diff --git a/crypto/secp256k1/curve.go b/crypto/secp256k1/curve.go
index 5409ee1d2cdbea22b57c670c8d66bacb07e36c22..8f83cccad9d139e1e044313f0fbeb67a5e6b915a 100644
--- a/crypto/secp256k1/curve.go
+++ b/crypto/secp256k1/curve.go
@@ -116,6 +116,10 @@ func (BitCurve *BitCurve) IsOnCurve(x, y *big.Int) bool {
 // affineFromJacobian reverses the Jacobian transform. See the comment at the
 // top of the file.
 func (BitCurve *BitCurve) affineFromJacobian(x, y, z *big.Int) (xOut, yOut *big.Int) {
+	if z.Sign() == 0 {
+		return new(big.Int), new(big.Int)
+	}
+
 	zinv := new(big.Int).ModInverse(z, BitCurve.P)
 	zinvsq := new(big.Int).Mul(zinv, zinv)