diff --git a/bls/bignum_pure.go b/bls/bignum_pure.go
index 5b36554..75a397a 100644
--- a/bls/bignum_pure.go
+++ b/bls/bignum_pure.go
@@ -6,6 +6,7 @@ package bls
 import (
 	"crypto/rand"
 	"math/big"
+        "errors"
 )
 
 var _modulus big.Int
@@ -107,8 +108,12 @@ func PowModFr(dst *Fr, a, b *Fr) {
 	(*big.Int)(dst).Exp((*big.Int)(a), (*big.Int)(b), &_modulus)
 }
 
-func InvModFr(dst *Fr, v *Fr) {
+func InvModFr(dst *Fr, v *Fr) error {
+	if EqualZero(v) {
+		return errors.New("division by zero")
+	}
 	(*big.Int)(dst).ModInverse((*big.Int)(v), &_modulus)
+	return nil
 }
 
 // BatchInvModFr computes the inverse for each input.