diff --git a/sm9/sm9_key.go b/sm9/sm9_key.go
index f2cc7ec..952cecd 100644
--- a/sm9/sm9_key.go
+++ b/sm9/sm9_key.go
@@ -16,8 +16,8 @@ import (
 
 // SignMasterPrivateKey master private key for sign, generated by KGC
 type SignMasterPrivateKey struct {
-	SignMasterPublicKey          // master public key
-	D                   *big.Int // master private key
+	*SignMasterPublicKey          // master public key
+	D                    *big.Int // master private key
 }
 
 // SignMasterPublicKey master public key for sign, generated by KGC
@@ -31,14 +31,14 @@ type SignMasterPublicKey struct {
 
 // SignPrivateKey user private key for sign, generated by KGC
 type SignPrivateKey struct {
-	PrivateKey          *bn256.G1 // user private key
-	SignMasterPublicKey           // master public key
+	PrivateKey           *bn256.G1 // user private key
+	*SignMasterPublicKey           // master public key
 }
 
 // EncryptMasterPrivateKey master private key for encryption, generated by KGC
 type EncryptMasterPrivateKey struct {
-	EncryptMasterPublicKey          // master public key
-	D                      *big.Int // master private key
+	*EncryptMasterPublicKey          // master public key
+	D                       *big.Int // master private key
 }
 
 // EncryptMasterPublicKey master private key for encryption, generated by KGC
@@ -52,8 +52,8 @@ type EncryptMasterPublicKey struct {
 
 // EncryptPrivateKey user private key for encryption, generated by KGC
 type EncryptPrivateKey struct {
-	PrivateKey             *bn256.G2 // user private key
-	EncryptMasterPublicKey           // master public key
+	PrivateKey              *bn256.G2 // user private key
+	*EncryptMasterPublicKey           // master public key
 }
 
 // GenerateSignMasterKey generates a master public and private key pair for DSA usage.
@@ -70,6 +70,7 @@ func GenerateSignMasterKey(rand io.Reader) (*SignMasterPrivateKey, error) {
 
 	priv := new(SignMasterPrivateKey)
 	priv.D = new(big.Int).SetBytes(kBytes)
+	priv.SignMasterPublicKey = new(SignMasterPublicKey)
 	priv.MasterPublicKey = p
 	return priv, nil
 }
@@ -102,6 +103,7 @@ func (master *SignMasterPrivateKey) UnmarshalASN1(der []byte) error {
 		return errors.New("sm9: invalid sign master private key asn1 data")
 	}
 	master.D = d
+	master.SignMasterPublicKey = new(SignMasterPublicKey)
 	p, err := new(bn256.G2).ScalarBaseMult(bn256.NormalizeScalar(d.Bytes()))
 	if err != nil {
 		return err
@@ -144,7 +146,7 @@ func (master *SignMasterPrivateKey) GenerateUserKey(uid []byte, hid byte) (*Sign
 
 // Public returns the public key corresponding to priv.
 func (master *SignMasterPrivateKey) Public() *SignMasterPublicKey {
-	return &master.SignMasterPublicKey
+	return master.SignMasterPublicKey
 }
 
 // pair generate the basepoint once
@@ -257,13 +259,13 @@ func (pub *SignMasterPublicKey) ParseFromPEM(data []byte) error {
 
 // MasterPublic returns the master public key corresponding to priv.
 func (priv *SignPrivateKey) MasterPublic() *SignMasterPublicKey {
-	return &priv.SignMasterPublicKey
+	return priv.SignMasterPublicKey
 }
 
 // SetMasterPublicKey bind the sign master public key to it.
 func (priv *SignPrivateKey) SetMasterPublicKey(pub *SignMasterPublicKey) {
 	if priv.SignMasterPublicKey.MasterPublicKey == nil {
-		priv.SignMasterPublicKey = *pub
+		priv.SignMasterPublicKey = pub
 	}
 }
 
@@ -357,6 +359,7 @@ func GenerateEncryptMasterKey(rand io.Reader) (*EncryptMasterPrivateKey, error)
 
 	priv := new(EncryptMasterPrivateKey)
 	priv.D = new(big.Int).SetBytes(kBytes)
+	priv.EncryptMasterPublicKey = new(EncryptMasterPublicKey)
 	p, err := new(bn256.G1).ScalarBaseMult(kBytes)
 	if err != nil {
 		panic(err)
@@ -399,7 +402,7 @@ func (master *EncryptMasterPrivateKey) GenerateUserKey(uid []byte, hid byte) (*E
 
 // Public returns the public key corresponding to priv.
 func (master *EncryptMasterPrivateKey) Public() *EncryptMasterPublicKey {
-	return &master.EncryptMasterPublicKey
+	return master.EncryptMasterPublicKey
 }
 
 // MarshalASN1 marshal encrypt master private key to asn.1 format data according
@@ -430,6 +433,7 @@ func (master *EncryptMasterPrivateKey) UnmarshalASN1(der []byte) error {
 		return errors.New("sm9: invalid encrypt master private key asn1 data")
 	}
 	master.D = d
+	master.EncryptMasterPublicKey = new(EncryptMasterPublicKey)
 	p, err := new(bn256.G1).ScalarBaseMult(bn256.NormalizeScalar(d.Bytes()))
 	if err != nil {
 		return err
@@ -529,13 +533,13 @@ func (pub *EncryptMasterPublicKey) UnmarshalASN1(der []byte) error {
 
 // MasterPublic returns the master public key corresponding to priv.
 func (priv *EncryptPrivateKey) MasterPublic() *EncryptMasterPublicKey {
-	return &priv.EncryptMasterPublicKey
+	return priv.EncryptMasterPublicKey
 }
 
 // SetMasterPublicKey bind the encrypt master public key to it.
 func (priv *EncryptPrivateKey) SetMasterPublicKey(pub *EncryptMasterPublicKey) {
 	if priv.EncryptMasterPublicKey.MasterPublicKey == nil {
-		priv.EncryptMasterPublicKey = *pub
+		priv.EncryptMasterPublicKey = pub
 	}
 }