/blockchain_test.go b/pkg/core/blockchain_test.go
index 8d4e0c5e0..109a557a7 100644
--- a/pkg/core/blockchain_test.go
+++ b/pkg/core/blockchain_test.go
@@ -122,6 +122,21 @@ func TestHasBlock(t *testing.T) {
 	assert.False(t, bc.HasBlock(newBlock.Hash()))
 }
 
+func TestGetTransaction(t *testing.T) {
+	block := getDecodedBlock(t, 1)
+	bc := newTestChain(t)
+
+	assert.Nil(t, bc.AddBlock(block))
+	assert.Nil(t, bc.persistBlock(block))
+
+	tx, height, err := bc.GetTransaction(block.Transactions[0].Hash())
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, block.Index, height)
+	assert.Equal(t, block.Transactions[0], tx)
+}
+
 func newTestChain(t *testing.T) *Blockchain {
 	startHash, _ := util.Uint256DecodeString("a")
 	chain, err := NewBlockchain(storage.NewMemoryStore(), startHash)
diff --git a/pkg/core/coin_state.go b/pkg/core/coin_state.go
new file mode 100644
index 000000000..8232977f3
--- /dev/null
+++ b/pkg/core/coin_state.go
@@ -0,0 +1,12 @@
+package core
+
+// CoinState represents the state of a coin.
+type CoinState uint8
+
+// Viable CoinState constants.
+const (
+	CoinStateConfirmed CoinState = 0
+	CoinStateSpent     CoinState = 1 << 1
+	CoinStateClaimed   CoinState = 1 << 2
+	CoinStateFrozen    CoinState = 1 << 5
+)
diff --git a/pkg/core/storage/leveldb_store.go b/pkg/core/storage/leveldb_store.go
index 71e83f11f..a847a3db3 100644
--- a/pkg/core/storage/leveldb_store.go
+++ b/pkg/core/storage/leveldb_store.go
@@ -51,7 +51,8 @@ func (s *LevelDBStore) Seek(key []byte, f func(k, v []byte)) {
 	iter.Release()
 }
 
-// Batch implements the Batch interface and returns a compatible Batch.
+// Batch implements the Batch interface and returns a leveldb
+// compatible Batch.
 func (s *LevelDBStore) Batch() Batch {
 	return new(leveldb.Batch)
 }
diff --git a/pkg/core/storage/memory_store.go b/pkg/core/storage/memory_store.go
index a63813a92..e18147490 100644
--- a/pkg/core/storage/memory_store.go
+++ b/pkg/core/storage/memory_store.go
@@ -1,5 +1,9 @@
 package storage
 
+import (
+	"encoding/hex"
+)
+
 // MemoryStore is an in-memory implementation of a Store, mainly
 // used for testing. Do not use MemoryStore in production.
 type MemoryStore struct {
@@ -31,7 +35,7 @@ func NewMemoryStore() *MemoryStore {
 
 // Get implements the Store interface.
 func (s *MemoryStore) Get(key []byte) ([]byte, error) {
-	if val, ok := s.mem[string(key)]; ok {
+	if val, ok := s.mem[makeKey(key)]; ok {
 		return val, nil
 	}
 	return nil, ErrKeyNotFound
@@ -39,7 +43,7 @@ func (s *MemoryStore) Get(key []byte) ([]byte, error) {
 
 // Put implementes the Store interface.
 func (s *MemoryStore) Put(key, value []byte) error {
-	s.mem[string(key)] = value
+	s.mem[makeKey(key)] = value
 	return nil
 }
 
@@ -62,3 +66,7 @@ func (s *MemoryStore) Batch() Batch {
 		m: make(map[*[]byte][]byte),
 	}
 }
+
+func makeKey(k []byte) string {
+	return hex.EncodeToString(k)
+}
diff --git a/pkg/core/storage/memory_store_test.go b/pkg/core/storage/memory_store_test.go
index 883f14cfb..1f2ba3ed1 100644
--- a/pkg/core/storage/memory_store_test.go
+++ b/pkg/core/storage/memory_store_test.go
@@ -22,6 +22,17 @@ func TestGetPut(t *testing.T) {
 	assert.Equal(t, value, newVal)
 }
 
