diff --git a/sm2/sm2.go b/sm2/sm2.go
index 2f3eea4..bbd13ff 100644
--- a/sm2/sm2.go
+++ b/sm2/sm2.go
@@ -250,6 +250,17 @@ func calculateC3(curve elliptic.Curve, x2, y2 *big.Int, msg []byte) []byte {
 	return md.Sum(nil)
 }
 
+func mashalASN1Ciphertext(x1, y1 *big.Int, c2, c3 []byte) ([]byte, error) {
+	var b cryptobyte.Builder
+	b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
+		b.AddASN1BigInt(x1)
+		b.AddASN1BigInt(y1)
+		b.AddASN1OctetString(c3)
+		b.AddASN1OctetString(c2)
+	})
+	return b.Bytes()
+}
+
 // sm2 encrypt and output ASN.1 result
 func EncryptASN1(random io.Reader, pub *ecdsa.PublicKey, msg []byte) ([]byte, error) {
 	return Encrypt(random, pub, msg, ASN1EncrypterOpts)
@@ -310,16 +321,9 @@ func Encrypt(random io.Reader, pub *ecdsa.PublicKey, msg []byte, opts *Encrypter
 			}
 			// c1 || c2 || c3
 			return append(append(c1, c2...), c3...), nil
-		} else { // ASN.1 format will force C3 C2 order
-			var b cryptobyte.Builder
-			b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
-				b.AddASN1BigInt(x1)
-				b.AddASN1BigInt(y1)
-				b.AddASN1OctetString(c3)
-				b.AddASN1OctetString(c2)
-			})
-			return b.Bytes()
 		}
+		// ASN.1 format will force C3 C2 order
+		return mashalASN1Ciphertext(x1, y1, c2, c3)
 	}
 }
 
@@ -344,20 +348,9 @@ func Decrypt(priv *PrivateKey, ciphertext []byte) ([]byte, error) {
 }
 
 func decryptASN1(priv *PrivateKey, ciphertext []byte) ([]byte, error) {
-	var (
-		x1, y1 = &big.Int{}, &big.Int{}
-		c2, c3 []byte
-		inner  cryptobyte.String
-	)
-	input := cryptobyte.String(ciphertext)
-	if !input.ReadASN1(&inner, asn1.SEQUENCE) ||
-		!input.Empty() ||
-		!inner.ReadASN1Integer(x1) ||
-		!inner.ReadASN1Integer(y1) ||
-		!inner.ReadASN1Bytes(&c3, asn1.OCTET_STRING) ||
-		!inner.ReadASN1Bytes(&c2, asn1.OCTET_STRING) ||
-		!inner.Empty() {
-		return nil, errors.New("SM2: invalid asn1 format ciphertext")
+	x1, y1, c2, c3, err := unmarshalASN1Ciphertext(ciphertext)
+	if err != nil {
+		return nil, err
 	}
 	return rawDecrypt(priv, x1, y1, c2, c3)
 }
@@ -420,11 +413,7 @@ func decrypt(priv *PrivateKey, ciphertext []byte, opts *DecrypterOpts) ([]byte,
 	return rawDecrypt(priv, x1, y1, c2, c3)
 }
 
-// utility method to convert ASN.1 encoding ciphertext to plain encoding format
-func ASN1Ciphertext2Plain(ciphertext []byte, opts *EncrypterOpts) ([]byte, error) {
-	if opts == nil {
-		opts = defaultEncrypterOpts
-	}
+func unmarshalASN1Ciphertext(ciphertext []byte) (*big.Int, *big.Int, []byte, []byte, error) {
 	var (
 		x1, y1 = &big.Int{}, &big.Int{}
 		c2, c3 []byte
@@ -438,7 +427,19 @@ func ASN1Ciphertext2Plain(ciphertext []byte, opts *EncrypterOpts) ([]byte, error
 		!inner.ReadASN1Bytes(&c3, asn1.OCTET_STRING) ||
 		!inner.ReadASN1Bytes(&c2, asn1.OCTET_STRING) ||
 		!inner.Empty() {
-		return nil, errors.New("SM2: invalid asn1 format ciphertext")
+		return nil, nil, nil, nil, errors.New("SM2: invalid asn1 format ciphertext")
+	}
+	return x1, y1, c2, c3, nil
+}
+
+// ASN1Ciphertext2Plain utility method to convert ASN.1 encoding ciphertext to plain encoding format
+func ASN1Ciphertext2Plain(ciphertext []byte, opts *EncrypterOpts) ([]byte, error) {
+	if opts == nil {
+		opts = defaultEncrypterOpts
+	}
+	x1, y1, c2, c3, err := unmarshalASN1Ciphertext((ciphertext))
+	if err != nil {
+		return nil, err
 	}
 	curve := P256()
 	c1 := opts.PointMarshalMode.mashal(curve, x1, y1)
@@ -450,7 +451,7 @@ func ASN1Ciphertext2Plain(ciphertext []byte, opts *EncrypterOpts) ([]byte, error
 	return append(append(c1, c2...), c3...), nil
 }
 
