Change default `to_bits` and `to_bytes` functions to the safe versions

crypto-primitives/src/nizk/gm17/constraints.rs

@@ -388,13 +388,6 @@ where
         }
         Ok(bytes)
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 #[cfg(test)]

crypto-primitives/src/nizk/groth16/constraints.rs

@@ -335,13 +335,6 @@ where
         }
         Ok(bytes)
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 #[cfg(test)]

crypto-primitives/src/prf/blake2s/constraints.rs

@@ -447,14 +447,6 @@ impl ToBytesGadget for Blake2sOutputGadget
     ) -> Result<Vec<UInt8>, SynthesisError> {
         Ok(self.0.clone())
     }
-
-    #[inline]
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 impl<ConstraintF: PrimeField> AllocGadget<[u8; 32], ConstraintF> for Blake2sOutputGadget {

crypto-primitives/src/signature/schnorr/constraints.rs

@@ -208,12 +208,4 @@ where
     ) -> Result<Vec<UInt8>, SynthesisError> {
         self.pub_key.to_bytes(&mut cs.ns(|| "PubKey To Bytes"))
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        mut cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.pub_key
-            .to_bytes_strict(&mut cs.ns(|| "PubKey To Bytes"))
-    }
 }

r1cs-std/src/bits/boolean.rs

@@ -802,6 +802,7 @@ impl ConditionalEqGadget for Boolean {
 }
 
 impl<ConstraintF: Field> ToBytesGadget<ConstraintF> for Boolean {
+    /// Outputs `1u8` if `self` is true, and `0u8` otherwise.
     fn to_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         _cs: CS,
@@ -813,14 +814,6 @@ impl ToBytesGadget for Boolean {
         let byte = UInt8 { bits, value };
         Ok(vec![byte])
     }
-
-    /// Additionally checks if the produced list of booleans is 'valid'.
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 impl<ConstraintF: PrimeField> CondSelectGadget<ConstraintF> for Boolean {

r1cs-std/src/bits/mod.rs

@@ -11,16 +11,24 @@ pub mod uint64;
 pub mod uint8;
 
 pub trait ToBitsGadget<ConstraintF: Field> {
+    /// Outputs the canonical bit-wise representation of `self`.
+    ///
+    /// This is the correct default for 99% of use cases.
     fn to_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         cs: CS,
     ) -> Result<Vec<Boolean>, SynthesisError>;
 
-    /// Additionally checks if the produced list of booleans is 'valid'.
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
+    /// Outputs a possibly non-unique bit-wise representation of `self`.
+    ///
+    /// If you're not absolutely certain that your usecase can get away with a
+    /// non-canonical representation, please use `self.to_bits(cs)` instead.
+    fn to_non_unique_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         cs: CS,
-    ) -> Result<Vec<Boolean>, SynthesisError>;
+    ) -> Result<Vec<Boolean>, SynthesisError> {
+        self.to_bits(cs)
+    }
 }
 
 impl<ConstraintF: Field> ToBitsGadget<ConstraintF> for Boolean {
@@ -30,13 +38,6 @@ impl ToBitsGadget for Boolean {
     ) -> Result<Vec<Boolean>, SynthesisError> {
         Ok(vec![self.clone()])
     }
-
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        _: CS,
-    ) -> Result<Vec<Boolean>, SynthesisError> {
-        Ok(vec![self.clone()])
-    }
 }
 
 impl<ConstraintF: Field> ToBitsGadget<ConstraintF> for [Boolean] {
@@ -46,14 +47,8 @@ impl ToBitsGadget for [Boolean] {
     ) -> Result<Vec<Boolean>, SynthesisError> {
         Ok(self.to_vec())
     }
-
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        _cs: CS,
-    ) -> Result<Vec<Boolean>, SynthesisError> {
-        Ok(self.to_vec())
-    }
 }
+
 impl<ConstraintF: Field> ToBitsGadget<ConstraintF> for Vec<Boolean> {
     fn to_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
@@ -61,13 +56,6 @@ impl ToBitsGadget for Vec {
     ) -> Result<Vec<Boolean>, SynthesisError> {
         Ok(self.clone())
     }
-
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        _cs: CS,
-    ) -> Result<Vec<Boolean>, SynthesisError> {
-        Ok(self.clone())
-    }
 }
 