+func TestKeyNotExist(t *testing.T) {
+	var (
+		s   = NewMemoryStore()
+		key = []byte("sparse")
+	)
+
+	_, err := s.Get(key)
+	assert.NotNil(t, err)
+	assert.Equal(t, err.Error(), "key not found")
+}
+
 func TestPutBatch(t *testing.T) {
 	var (
 		s     = NewMemoryStore()
diff --git a/pkg/core/storage/store.go b/pkg/core/storage/store.go
index 96e126dca..2d244fd9d 100644
--- a/pkg/core/storage/store.go
+++ b/pkg/core/storage/store.go
@@ -11,6 +11,7 @@ const (
 	DataTransaction   KeyPrefix = 0x02
 	STAccount         KeyPrefix = 0x40
 	STCoin            KeyPrefix = 0x44
+	STSpentCoin       KeyPrefix = 0x45
 	STValidator       KeyPrefix = 0x48
 	STAsset           KeyPrefix = 0x4c
 	STContract        KeyPrefix = 0x50
diff --git a/pkg/core/transaction/enrollment.go b/pkg/core/transaction/enrollment.go
new file mode 100644
index 000000000..f4295696d
--- /dev/null
+++ b/pkg/core/transaction/enrollment.go
@@ -0,0 +1,28 @@
+package transaction
+
+import (
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+)
+
+// A Enrollment transaction represents an enrollment form, which indicates
+// that the sponsor of the transaction would like to sign up as a validator.
+// The way to sign up is: To construct an EnrollmentTransaction type of transaction,
+// and send a deposit to the address of the PublicKey.
+// The way to cancel the registration is: Spend the deposit on the address of the PublicKey.
+type EnrollmentTX struct {
+	// PublicKey of the validator
+	PublicKey *crypto.PublicKey
+}
+
+// DecodeBinary implements the Payload interface.
+func (tx *EnrollmentTX) DecodeBinary(r io.Reader) error {
+	tx.PublicKey = &crypto.PublicKey{}
+	return tx.PublicKey.DecodeBinary(r)
+}
+
+// EncodeBinary implements the Payload interface.
+func (tx *EnrollmentTX) EncodeBinary(w io.Writer) error {
+	return tx.PublicKey.EncodeBinary(w)
+}
diff --git a/pkg/core/transaction/enrollment_test.go b/pkg/core/transaction/enrollment_test.go
new file mode 100644
index 000000000..b0d04b23f
--- /dev/null
+++ b/pkg/core/transaction/enrollment_test.go
@@ -0,0 +1,6 @@
+package transaction
+
+import "testing"
+
+func TestDecodeEncode(t *testing.T) {
+}
diff --git a/pkg/core/transaction/input.go b/pkg/core/transaction/input.go
index 8cee4645a..a4e2ce273 100644
--- a/pkg/core/transaction/input.go
+++ b/pkg/core/transaction/input.go
@@ -4,7 +4,7 @@ import (
 	"encoding/binary"
 	"io"
 
-	"github.com/anthdm/neo-go/pkg/util"
+	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
 // Input represents a Transaction input.
diff --git a/pkg/core/transaction/publish.go b/pkg/core/transaction/publish.go
new file mode 100644
index 000000000..50a95178c
--- /dev/null
+++ b/pkg/core/transaction/publish.go
@@ -0,0 +1,30 @@
+package transaction
+
+import (
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/smartcontract"
+)
+
+// PublishTX represents a publish transaction.
+// This is deprecated and should no longer be used.
+type PublishTX struct {
+	Script      []byte
+	ParamList   []smartcontract.ParamType
+	ReturnType  smartcontract.ParamType
+	NeedStorage bool
+	Name        string
+	Author      string
+	Email       string
+	Description string
+}
+
+// DecodeBinary implements the Payload interface.
+func (tx *PublishTX) DecodeBinary(r io.Reader) error {
+	return nil
+}
+
+// EncodeBinary implements the Payload interface.
+func (tx *PublishTX) EncodeBinary(w io.Writer) error {
+	return nil
+}
diff --git a/pkg/core/transaction/register.go b/pkg/core/transaction/register.go
index def4d023d..f7a6ccf60 100644
--- a/pkg/core/transaction/register.go
+++ b/pkg/core/transaction/register.go
@@ -29,7 +29,7 @@ import (
 // # 2. For currencies, use only unlimited models;
 // # 3. For point coupons, you can use any pattern;
 
