diff --git a/src/groth16/generator.rs b/src/groth16/generator.rs
index 084e7a3..d04ed6c 100644
--- a/src/groth16/generator.rs
+++ b/src/groth16/generator.rs
@@ -3,7 +3,7 @@ use std::ops::{AddAssign, MulAssign};
 use std::sync::Arc;
 
 use ff::{Field, PrimeField};
-use group::{cofactor::CofactorCurveAffine, Curve, Group, Wnaf};
+use group::{cofactor::CofactorCurveAffine, Curve, Group, Wnaf, WnafGroup};
 use pairing::Engine;
 
 use super::{Parameters, VerifyingKey};
@@ -22,6 +22,8 @@ pub fn generate_random_parameters<E, C, R>(
 ) -> Result<Parameters<E>, SynthesisError>
 where
     E: Engine,
+    E::G1: WnafGroup,
+    E::G2: WnafGroup,
     C: Circuit<E::Fr>,
     R: RngCore,
 {
@@ -165,6 +167,8 @@ pub fn generate_parameters<E, C>(
 ) -> Result<Parameters<E>, SynthesisError>
 where
     E: Engine,
+    E::G1: WnafGroup,
+    E::G2: WnafGroup,
     C: Circuit<E::Fr>,
 {
     let mut assembly = KeypairAssembly {
diff --git a/src/groth16/tests/dummy_engine.rs b/src/groth16/tests/dummy_engine.rs
index 17e0043..8f11fe1 100644
--- a/src/groth16/tests/dummy_engine.rs
+++ b/src/groth16/tests/dummy_engine.rs
@@ -2,7 +2,7 @@ use ff::{Field, PrimeField};
 use group::{
     cofactor::{CofactorCurve, CofactorCurveAffine, CofactorGroup},
     prime::PrimeGroup,
-    Curve, Group, GroupEncoding, UncompressedEncoding,
+    Curve, Group, GroupEncoding, UncompressedEncoding, WnafGroup,
 };
 use pairing::{Engine, MillerLoopResult, MultiMillerLoop, PairingCurveAffine};
 
@@ -414,7 +414,9 @@ impl Curve for Fr {
     fn to_affine(&self) -> Fr {
         *self
     }
+}
 
+impl WnafGroup for Fr {
     fn recommended_wnaf_for_scalar(_: &Self::Scalar) -> usize {
         3
     }