 impl<ConstraintF: Field> ToBitsGadget<ConstraintF> for [UInt8] {
@@ -81,26 +69,27 @@ impl ToBitsGadget for [UInt8] {
         }
         Ok(result)
     }
-
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<Boolean>, SynthesisError> {
-        self.to_bits(cs)
-    }
 }
 
 pub trait ToBytesGadget<ConstraintF: Field> {
+    /// Outputs a canonical byte-wise representation of `self`.
+    ///
+    /// This is the correct default for 99% of use cases.
     fn to_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError>;
 
-    /// Additionally checks if the produced list of booleans is 'valid'.
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
+    /// Outputs a possibly non-unique byte decomposition of `self`.
+    ///
+    /// If you're not absolutely certain that your usecase can get away with a
+    /// non-canonical representation, please use `self.to_bytes(cs)` instead.
+    fn to_non_unique_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError>;
+    ) -> Result<Vec<UInt8>, SynthesisError> {
+        self.to_bytes(cs)
+    }
 }
 
 impl<ConstraintF: Field> ToBytesGadget<ConstraintF> for [UInt8] {
@@ -110,13 +99,6 @@ impl ToBytesGadget for [UInt8] {
     ) -> Result<Vec<UInt8>, SynthesisError> {
         Ok(self.to_vec())
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 impl<'a, ConstraintF: Field, T: 'a + ToBytesGadget<ConstraintF>> ToBytesGadget<ConstraintF>
@@ -128,13 +110,6 @@ impl<'a, ConstraintF: Field, T: 'a + ToBytesGadget> ToBytesGadget
     ) -> Result<Vec<UInt8>, SynthesisError> {
         (*self).to_bytes(cs)
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 impl<'a, ConstraintF: Field> ToBytesGadget<ConstraintF> for &'a [UInt8] {
@@ -144,11 +119,4 @@ impl<'a, ConstraintF: Field> ToBytesGadget for &'a [UInt8] {
     ) -> Result<Vec<UInt8>, SynthesisError> {
         Ok(self.to_vec())
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }

r1cs-std/src/bits/uint32.rs

@@ -306,13 +306,6 @@ impl ToBytesGadget for UInt32 {
 
         Ok(bytes)
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 impl PartialEq for UInt32 {

r1cs-std/src/bits/uint64.rs

@@ -310,13 +310,6 @@ impl ToBytesGadget for UInt64 {
 
         Ok(bytes)
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
-        &self,
-        cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
-    }
 }
 
 impl PartialEq for UInt64 {

r1cs-std/src/fields/fp.rs

@@ -326,9 +326,18 @@ impl NEqGadget for FpGadget {
 }
 
 impl<F: PrimeField> ToBitsGadget<F> for FpGadget<F> {
-    /// Outputs the binary representation of the value in `self` in *big-endian*
+    /// Outputs the unique bit-wise decomposition of `self` in *big-endian*
     /// form.
     fn to_bits<CS: ConstraintSystem<F>>(&self, mut cs: CS) -> Result<Vec<Boolean>, SynthesisError> {
+        let bits = self.to_non_unique_bits(&mut cs)?;
+        Boolean::enforce_in_field::<_, _, F>(&mut cs, &bits)?;
+        Ok(bits)
+    }
+
+    fn to_non_unique_bits<CS: ConstraintSystem<F>>(
+        &self,
+        mut cs: CS,
+    ) -> Result<Vec<Boolean>, SynthesisError> {
         let num_bits = F::Params::MODULUS_BITS;
         use algebra::BitIterator;
         let bit_values = match self.value {
@@ -375,20 +384,29 @@ impl ToBitsGadget for FpGadget {
 