-// RegisterTx represents a register transaction.
+// RegisterTX represents a register transaction.
 type RegisterTX struct {
 	// The type of the asset being registered.
 	AssetType AssetType
@@ -44,7 +44,9 @@ type RegisterTX struct {
 	// Decimals
 	Precision uint8
 
-	Owner crypto.EllipticCurvePoint
+	// Public key of the owner
+	Owner *crypto.PublicKey
+
 	Admin util.Uint160
 }
 
@@ -65,11 +67,10 @@ func (tx *RegisterTX) DecodeBinary(r io.Reader) error {
 		return err
 	}
 
-	point, err := crypto.NewEllipticCurvePointFromReader(r)
-	if err != nil {
+	tx.Owner = &crypto.PublicKey{}
+	if err := tx.Owner.DecodeBinary(r); err != nil {
 		return err
 	}
-	tx.Owner = point
 
 	return binary.Read(r, binary.LittleEndian, &tx.Admin)
 }
diff --git a/pkg/core/transaction/state.go b/pkg/core/transaction/state.go
new file mode 100644
index 000000000..3b61e7f84
--- /dev/null
+++ b/pkg/core/transaction/state.go
@@ -0,0 +1,29 @@
+package transaction
+
+import (
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// StateTX represents a state transaction.
+type StateTX struct {
+	Descriptors []*StateDescriptor
+}
+
+// DecodeBinary implements the Payload interface.
+func (tx *StateTX) DecodeBinary(r io.Reader) error {
+	lenDesc := util.ReadVarUint(r)
+	for i := 0; i < int(lenDesc); i++ {
+		tx.Descriptors[i] = &StateDescriptor{}
+		if err := tx.Descriptors[i].DecodeBinary(r); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// EncodeBinary implements the Payload interface.
+func (tx *StateTX) EncodeBinary(w io.Writer) error {
+	return nil
+}
diff --git a/pkg/core/transaction/state_descriptor.go b/pkg/core/transaction/state_descriptor.go
new file mode 100644
index 000000000..b45b250a3
--- /dev/null
+++ b/pkg/core/transaction/state_descriptor.go
@@ -0,0 +1,58 @@
+package transaction
+
+import (
+	"encoding/binary"
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// DescStateType represents the type of StateDescriptor.
+type DescStateType uint8
+
+// Valid DescStateType constants.
+const (
+	Account   DescStateType = 0x40
+	Validator DescStateType = 0x48
+)
+
+// StateDescriptor ..
+type StateDescriptor struct {
+	Type  DescStateType
+	Key   []byte
+	Value []byte
+	Field string
+}
+
+// DecodeBinary implements the Payload interface.
+func (s *StateDescriptor) DecodeBinary(r io.Reader) error {
+	if err := binary.Read(r, binary.LittleEndian, &s.Type); err != nil {
+		return err
+	}
+
+	keyLen := util.ReadVarUint(r)
+	s.Key = make([]byte, keyLen)
+	if err := binary.Read(r, binary.LittleEndian, s.Key); err != nil {
+		return err
+	}
+
+	valLen := util.ReadVarUint(r)
+	s.Value = make([]byte, valLen)
+	if err := binary.Read(r, binary.LittleEndian, s.Value); err != nil {
+		return err
+	}
+
+	fieldLen := util.ReadVarUint(r)
+	field := make([]byte, fieldLen)
+	if err := binary.Read(r, binary.LittleEndian, field); err != nil {
+		return err
+	}
+	s.Field = string(field)
+
+	return nil
+}
+
+// EncodeBinary implements the Payload interface.
+func (s *StateDescriptor) EncodeBinary(w io.Writer) error {
+	return nil
+}
diff --git a/pkg/core/transaction/transaction.go b/pkg/core/transaction/transaction.go
index 6f13d9f8b..7141ba342 100644
--- a/pkg/core/transaction/transaction.go
+++ b/pkg/core/transaction/transaction.go
@@ -147,6 +147,10 @@ func (t *Transaction) decodeData(r io.Reader) error {
 	case IssueType:
 		t.Data = &IssueTX{}
 		return t.Data.(*IssueTX).DecodeBinary(r)
+	case EnrollmentType:
+		t.Data = &EnrollmentTX{}
+		return t.Data.(*EnrollmentTX).DecodeBinary(r)
+
 	default:
 		log.Warnf("invalid TX type %s", t.Type)
 	}
@@ -180,8 +184,10 @@ func (t *Transaction) encodeHashableFields(w io.Writer) error {
 	}
 
