diff --git a/ecc/bls12381/g1.go b/ecc/bls12381/g1.go
index 5ecc5873..7ad21194 100644
--- a/ecc/bls12381/g1.go
+++ b/ecc/bls12381/g1.go
@@ -392,7 +392,8 @@ func G1Generator() *G1 {
 }
 
 // affinize converts an entire slice to affine at once
-func affinize(points []*G1) {
+func affinize(points []*G1) (out []G1) {
+	out = make([]G1, len(points))
 	if len(points) == 0 {
 		return
 	}
@@ -410,8 +411,9 @@ func affinize(points []*G1) {
 		zinv.Mul(w, &ws[i])
 		w.Mul(w, &points[i].z)
 
-		points[i].x.Mul(&points[i].x, zinv)
-		points[i].y.Mul(&points[i].y, zinv)
-		points[i].z.SetOne()
+		out[i].x.Mul(&points[i].x, zinv)
+		out[i].y.Mul(&points[i].y, zinv)
+		out[i].z.SetOne()
 	}
+	return
 }
diff --git a/ecc/bls12381/g1_test.go b/ecc/bls12381/g1_test.go
index 2f85211f..cb601176 100644
--- a/ecc/bls12381/g1_test.go
+++ b/ecc/bls12381/g1_test.go
@@ -218,17 +218,14 @@ func TestG1Affinize(t *testing.T) {
 	N := 20
 	testTimes := 1 << 6
 	g1 := make([]*G1, N)
-	g2 := make([]*G1, N)
 	for i := 0; i < testTimes; i++ {
 		for j := 0; j < N; j++ {
 			g1[j] = randomG1(t)
-			g2[j] = &G1{}
-			*g2[j] = *g1[j]
 		}
-		affinize(g2)
+		g2 := affinize(g1)
 		for j := 0; j < N; j++ {
 			g1[j].toAffine()
-			if !g1[j].IsEqual(g2[j]) {
+			if !g1[j].IsEqual(&g2[j]) {
 				t.Fatal("failure to preserve points")
 			}
 			if g2[j].z.IsEqual(&g1[j].z) != 1 {
diff --git a/ecc/bls12381/pair.go b/ecc/bls12381/pair.go
index ead99d03..5cf108f3 100644
--- a/ecc/bls12381/pair.go
+++ b/ecc/bls12381/pair.go
@@ -4,9 +4,10 @@ import "github.com/cloudflare/circl/ecc/bls12381/ff"
 
 // Pair calculates the ate-pairing of P and Q.
 func Pair(P *G1, Q *G2) *Gt {
-	P.toAffine()
+	affP := *P
+	affP.toAffine()
 	mi := &ff.Fp12{}
-	miller(mi, P, Q)
+	miller(mi, &affP, Q)
 	e := &Gt{}
 	finalExp(e, mi)
 	return e
@@ -82,9 +83,9 @@ func ProdPair(P []*G1, Q []*G2, n []*Scalar) *Gt {
 	out := new(ff.Fp12)
 	out.SetOne()
 
-	affinize(P)
-	for i := range P {
-		miller(mi, P[i], Q[i])
+	affineP := affinize(P)
+	for i := range affineP {
+		miller(mi, &affineP[i], Q[i])
 		nb, _ := n[i].MarshalBinary()
 		ei.Exp(mi, nb)
 		out.Mul(out, ei)
@@ -105,13 +106,12 @@ func ProdPairFrac(P []*G1, Q []*G2, signs []int) *Gt {
 	out := new(ff.Fp12)
 	out.SetOne()
 
-	affinize(P)
-	for i := range P {
-		g := *P[i]
+	affineP := affinize(P)
+	for i := range affineP {
 		if signs[i] == -1 {
-			g.Neg()
+			affineP[i].Neg()
 		}
-		miller(mi, &g, Q[i])
+		miller(mi, &affineP[i], Q[i])
 		out.Mul(mi, out)
 	}
 
diff --git a/ecc/bls12381/pair_test.go b/ecc/bls12381/pair_test.go
index 46751d85..14ebe4b3 100644
--- a/ecc/bls12381/pair_test.go
+++ b/ecc/bls12381/pair_test.go
@@ -79,6 +79,52 @@ func TestProdPairFrac(t *testing.T) {
 	}
 }
 
+func TestInputs(t *testing.T) {
+	t.Run("Pair", func(t *testing.T) {
+		P := *randomG1(t)
+		Q := *randomG2(t)
+		oldP := P
+		oldQ := Q
+		_ = Pair(&P, &Q)
+		test.CheckOk(P == oldP, "the point P was overwritten", t)
+		test.CheckOk(Q == oldQ, "the point Q was overwritten", t)
+	})
+
+	t.Run("ProdPair", func(t *testing.T) {
+		P0, P1 := *randomG1(t), *randomG1(t)
+		Q0, Q1 := *randomG2(t), *randomG2(t)
+		n0, n1 := *randomScalar(t), *randomScalar(t)
+
+		oldP0, oldP1 := P0, P1
+		oldQ0, oldQ1 := Q0, Q1
+		oldn0, oldn1 := n0, n1
+
+		_ = ProdPair([]*G1{&P0, &P1}, []*G2{&Q0, &Q1}, []*Scalar{&n0, &n1})
+
+		test.CheckOk(P0 == oldP0, "the point P0 was overwritten", t)
+		test.CheckOk(P1 == oldP1, "the point P1 was overwritten", t)
+		test.CheckOk(Q0 == oldQ0, "the point Q0 was overwritten", t)
+		test.CheckOk(Q1 == oldQ1, "the point Q1 was overwritten", t)
+		test.CheckOk(n0 == oldn0, "the scalar n0 was overwritten", t)
+		test.CheckOk(n1 == oldn1, "the scalar n1 was overwritten", t)
+	})
+
+	t.Run("ProdPairFrac", func(t *testing.T) {
+		P0, P1 := *randomG1(t), *randomG1(t)
+		Q0, Q1 := *randomG2(t), *randomG2(t)
+
+		oldP0, oldP1 := P0, P1
+		oldQ0, oldQ1 := Q0, Q1
+
+		_ = ProdPairFrac([]*G1{&P0, &P1}, []*G2{&Q0, &Q1}, []int{1, -1})
+
+		test.CheckOk(P0 == oldP0, "the point P0 was overwritten", t)
+		test.CheckOk(P1 == oldP1, "the point P1 was overwritten", t)
+		test.CheckOk(Q0 == oldQ0, "the point Q0 was overwritten", t)
+		test.CheckOk(Q1 == oldQ1, "the point Q1 was overwritten", t)
+	})
+}
+
 func TestPairBilinear(t *testing.T) {
 	testTimes := 1 << 5
 	for i := 0; i < testTimes; i++ {