         Ok(bits.into_iter().map(Boolean::from).collect())
     }
-
-    fn to_bits_strict<CS: ConstraintSystem<F>>(
-        &self,
-        mut cs: CS,
-    ) -> Result<Vec<Boolean>, SynthesisError> {
-        let bits = self.to_bits(&mut cs)?;
-        Boolean::enforce_in_field::<_, _, F>(&mut cs, &bits)?;
-
-        Ok(bits)
-    }
 }
 
 impl<F: PrimeField> ToBytesGadget<F> for FpGadget<F> {
+    /// Outputs the unique byte decomposition of `self` in *little-endian*
+    /// form.
     fn to_bytes<CS: ConstraintSystem<F>>(&self, mut cs: CS) -> Result<Vec<UInt8>, SynthesisError> {
+        let bytes = self.to_non_unique_bytes(&mut cs)?;
+        Boolean::enforce_in_field::<_, _, F>(
+            &mut cs,
+            &bytes.iter()
+                .flat_map(|byte_gadget| byte_gadget.into_bits_le())
+                // This reverse maps the bits into big-endian form, as required by `enforce_in_field`.
+                .rev()
+                .collect::<Vec<_>>(),
+        )?;
+
+        Ok(bytes)
+    }
+
+    fn to_non_unique_bytes<CS: ConstraintSystem<F>>(
+        &self,
+        mut cs: CS,
+    ) -> Result<Vec<UInt8>, SynthesisError> {
         let byte_values = match self.value {
             Some(value) => to_bytes![&value.into_repr()]?
                 .into_iter()
@@ -425,23 +443,6 @@ impl ToBytesGadget for FpGadget {
 
         Ok(bytes)
     }
-
-    fn to_bytes_strict<CS: ConstraintSystem<F>>(
-        &self,
-        mut cs: CS,
-    ) -> Result<Vec<UInt8>, SynthesisError> {
-        let bytes = self.to_bytes(&mut cs)?;
-        Boolean::enforce_in_field::<_, _, F>(
-            &mut cs,
-            &bytes.iter()
-                .flat_map(|byte_gadget| byte_gadget.into_bits_le())
-                // This reverse maps the bits into big-endian form, as required by `enforce_in_field`.
-                .rev()
-                .collect::<Vec<_>>(),
-        )?;
-
-        Ok(bytes)
-    }
 }
 
 impl<F: PrimeField> CondSelectGadget<F> for FpGadget<F> {

r1cs-std/src/fields/fp12.rs

@@ -731,12 +731,12 @@ where
         Ok(c0)
     }
 
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<Boolean>, SynthesisError> {
-        let mut c0 = self.c0.to_bits_strict(cs.ns(|| "c0"))?;
-        let mut c1 = self.c1.to_bits_strict(cs.ns(|| "c1"))?;
+        let mut c0 = self.c0.to_non_unique_bits(cs.ns(|| "c0"))?;
+        let mut c1 = self.c1.to_non_unique_bits(cs.ns(|| "c1"))?;
         c0.append(&mut c1);
         Ok(c0)
     }
@@ -757,12 +757,12 @@ where
         Ok(c0)
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
-        let mut c0 = self.c0.to_bytes_strict(cs.ns(|| "c0"))?;
-        let mut c1 = self.c1.to_bytes_strict(cs.ns(|| "c1"))?;
+        let mut c0 = self.c0.to_non_unique_bytes(cs.ns(|| "c0"))?;
+        let mut c1 = self.c1.to_non_unique_bytes(cs.ns(|| "c1"))?;
         c0.append(&mut c1);
         Ok(c0)
     }

r1cs-std/src/fields/fp2.rs

@@ -527,12 +527,12 @@ impl, ConstraintF: PrimeField> ToBitsGadget
         Ok(c0)
     }
 