 	// Underlying TXer.
-	if err := t.Data.EncodeBinary(w); err != nil {
-		return err
+	if t.Data != nil {
+		if err := t.Data.EncodeBinary(w); err != nil {
+			return err
+		}
 	}
 
 	// Attributes
@@ -230,3 +236,12 @@ func (t *Transaction) createHash() (hash util.Uint256, err error) {
 	b = sha.Sum(nil)
 	return util.Uint256DecodeBytes(util.ArrayReverse(b))
 }
+
+// GroupTXInputsByPrevHash groups all TX inputs by their previous hash.
+func (t *Transaction) GroupInputsByPrevHash() map[util.Uint256][]*Input {
+	m := make(map[util.Uint256][]*Input)
+	for _, in := range t.Inputs {
+		m[in.PrevHash] = append(m[in.PrevHash], in)
+	}
+	return m
+}
diff --git a/pkg/core/unspent_coin_state.go b/pkg/core/unspent_coin_state.go
new file mode 100644
index 000000000..53817be01
--- /dev/null
+++ b/pkg/core/unspent_coin_state.go
@@ -0,0 +1,81 @@
+package core
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// UnspentCoins is mapping between transactions and their unspent
+// coin state.
+type UnspentCoins map[util.Uint256]*UnspentCoinState
+
+func (u UnspentCoins) getAndChange(s storage.Store, hash util.Uint256) (*UnspentCoinState, error) {
+	if unspent, ok := u[hash]; ok {
+		return unspent, nil
+	}
+
+	var 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
+		}
+	} else {
+		unspent = &UnspentCoinState{
+			states: []CoinState{},
+		}
+	}
+
+	u[hash] = unspent
+	return unspent, nil
+}
+
+// UnspentCoinState hold the state of a unspent coin.
+type UnspentCoinState struct {
+	states []CoinState
+}
+
+// commit writes all unspent coin states to the given Batch.
+func (s UnspentCoins) commit(b storage.Batch) error {
+	buf := new(bytes.Buffer)
+	for hash, state := range s {
+		if err := state.EncodeBinary(buf); err != nil {
+			return err
+		}
+		key := storage.AppendPrefix(storage.STCoin, hash.BytesReverse())
+		b.Put(key, buf.Bytes())
+		buf.Reset()
+	}
+	return nil
+}
+
+// EncodeBinary encodes UnspentCoinState to the given io.Writer.
+func (s *UnspentCoinState) EncodeBinary(w io.Writer) error {
+	if err := util.WriteVarUint(w, uint64(len(s.states))); err != nil {
+		return err
+	}
+	for _, state := range s.states {
+		if err := binary.Write(w, binary.LittleEndian, byte(state)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// DecodBinary decodes UnspentCoinState from the given io.Reader.
+func (s *UnspentCoinState) DecodeBinary(r io.Reader) error {
+	lenStates := util.ReadVarUint(r)
+	s.states = make([]CoinState, lenStates)
+	for i := 0; i < int(lenStates); i++ {
+		var state uint8
+		if err := binary.Read(r, binary.LittleEndian, &state); err != nil {
+			return err
+		}
+		s.states[i] = CoinState(state)
+	}
+	return nil
+}
diff --git a/pkg/core/unspent_coint_state_test.go b/pkg/core/unspent_coint_state_test.go
new file mode 100644
index 000000000..b02d031a4
--- /dev/null
+++ b/pkg/core/unspent_coint_state_test.go
@@ -0,0 +1,59 @@
+package core
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDecodeEncode(t *testing.T) {
+	unspent := &UnspentCoinState{
+		states: []CoinState{
+			CoinStateConfirmed,
+			CoinStateSpent,
+			CoinStateSpent,
+			CoinStateSpent,
+			CoinStateConfirmed,
+		},
+	}
+
+	buf := new(bytes.Buffer)
+	assert.Nil(t, unspent.EncodeBinary(buf))
+	unspentDecode := &UnspentCoinState{}
+	assert.Nil(t, unspentDecode.DecodeBinary(buf))
+}
+
+func TestCommit(t *testing.T) {
+	var (
+		store        = storage.NewMemoryStore()
+		batch        = store.Batch()
+		unspentCoins = make(UnspentCoins)
+	)
+
+	txA := util.RandomUint256()
+	txB := util.RandomUint256()
+	txC := util.RandomUint256()
+
+	unspentCoins[txA] = &UnspentCoinState{
+		states: []CoinState{CoinStateConfirmed},
+	}
+	unspentCoins[txB] = &UnspentCoinState{
+		states: []CoinState{
+			CoinStateConfirmed,
+			CoinStateConfirmed,
+		},
+	}
+	unspentCoins[txC] = &UnspentCoinState{
+		states: []CoinState{
+			CoinStateConfirmed,
+			CoinStateConfirmed,
+			CoinStateConfirmed,
+		},
+	}
+
+	assert.Nil(t, unspentCoins.commit(batch))
+	assert.Nil(t, store.PutBatch(batch))
+}
diff --git a/pkg/core/util.go b/pkg/core/util.go
index faff23cd6..b5276f276 100644
--- a/pkg/core/util.go
+++ b/pkg/core/util.go
@@ -6,6 +6,7 @@ import (
 	"sort"
 