-// utility method to convert plain encoding ciphertext to ASN.1 encoding format
+// PlainCiphertext2ASN1 utility method to convert plain encoding ciphertext to ASN.1 encoding format
 func PlainCiphertext2ASN1(ciphertext []byte, from ciphertextSplicingOrder) ([]byte, error) {
 	if ciphertext[0] == 0x30 {
 		return nil, errors.New("SM2: invalid plain encoding ciphertext")
@@ -475,17 +476,10 @@ func PlainCiphertext2ASN1(ciphertext []byte, from ciphertextSplicingOrder) ([]by
 		c2 = ciphertext[c3Start : ciphertextLen-sm3.Size]
 		c3 = ciphertext[ciphertextLen-sm3.Size:]
 	}
-	var b cryptobyte.Builder
-	b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
-		b.AddASN1BigInt(x1)
-		b.AddASN1BigInt(y1)
-		b.AddASN1OctetString(c3)
-		b.AddASN1OctetString(c2)
-	})
-	return b.Bytes()
+	return mashalASN1Ciphertext(x1, y1, c2, c3)
 }
 
-// utility method
+// AdjustCiphertextSplicingOrder utility method to change c2 c3 order
 func AdjustCiphertextSplicingOrder(ciphertext []byte, from, to ciphertextSplicingOrder) ([]byte, error) {
 	curve := P256()
 	if from == to {
diff --git a/sm2/sm2_test.go b/sm2/sm2_test.go
index 545c342..00bb930 100644
--- a/sm2/sm2_test.go
+++ b/sm2/sm2_test.go
@@ -83,7 +83,7 @@ func Test_encryptDecrypt_ASN1(t *testing.T) {
 		plainText string
 	}{
 		// TODO: Add test cases.
-		{"less than 32", "emmansun"},
+		{"less than 32", "encryption standard"},
 		{"equals 32", "encryption standard encryption "},
 		{"long than 32", "encryption standard encryption standard"},
 	}
@@ -112,7 +112,7 @@ func Test_Ciphertext2ASN1(t *testing.T) {
 		plainText string
 	}{
 		// TODO: Add test cases.
-		{"less than 32", "emmansun"},
+		{"less than 32", "encryption standard"},
 		{"equals 32", "encryption standard encryption "},
 		{"long than 32", "encryption standard encryption standard"},
 	}
@@ -144,7 +144,7 @@ func Test_ASN1Ciphertext2Plain(t *testing.T) {
 		plainText string
 	}{
 		// TODO: Add test cases.
-		{"less than 32", "emmansun"},
+		{"less than 32", "encryption standard"},
 		{"equals 32", "encryption standard encryption "},
 		{"long than 32", "encryption standard encryption standard"},
 	}
diff --git a/smx509/x509_test.go b/smx509/x509_test.go
index 74920fc..754429f 100644
--- a/smx509/x509_test.go
+++ b/smx509/x509_test.go
@@ -264,30 +264,26 @@ func TestSignByHuaweiVerifyAtLocal(t *testing.T) {
 	}
 }
 
-func TestParsePKIXPublicKey(t *testing.T) {
-	pub, err := getPublicKey([]byte(publicKeyPemFromAliKms))
-	if err != nil {
-		t.Fatal(err)
+func TestParsePKIXPublicKeyFromExternal(t *testing.T) {
+	tests := []struct {
+		name string
+		pem  string
+	}{
+		{"ALI", publicKeyPemFromAliKms},
+		{"HUAWEI", publicKeyPemFromHuaweiKms},
 	}
-	pub1 := pub.(*ecdsa.PublicKey)
-	encrypted, err := sm2.Encrypt(rand.Reader, pub1, []byte("testfile"), nil)
-	if err != nil {
-		t.Fatal(err)
+	for _, test := range tests {
+		pub, err := getPublicKey([]byte(test.pem))
+		if err != nil {
+			t.Fatalf("%s failed to get public key %v", test.name, err)
+		}
+		pub1 := pub.(*ecdsa.PublicKey)
+		encrypted, err := sm2.Encrypt(rand.Reader, pub1, []byte("encryption standard"), sm2.ASN1EncrypterOpts)
+		if err != nil {
+			t.Fatalf("%s failed to encrypt %v", test.name, err)
+		}
+		fmt.Printf("encrypted=%s\n", base64.RawURLEncoding.EncodeToString(encrypted))
 	}
-	fmt.Printf("encrypted=%s\n", base64.StdEncoding.EncodeToString(encrypted))
-}
-
-func TestParsePKIXPublicKeyFromHuawei(t *testing.T) {
-	pub, err := getPublicKey([]byte(publicKeyPemFromHuaweiKms))
-	if err != nil {
-		t.Fatal(err)
-	}
-	pub1 := pub.(*ecdsa.PublicKey)
-	encrypted, err := sm2.Encrypt(rand.Reader, pub1, []byte("encryption standard"), sm2.ASN1EncrypterOpts)
-	if err != nil {
-		t.Fatal(err)
-	}
-	fmt.Printf("encrypted=%s\n", base64.RawURLEncoding.EncodeToString(encrypted))
 }
 
 func TestMarshalPKIXPublicKey(t *testing.T) {