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<Boolean>, SynthesisError> {
-        let mut c0 = self.c0.to_bits_strict(cs.ns(|| "c0"))?;
-        let mut c1 = self.c1.to_bits_strict(cs.ns(|| "c1"))?;
+        let mut c0 = self.c0.to_non_unique_bits(cs.ns(|| "c0"))?;
+        let mut c1 = self.c1.to_non_unique_bits(cs.ns(|| "c1"))?;
         c0.append(&mut c1);
         Ok(c0)
     }
@@ -551,12 +551,12 @@ impl, ConstraintF: PrimeField> ToBytesGadget<
         Ok(c0)
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
-        let mut c0 = self.c0.to_bytes_strict(cs.ns(|| "c0"))?;
-        let mut c1 = self.c1.to_bytes_strict(cs.ns(|| "c1"))?;
+        let mut c0 = self.c0.to_non_unique_bytes(cs.ns(|| "c0"))?;
+        let mut c1 = self.c1.to_non_unique_bytes(cs.ns(|| "c1"))?;
         c0.append(&mut c1);
         Ok(c0)
     }

r1cs-std/src/fields/fp6_3over2.rs

@@ -800,13 +800,13 @@ where
         Ok(c0)
     }
 
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<Boolean>, SynthesisError> {
-        let mut c0 = self.c0.to_bits_strict(cs.ns(|| "c0"))?;
-        let mut c1 = self.c1.to_bits_strict(cs.ns(|| "c1"))?;
-        let mut c2 = self.c2.to_bits_strict(cs.ns(|| "c2"))?;
+        let mut c0 = self.c0.to_non_unique_bits(cs.ns(|| "c0"))?;
+        let mut c1 = self.c1.to_non_unique_bits(cs.ns(|| "c1"))?;
+        let mut c2 = self.c2.to_non_unique_bits(cs.ns(|| "c2"))?;
 
         c0.append(&mut c1);
         c0.append(&mut c2);
@@ -834,11 +834,18 @@ where
         Ok(c0)
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
-        cs: CS,
+        mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
+        let mut c0 = self.c0.to_non_unique_bytes(cs.ns(|| "c0"))?;
+        let mut c1 = self.c1.to_non_unique_bytes(cs.ns(|| "c1"))?;
+        let mut c2 = self.c2.to_non_unique_bytes(cs.ns(|| "c2"))?;
+
+        c0.append(&mut c1);
+        c0.append(&mut c2);
+
+        Ok(c0)
     }
 }
 

r1cs-std/src/fields/mod.rs

@@ -452,7 +452,9 @@ pub(crate) mod tests {
 
         let n = F::alloc(&mut cs.ns(|| "alloc new var"), || Ok(negone)).unwrap();
         let _ = n.to_bytes(&mut cs.ns(|| "ToBytes")).unwrap();
-        let _ = n.to_bytes_strict(&mut cs.ns(|| "ToBytes Strict")).unwrap();
+        let _ = n
+            .to_non_unique_bytes(&mut cs.ns(|| "ToBytes Strict"))
+            .unwrap();
 
         let ab_false = a
             .conditionally_add_constant(

r1cs-std/src/groups/curves/short_weierstrass/bls12/mod.rs

@@ -52,11 +52,12 @@ impl ToBytesGadget for G1PreparedGadget
         self.0.to_bytes(&mut cs.ns(|| "g_alpha to bytes"))
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<P::Fp>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<P::Fp>>(
         &self,
-        cs: CS,
+        mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
+        self.0
+            .to_non_unique_bytes(&mut cs.ns(|| "g_alpha to bytes"))
     }
 }
 
@@ -86,11 +87,17 @@ impl ToBytesGadget for G2PreparedGadget
         Ok(bytes)
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<P::Fp>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<P::Fp>>(
         &self,
-        cs: CS,
+        mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
-        self.to_bytes(cs)
+        let mut bytes = Vec::new();
+        for (i, coeffs) in self.ell_coeffs.iter().enumerate() {
+            let mut cs = cs.ns(|| format!("Iteration {}", i));
+            bytes.extend_from_slice(&coeffs.0.to_non_unique_bytes(&mut cs.ns(|| "c0"))?);
+            bytes.extend_from_slice(&coeffs.1.to_non_unique_bytes(&mut cs.ns(|| "c1"))?);
+        }
+        Ok(bytes)
     }
 }
 

r1cs-std/src/groups/curves/short_weierstrass/mod.rs

@@ -605,16 +605,16 @@ where
         Ok(x_bits)
     }
 
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<Boolean>, SynthesisError> {
         let mut x_bits = self
             .x
-            .to_bits_strict(&mut cs.ns(|| "X Coordinate To Bits"))?;
+            .to_non_unique_bits(&mut cs.ns(|| "X Coordinate To Bits"))?;
         let y_bits = self
             .y
-            .to_bits_strict(&mut cs.ns(|| "Y Coordinate To Bits"))?;
+            .to_non_unique_bits(&mut cs.ns(|| "Y Coordinate To Bits"))?;
         x_bits.extend_from_slice(&y_bits);
         x_bits.push(self.infinity);
 