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
+	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
@@ -65,6 +66,22 @@ func storeAsBlock(batch storage.Batch, block *Block, sysFee uint32) error {
 	return nil
 }
 
+// storeAsTransaction stores the given TX as DataTransaction.
+func storeAsTransaction(batch storage.Batch, tx *transaction.Transaction, index uint32) error {
+	key := storage.AppendPrefix(storage.DataTransaction, tx.Hash().BytesReverse())
+	buf := new(bytes.Buffer)
+	if err := tx.EncodeBinary(buf); err != nil {
+		return err
+	}
+
+	dest := make([]byte, buf.Len()+4)
+	binary.LittleEndian.PutUint32(dest[:4], index)
+	copy(dest[4:], buf.Bytes())
+	batch.Put(key, dest)
+
+	return nil
+}
+
 // readStoredHeaderHashes returns a sorted list of header hashes
 // retrieved from the given Store.
 func readStoredHeaderHashes(store storage.Store) ([]util.Uint256, error) {
diff --git a/pkg/core/validator_state.go b/pkg/core/validator_state.go
new file mode 100644
index 000000000..f63bf2acf
--- /dev/null
+++ b/pkg/core/validator_state.go
@@ -0,0 +1,16 @@
+package core
+
+import (
+	"github.com/CityOfZion/neo-go/pkg/crypto"
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// Validators is a mapping between public keys and ValidatorState.
+type Validators map[*crypto.PublicKey]*ValidatorState
+
+// ValidatorState holds the state of a validator.
+type ValidatorState struct {
+	PublicKey  *crypto.PublicKey
+	Registered bool
+	Votes      util.Fixed8
+}
diff --git a/pkg/crypto/elliptic_curve.go b/pkg/crypto/elliptic_curve.go
index eaf4d46ce..cff138cb8 100644
--- a/pkg/crypto/elliptic_curve.go
+++ b/pkg/crypto/elliptic_curve.go
@@ -4,6 +4,8 @@ package crypto
 // Expanded and tweaked upon here under MIT license.
 
 import (
+	"bytes"
+	"crypto/rand"
 	"encoding/binary"
 	"encoding/hex"
 	"errors"
@@ -21,51 +23,18 @@ type (
 		A *big.Int
 		B *big.Int
 		P *big.Int
-		G EllipticCurvePoint
+		G ECPoint
 		N *big.Int
 		H *big.Int
 	}
 
