diff --git a/sm2/sm2.go b/sm2/sm2.go
index 2594e49..aba13ac 100644
--- a/sm2/sm2.go
+++ b/sm2/sm2.go
@@ -136,7 +136,7 @@ func bytes2Point(curve elliptic.Curve, bytes []byte) (*big.Int, *big.Int, int, e
 		data := make([]byte, 1+byteLen*2)
 		data[0] = uncompressed
 		copy(data[1:], bytes[1:1+byteLen*2])
-		x, y := elliptic.Unmarshal(curve, data)
+		x, y := sm2ec.Unmarshal(curve, data)
 		if x == nil || y == nil {
 			return nil, nil, 0, fmt.Errorf("sm2: point is not on curve %s", curve.Params().Name)
 		}
@@ -148,7 +148,7 @@ func bytes2Point(curve elliptic.Curve, bytes []byte) (*big.Int, *big.Int, int, e
 		// Make sure it's NIST curve or SM2 P-256 curve
 		if strings.HasPrefix(curve.Params().Name, "P-") || strings.EqualFold(curve.Params().Name, sm2ec.P256().Params().Name) {
 			// y² = x³ - 3x + b, prime curves
-			x, y := elliptic.UnmarshalCompressed(curve, bytes[:1+byteLen])
+			x, y := sm2ec.UnmarshalCompressed(curve, bytes[:1+byteLen])
 			if x == nil || y == nil {
 				return nil, nil, 0, fmt.Errorf("sm2: point is not on curve %s", curve.Params().Name)
 			}
diff --git a/sm2/sm2ec/elliptic.go b/sm2/sm2ec/elliptic.go
index e34e6c5..b0c92a6 100644
--- a/sm2/sm2ec/elliptic.go
+++ b/sm2/sm2ec/elliptic.go
@@ -34,3 +34,29 @@ func P256() elliptic.Curve {
 	initonce.Do(initAll)
 	return sm2p256
 }
+
+// Since golang 1.19
+// unmarshaler is implemented by curves with their own constant-time Unmarshal.
+// There isn't an equivalent interface for Marshal/MarshalCompressed because
+// that doesn't involve any mathematical operations, only FillBytes and Bit.
+type unmarshaler interface {
+	Unmarshal([]byte) (x, y *big.Int)
+	UnmarshalCompressed([]byte) (x, y *big.Int)
+}
+
+func Unmarshal(curve elliptic.Curve, data []byte) (x, y *big.Int) {
+	if c, ok := curve.(unmarshaler); ok {
+		return c.Unmarshal(data)
+	}
+	return elliptic.Unmarshal(curve, data)
+}
+
+// UnmarshalCompressed converts a point, serialized by MarshalCompressed, into
+// an x, y pair. It is an error if the point is not in compressed form, is not
+// on the curve, or is the point at infinity. On error, x = nil.
+func UnmarshalCompressed(curve elliptic.Curve, data []byte) (x, y *big.Int) {
+	if c, ok := curve.(unmarshaler); ok {
+		return c.UnmarshalCompressed(data)
+	}
+	return elliptic.UnmarshalCompressed(curve, data)
+}
diff --git a/sm2/sm2ec/elliptic_test.go b/sm2/sm2ec/elliptic_test.go
index 760ec2f..a084c25 100644
--- a/sm2/sm2ec/elliptic_test.go
+++ b/sm2/sm2ec/elliptic_test.go
@@ -11,32 +11,6 @@ import (
 
 var _ = elliptic.P256() // force NIST P curves init, avoid panic when we invoke generic implementation's method
 
-// unmarshaler is implemented by curves with their own constant-time Unmarshal.
-// Since golang 1.19
-// There isn't an equivalent interface for Marshal/MarshalCompressed because
-// that doesn't involve any mathematical operations, only FillBytes and Bit.
-type unmarshaler interface {
-	Unmarshal([]byte) (x, y *big.Int)
-	UnmarshalCompressed([]byte) (x, y *big.Int)
-}
-
-func unmarshal(curve elliptic.Curve, data []byte) (x, y *big.Int) {
-	if c, ok := curve.(unmarshaler); ok {
-		return c.Unmarshal(data)
-	}
-	return elliptic.Unmarshal(curve, data)
-}
-
-// UnmarshalCompressed converts a point, serialized by MarshalCompressed, into
-// an x, y pair. It is an error if the point is not in compressed form, is not
-// on the curve, or is the point at infinity. On error, x = nil.
-func unmarshalCompressed(curve elliptic.Curve, data []byte) (x, y *big.Int) {
-	if c, ok := curve.(unmarshaler); ok {
-		return c.UnmarshalCompressed(data)
-	}
-	return elliptic.UnmarshalCompressed(curve, data)
-}
-
 // genericParamsForCurve returns the dereferenced CurveParams for
 // the specified curve. This is used to avoid the logic for
 // upgrading a curve to its specific implementation, forcing
@@ -87,7 +61,7 @@ func TestOffCurve(t *testing.T) {
 		x.FillBytes(b[1 : 1+byteLen])
 		y.FillBytes(b[1+byteLen : 1+2*byteLen])
 