@@ -640,17 +640,19 @@ where
         Ok(x_bytes)
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
         let mut x_bytes = self
             .x
-            .to_bytes_strict(&mut cs.ns(|| "X Coordinate To Bytes"))?;
+            .to_non_unique_bytes(&mut cs.ns(|| "X Coordinate To Bytes"))?;
         let y_bytes = self
             .y
-            .to_bytes_strict(&mut cs.ns(|| "Y Coordinate To Bytes"))?;
-        let inf_bytes = self.infinity.to_bytes(&mut cs.ns(|| "Infinity to Bytes"))?;
+            .to_non_unique_bytes(&mut cs.ns(|| "Y Coordinate To Bytes"))?;
+        let inf_bytes = self
+            .infinity
+            .to_non_unique_bytes(&mut cs.ns(|| "Infinity to Bytes"))?;
         x_bytes.extend_from_slice(&y_bytes);
         x_bytes.extend_from_slice(&inf_bytes);
 

r1cs-std/src/groups/curves/twisted_edwards/mod.rs

@@ -1359,12 +1359,16 @@ where
         Ok(x_bits)
     }
 
-    fn to_bits_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bits<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<Boolean>, SynthesisError> {
-        let mut x_bits = self.x.to_bits_strict(cs.ns(|| "X Coordinate To Bits"))?;
-        let y_bits = self.y.to_bits_strict(cs.ns(|| "Y Coordinate To Bits"))?;
+        let mut x_bits = self
+            .x
+            .to_non_unique_bits(cs.ns(|| "X Coordinate To Bits"))?;
+        let y_bits = self
+            .y
+            .to_non_unique_bits(cs.ns(|| "Y Coordinate To Bits"))?;
         x_bits.extend_from_slice(&y_bits);
 
         Ok(x_bits)
@@ -1387,12 +1391,12 @@ where
         Ok(x_bytes)
     }
 
-    fn to_bytes_strict<CS: ConstraintSystem<ConstraintF>>(
+    fn to_non_unique_bytes<CS: ConstraintSystem<ConstraintF>>(
         &self,
         mut cs: CS,
     ) -> Result<Vec<UInt8>, SynthesisError> {
-        let mut x_bytes = self.x.to_bytes_strict(cs.ns(|| "x"))?;
-        let y_bytes = self.y.to_bytes_strict(cs.ns(|| "y"))?;
+        let mut x_bytes = self.x.to_non_unique_bytes(cs.ns(|| "x"))?;
+        let y_bytes = self.y.to_non_unique_bytes(cs.ns(|| "y"))?;
         x_bytes.extend_from_slice(&y_bytes);
 
         Ok(x_bytes)

r1cs-std/src/groups/mod.rs

@@ -206,11 +206,13 @@ mod test {
         assert_eq!(b2, b_b);
 
         let _ = a.to_bytes(&mut cs.ns(|| "ToBytes")).unwrap();
-        let _ = a.to_bytes_strict(&mut cs.ns(|| "ToBytes Strict")).unwrap();
+        let _ = a
+            .to_non_unique_bytes(&mut cs.ns(|| "ToBytes Strict"))
+            .unwrap();
 
         let _ = b.to_bytes(&mut cs.ns(|| "b ToBytes")).unwrap();
         let _ = b
-            .to_bytes_strict(&mut cs.ns(|| "b ToBytes Strict"))
+            .to_non_unique_bytes(&mut cs.ns(|| "b ToBytes Strict"))
             .unwrap();
         if !cs.is_satisfied() {
             println!("{:?}", cs.which_is_unsatisfied().unwrap());