-	// EllipticCurveEllipticCurvePoint represents a point on the EllipticCurve.
-	EllipticCurvePoint struct {
+	// ECPoint represents a point on the EllipticCurve.
+	ECPoint struct {
 		X *big.Int
 		Y *big.Int
 	}
 )
 
-// NewEllipticCurvePointFromReader return a new point from the given reader.
-// f == 4, 6 or 7 are not implemented.
-func NewEllipticCurvePointFromReader(r io.Reader) (point EllipticCurvePoint, err error) {
-	var f uint8
-	if err = binary.Read(r, binary.LittleEndian, &f); err != nil {
-		return
-	}
-
-	// Infinity
-	if f == 0 {
-		return EllipticCurvePoint{
-			X: new(big.Int),
-			Y: new(big.Int),
-		}, nil
-	}
-
-	if f == 2 || f == 3 {
-		y := new(big.Int).SetBytes([]byte{f & 1})
-		data := make([]byte, 32)
-		if err = binary.Read(r, binary.LittleEndian, data); err != nil {
-			return
-		}
-		data = util.ArrayReverse(data)
-		data = append(data, byte(0x00))
-
-		return EllipticCurvePoint{
-			X: new(big.Int).SetBytes(data),
-			Y: y,
-		}, nil
-	}
-	return
-}
-
 // NewEllipticCurve returns a ready to use EllipticCurve with preconfigured
 // fields for the NEO protocol.
 func NewEllipticCurve() EllipticCurve {
@@ -94,9 +63,84 @@ func NewEllipticCurve() EllipticCurve {
 	return c
 }
 
-func (p *EllipticCurvePoint) format() string {
-	if p.X == nil && p.Y == nil {
-		return "(inf,inf)"
+// RandomECPoint returns a random generated ECPoint, mostly used
+// for testing.
+func RandomECPoint() ECPoint {
+	c := NewEllipticCurve()
+	b := make([]byte, c.N.BitLen()/8+8)
+	if _, err := io.ReadFull(rand.Reader, b); err != nil {
+		return ECPoint{}
+	}
+
+	d := new(big.Int).SetBytes(b)
+	d.Mod(d, new(big.Int).Sub(c.N, big.NewInt(1)))
+	d.Add(d, big.NewInt(1))
+
+	q := new(big.Int).SetBytes(d.Bytes())
+	return c.ScalarBaseMult(q)
+}
+
+// ECPointFromReader return a new point from the given reader.
+// f == 4, 6 or 7 are not implemented.
+func ECPointFromReader(r io.Reader) (point ECPoint, err error) {
+	var f uint8
+	if err = binary.Read(r, binary.LittleEndian, &f); err != nil {
+		return
+	}
+
+	fmt.Println(f)
+
+	// Infinity
+	if f == 0 {
+		return ECPoint{
+			X: new(big.Int),
+			Y: new(big.Int),
+		}, nil
+	}
+
+	if f == 2 || f == 3 {
+		y := new(big.Int).SetBytes([]byte{f & 1})
+		data := make([]byte, 32)
+		if err = binary.Read(r, binary.LittleEndian, data); err != nil {
+			return
+		}
+		data = util.ArrayReverse(data)
+		data = append(data, byte(0x00))
+
+		return ECPoint{
+			X: new(big.Int).SetBytes(data),
+			Y: y,
+		}, nil
+	}
+	return
+}
+
+// EncodeBinary encodes the point to the given io.Writer.
+func (p ECPoint) EncodeBinary(w io.Writer) error {
+	bx := p.X.Bytes()
+	padded := append(
+		bytes.Repeat(
+			[]byte{0x00},
+			32-len(bx),
+		),
+		bx...,
+	)
+
+	prefix := byte(0x03)
+	if p.Y.Bit(0) == 0 {
+		prefix = byte(0x02)
+	}
+	buf := make([]byte, len(padded)+1)
+	buf[0] = prefix
+	copy(buf[1:], padded)
+
+	return binary.Write(w, binary.LittleEndian, buf)
+}
+
+// String implements the Stringer interface.
+func (p *ECPoint) String() string {
+	if p.IsInfinity() {
+		return "(inf, inf)"
 	}
 	bx := hex.EncodeToString(p.X.Bytes())
 	by := hex.EncodeToString(p.Y.Bytes())
@@ -104,15 +148,17 @@ func (p *EllipticCurvePoint) format() string {
 }
 