-		x1, y1 := unmarshal(curve, b)
+		x1, y1 := Unmarshal(curve, b)
 		if x1 != nil || y1 != nil {
 			t.Errorf("unmarshaling a point not on the curve succeeded")
 		}
@@ -152,18 +126,18 @@ func testInfinity(t *testing.T, curve elliptic.Curve) {
 		t.Errorf("IsOnCurve(∞) == true")
 	}
 
-	if xx, yy := unmarshal(curve, elliptic.Marshal(curve, x0, y0)); xx != nil || yy != nil {
+	if xx, yy := Unmarshal(curve, elliptic.Marshal(curve, x0, y0)); xx != nil || yy != nil {
 		t.Errorf("Unmarshal(Marshal(∞)) did not return an error")
 	}
 	// We don't test UnmarshalCompressed(MarshalCompressed(∞)) because there are
 	// two valid points with x = 0.
-	if xx, yy := unmarshal(curve, []byte{0x00}); xx != nil || yy != nil {
+	if xx, yy := Unmarshal(curve, []byte{0x00}); xx != nil || yy != nil {
 		t.Errorf("Unmarshal(∞) did not return an error")
 	}
 	byteLen := (curve.Params().BitSize + 7) / 8
 	buf := make([]byte, byteLen*2+1)
 	buf[0] = 4 // Uncompressed format.
-	if xx, yy := unmarshal(curve, buf); xx != nil || yy != nil {
+	if xx, yy := Unmarshal(curve, buf); xx != nil || yy != nil {
 		t.Errorf("Unmarshal((0,0)) did not return an error")
 	}
 }
@@ -175,7 +149,7 @@ func TestMarshal(t *testing.T) {
 			t.Fatal(err)
 		}
 		serialized := elliptic.Marshal(curve, x, y)
-		xx, yy := unmarshal(curve, serialized)
+		xx, yy := Unmarshal(curve, serialized)
 		if xx == nil {
 			t.Fatal("failed to unmarshal")
 		}
@@ -256,7 +230,7 @@ func TestMarshalCompressed(t *testing.T) {
 
 	t.Run("Invalid", func(t *testing.T) {
 		data, _ := hex.DecodeString("02fd4bf61763b46581fd9174d623516cf3c81edd40e29ffa2777fb6cb0ae3ce535")
-		X, Y := unmarshalCompressed(P256(), data)
+		X, Y := UnmarshalCompressed(P256(), data)
 		if X != nil || Y != nil {
 			t.Error("expected an error for invalid encoding")
 		}
@@ -284,7 +258,7 @@ func testMarshalCompressed(t *testing.T, curve elliptic.Curve, x, y *big.Int, wa
 		t.Errorf("got unexpected MarshalCompressed result: got %x, want %x", got, want)
 	}
 
-	X, Y := unmarshalCompressed(curve, got)
+	X, Y := UnmarshalCompressed(curve, got)
 	if X == nil || Y == nil {
 		t.Fatalf("UnmarshalCompressed failed unexpectedly")
 	}
@@ -354,7 +328,7 @@ func BenchmarkMarshalUnmarshal(b *testing.B) {
 			b.ReportAllocs()
 			for i := 0; i < b.N; i++ {
 				buf := elliptic.Marshal(curve, x, y)
-				xx, yy := unmarshal(curve, buf)
+				xx, yy := Unmarshal(curve, buf)
 				if xx.Cmp(x) != 0 || yy.Cmp(y) != 0 {
 					b.Error("Unmarshal output different from Marshal input")
 				}
@@ -364,7 +338,7 @@ func BenchmarkMarshalUnmarshal(b *testing.B) {
 			b.ReportAllocs()
 			for i := 0; i < b.N; i++ {
 				buf := elliptic.MarshalCompressed(curve, x, y)
-				xx, yy := unmarshalCompressed(curve, buf)
+				xx, yy := UnmarshalCompressed(curve, buf)
 				if xx.Cmp(x) != 0 || yy.Cmp(y) != 0 {
 					b.Error("Unmarshal output different from Marshal input")
 				}