diff --git a/wallet/nockhash.go b/wallet/nockhash.go
index d6b79da..70023f1 100644
--- a/wallet/nockhash.go
+++ b/wallet/nockhash.go
@@ -1,6 +1,7 @@
 package wallet
 
 import (
+	"fmt"
 	"math/big"
 
 	"github.com/btcsuite/btcd/btcutil/base58"
@@ -152,23 +153,6 @@ func HashSource(source *nockchain.NockchainSource) [5]uint64 {
 	}
 }
 
-func HashParent(note *nockchain.NockchainNote) ([5]uint64, error) {
-	nameHash := HashName(note.Name)
-	lockHash, err := HashLock(note.Lock)
-	if err != nil {
-		return [5]uint64{}, err
-	}
-
-	sourceHash := HashSource(note.Source)
-	assetHash := crypto.Tip5HashBelts([]crypto.Belt{{Value: 1}, {Value: uint64(note.Asset)}})
-
-	hashSourceAsset := crypto.Tip5RehashTenCell(sourceHash, assetHash)
-
-	q := crypto.Tip5RehashTenCell(nameHash, crypto.Tip5RehashTenCell(lockHash, hashSourceAsset))
-
-	return q, nil
-}
-
 func HashSeedWithoutSource(seed *nockchain.NockchainSeed) ([5]uint64, error) {
 	lockHash, err := HashLock(seed.Recipient)
 	if err != nil {
@@ -214,6 +198,10 @@ func HashNonce(pkPoint crypto.CheetahPoint, message [5]uint64) ([]crypto.Belt, [
 
 func HashSpend(spend *nockchain.NockchainSpend) ([5]uint64, error) {
 	// TODO: handle multiple sig
+	if len(spend.Signatures) == 0 {
+		return [5]uint64{}, fmt.Errorf("signatures can not be empty")
+	}
+
 	sigHash, err := HashSignature(spend.Signatures[0])
 	if err != nil {
 		return [5]uint64{}, err
@@ -386,13 +374,16 @@ func ParseBalanceEntry(entry *nockchain.BalanceEntry) nockchain.NockchainNote {
 		},
 		Source: &nockchain.NockchainSource{
 			Source:     crypto.Tip5HashToBase58(sourceHash),
-			IsCoinbase: entry.Note.Source.Coinbase,
+			IsCoinbase: true,
 		},
 		Asset: entry.Note.Assets.Value,
 	}
 }
 
 func ParseTimelockIntent(timelock *nockchain.TimeLockIntent) *nockchain.TimelockIntent {
+	if timelock == nil {
+		return nil
+	}
 	switch timelock.Value.(type) {
 	case *nockchain.TimeLockIntent_Absolute:
 		return &nockchain.TimelockIntent{
diff --git a/wallet/service.go b/wallet/service.go
index 417b0f8..ebde3df 100644
--- a/wallet/service.go
+++ b/wallet/service.go
@@ -331,20 +331,11 @@ func (h *GprcHandler) CreateTx(ctx context.Context, req *nockchain.CreateTxReque
 	var masterKey *crypto.MasterKey
 	chainCode := base58.Decode(req.ChainCode)
 	key := base58.Decode(req.Key)
-	_, err := crypto.CheetaPointFromBytes(key)
+	masterKey, err := crypto.MasterKeyFromPrivKey(chainCode, key)
 	if err != nil {
-		// priv key
-		masterKey, err = crypto.MasterKeyFromPrivKey(chainCode, key)
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		masterKey = &crypto.MasterKey{
-			PrivateKey: []byte{},
-			PublicKey:  key,
-			ChainCode:  chainCode,
-		}
+		return nil, err
 	}
+
 	if !req.IsMasterKey {
 		index := req.Index
 		if index > 1<<32 {
@@ -399,7 +390,7 @@ func (h *GprcHandler) CreateTx(ctx context.Context, req *nockchain.CreateTxReque
 			return nil, fmt.Errorf("note not enough balance")
 		}
 
-		parentHash, err := HashParent(notes[i])
+		parentHash, err := HashNote(notes[i])
 		if err != nil {
 			return nil, err
 		}
@@ -437,20 +428,18 @@ func (h *GprcHandler) CreateTx(ctx context.Context, req *nockchain.CreateTxReque
 			return nil, err
 		}
 
-		if len(masterKey.PrivateKey) != 0 {
-			// sign
-			chalT8, sigT8, err := ComputeSig(*masterKey, msg)
-			if err != nil {
-				return nil, err
-			}
+		// sign
+		chalT8, sigT8, err := ComputeSig(*masterKey, msg)
+		if err != nil {
+			return nil, err
+		}
 
-			spend.Signatures = []*nockchain.NockchainSignature{
-				{
-					Pubkey: base58.Encode(masterKey.PublicKey),
-					Chal:   chalT8[:],
-					Sig:    sigT8[:],
-				},
-			}
+		spend.Signatures = []*nockchain.NockchainSignature{
+			{
+				Pubkey: base58.Encode(masterKey.PublicKey),
+				Chal:   chalT8[:],
+				Sig:    sigT8[:],
+			},
 		}
 
 		input := nockchain.NockchainInput{