 // IsInfinity checks if point P is infinity on EllipticCurve ec.
-func (c *EllipticCurve) IsInfinity(P EllipticCurvePoint) bool {
-	if P.X == nil && P.Y == nil {
-		return true
-	}
-	return false
+func (p *ECPoint) IsInfinity() bool {
+	return p.X == nil && p.Y == nil
+}
+
+// IsInfinity checks if point P is infinity on EllipticCurve ec.
+func (c *EllipticCurve) IsInfinity(P ECPoint) bool {
+	return P.X == nil && P.Y == nil
 }
 
 // IsOnCurve checks if point P is on EllipticCurve ec.
-func (c *EllipticCurve) IsOnCurve(P EllipticCurvePoint) bool {
+func (c *EllipticCurve) IsOnCurve(P ECPoint) bool {
 	if c.IsInfinity(P) {
 		return false
 	}
@@ -130,7 +176,7 @@ func (c *EllipticCurve) IsOnCurve(P EllipticCurvePoint) bool {
 }
 
 // Add computes R = P + Q on EllipticCurve ec.
-func (c *EllipticCurve) Add(P, Q EllipticCurvePoint) (R EllipticCurvePoint) {
+func (c *EllipticCurve) Add(P, Q ECPoint) (R ECPoint) {
 	// See rules 1-5 on SEC1 pg.7 http://www.secg.org/collateral/sec1_final.pdf
 	if c.IsInfinity(P) && c.IsInfinity(Q) {
 		R.X = nil
@@ -172,18 +218,18 @@ func (c *EllipticCurve) Add(P, Q EllipticCurvePoint) (R EllipticCurvePoint) {
 				subMod(P.X, R.X, c.P), c.P),
 			P.Y, c.P)
 	} else {
-		panic(fmt.Sprintf("Unsupported point addition: %v + %v", P.format(), Q.format()))
+		panic(fmt.Sprintf("Unsupported point addition: %v + %v", P, Q))
 	}
 
 	return R
 }
 
 // ScalarMult computes Q = k * P on EllipticCurve ec.
-func (c *EllipticCurve) ScalarMult(k *big.Int, P EllipticCurvePoint) (Q EllipticCurvePoint) {
+func (c *EllipticCurve) ScalarMult(k *big.Int, P ECPoint) (Q ECPoint) {
 	// Implementation based on pseudocode here:
 	// https://en.wikipedia.org/wiki/Elliptic_curve_point_multiplication#Montgomery_ladder
-	var R0 EllipticCurvePoint
-	var R1 EllipticCurvePoint
+	var R0 ECPoint
+	var R1 ECPoint
 
 	R0.X = nil
 	R0.Y = nil
@@ -203,12 +249,12 @@ func (c *EllipticCurve) ScalarMult(k *big.Int, P EllipticCurvePoint) (Q Elliptic
 }
 
 // ScalarBaseMult computes Q = k * G on EllipticCurve ec.
-func (c *EllipticCurve) ScalarBaseMult(k *big.Int) (Q EllipticCurvePoint) {
+func (c *EllipticCurve) ScalarBaseMult(k *big.Int) (Q ECPoint) {
 	return c.ScalarMult(k, c.G)
 }
 
