diff --git a/sm9/bn256/bn_pair_test.go b/sm9/bn256/bn_pair_test.go
index cb1eb95..5a60baf 100644
--- a/sm9/bn256/bn_pair_test.go
+++ b/sm9/bn256/bn_pair_test.go
@@ -162,6 +162,20 @@ func BenchmarkFinalExponentiation(b *testing.B) {
 	}
 }
 
+func BenchmarkMiller(b *testing.B) {
+	pk := bigFromHex("0130E78459D78545CB54C587E02CF480CE0B66340F319F348A1D5B1F2DC5F4")
+	g2 := &G2{}
+	_, err := g2.ScalarBaseMult(NormalizeScalar(pk.Bytes()))
+	if err != nil {
+		b.Fatal(err)
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		miller(g2.p, curveGen)
+	}
+}
+
 func BenchmarkPairingB4(b *testing.B) {
 	pk := bigFromHex("0130E78459D78545CB54C587E02CF480CE0B66340F319F348A1D5B1F2DC5F4")
 	g2 := &G2{}
diff --git a/sm9/bn256/twist.go b/sm9/bn256/twist.go
index a2c99e9..980de15 100644
--- a/sm9/bn256/twist.go
+++ b/sm9/bn256/twist.go
@@ -58,7 +58,7 @@ func NewTwistGenerator() *twistPoint {
 
 func (c *twistPoint) polynomial(x *gfP2) *gfP2 {
 	x3 := &gfP2{}
-	x3.Square(x).Mul(x3, x).Add(x3, twistB)
+	x3.SquareNC(x).Mul(x3, x).Add(x3, twistB)
 	return x3
 }
 
@@ -70,7 +70,7 @@ func (c *twistPoint) IsOnCurve() bool {
 	}
 
 	y2 := &gfP2{}
-	y2.Square(&c.y)
+	y2.SquareNC(&c.y)
 	x3 := c.polynomial(&c.x)
 
 	return *y2 == *x3