-// Decompress decompresses coordinate x and ylsb (y's least significant bit) into a EllipticCurvePoint P on EllipticCurve ec.
-func (c *EllipticCurve) Decompress(x *big.Int, ylsb uint) (P EllipticCurvePoint, err error) {
+// Decompress decompresses coordinate x and ylsb (y's least significant bit) into a ECPoint P on EllipticCurve ec.
+func (c *EllipticCurve) Decompress(x *big.Int, ylsb uint) (P ECPoint, err error) {
 	/* y**2 = x**3 + a*x + b  % p */
 	rhs := addMod(
 		addMod(
diff --git a/pkg/crypto/public_key.go b/pkg/crypto/public_key.go
new file mode 100644
index 000000000..e6f112579
--- /dev/null
+++ b/pkg/crypto/public_key.go
@@ -0,0 +1,68 @@
+package crypto
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"math/big"
+)
+
+// PublicKey represents a public key.
+type PublicKey struct {
+	ECPoint
+}
+
+// Bytes returns the byte array representation of the public key.
+func (p *PublicKey) Bytes() []byte {
+	var (
+		x       = p.X.Bytes()
+		paddedX = append(bytes.Repeat([]byte{0x00}, 32-len(x)), x...)
+		prefix  = byte(0x03)
+	)
+
+	if p.Y.Bit(0) == 0 {
+		prefix = byte(0x02)
+	}
+
+	return append([]byte{prefix}, paddedX...)
+}
+
+// DecodeBinary decodes a PublicKey from the given io.Reader.
+func (p *PublicKey) DecodeBinary(r io.Reader) error {
+	var prefix uint8
+	if err := binary.Read(r, binary.LittleEndian, &prefix); err != nil {
+		return err
+	}
+
+	// Compressed public keys.
+	if prefix == 0x02 || prefix == 0x03 {
+		c := NewEllipticCurve()
+		b := make([]byte, 32)
+		if err := binary.Read(r, binary.LittleEndian, b); err != nil {
+			return err
+		}
+
+		var err error
+		p.ECPoint, err = c.Decompress(new(big.Int).SetBytes(b), uint(prefix&0x1))
+		if err != nil {
+			return err
+		}
+	} else if prefix == 0x04 {
+		buf := make([]byte, 65)
+		if err := binary.Read(r, binary.LittleEndian, buf); err != nil {
+			return err
+		}
+		p.X = new(big.Int).SetBytes(buf[1:33])
+		p.Y = new(big.Int).SetBytes(buf[33:65])
+	} else {
+		return fmt.Errorf("invalid prefix %d", prefix)
+	}
+
+	return nil
+}
+
+// EncodeBinary encodes a PublicKey to the given io.Writer.
+func (p *PublicKey) EncodeBinary(w io.Writer) error {
+	return binary.Write(w, binary.LittleEndian, p.Bytes())
+}
diff --git a/pkg/crypto/public_key_test.go b/pkg/crypto/public_key_test.go
new file mode 100644
index 000000000..37e79e1f6
--- /dev/null
+++ b/pkg/crypto/public_key_test.go
@@ -0,0 +1,20 @@
+package crypto
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEncodeDecodePublicKey(t *testing.T) {
+	for i := 0; i < 4; i++ {
+		p := &PublicKey{RandomECPoint()}
+		buf := new(bytes.Buffer)
+		assert.Nil(t, p.EncodeBinary(buf))
+
+		pDecode := &PublicKey{}
+		assert.Nil(t, pDecode.DecodeBinary(buf))
+		assert.Equal(t, p.X, pDecode.X)
+	}
+}
diff --git a/pkg/util/test_util.go b/pkg/util/test_util.go
new file mode 100644
index 000000000..984bc60dc
--- /dev/null
+++ b/pkg/util/test_util.go
@@ -0,0 +1,45 @@
+package util
+
+import (
+	"crypto/sha256"
+	"math/rand"
+	"time"
+
+	"golang.org/x/crypto/ripemd160"
+)
+
+// RandomString returns a random string with the n as its length.
+func RandomString(n int) string {
+	b := make([]byte, n)
+	for i := range b {
+		b[i] = byte(RandomInt(65, 90))
+	}
+
+	return string(b)
+}
+
+// RamdomInt returns a ramdom integer betweeen min and max.
+func RandomInt(min, max int) int {
+	return min + rand.Intn(max-min)
+}
+
+// RandomUint256 returns a random Uint256.
+func RandomUint256() Uint256 {
+	str := RandomString(20)
+	h := sha256.Sum256([]byte(str))
+	return Uint256(h)
+}
+
+// RandomUint160 returns a random Uint160.
+func RandomUint160() Uint160 {
+	str := RandomString(20)
+	ripemd := ripemd160.New()
+	ripemd.Write([]byte(str))
+	h := ripemd.Sum(nil)
+	v, _ := Uint160DecodeBytes(h)
+	return v
+}
+
+func init() {
+	rand.Seed(time.Now().UTC().UnixNano())
+}