Align Ristretto255::random_scalar() with spec (#142)

daxpedda · web-flow · commit f3f4fef0e92b · 2025-05-07T15:40:24.000-07:00
diff --git a/src/group/ristretto.rs b/src/group/ristretto.rs
@@ -96,9 +96,10 @@ impl Group for Ristretto255 {
 
     fn random_scalar<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar {
         loop {
-            let scalar = Scalar::random(rng);
+            let mut scalar_bytes = [0u8; 32];
+            rng.fill_bytes(&mut scalar_bytes);
 
-            if scalar != Scalar::ZERO {
+            if let Ok(scalar) = Self::deserialize_scalar(&scalar_bytes) {
                 break scalar;
             }
         }

Original file line number	Diff line number	Diff line change
`@@ -96,9 +96,10 @@ impl Group for Ristretto255 {`
`96`	`96`
`97`	`97`	`fn random_scalar<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar {`
`98`	`98`	`loop {`
`99`		`- let scalar = Scalar::random(rng);`
	`99`	`+ let mut scalar_bytes = [0u8; 32];`
	`100`	`+ rng.fill_bytes(&mut scalar_bytes);`
`100`	`101`
`101`		`- if scalar != Scalar::ZERO {`
	`102`	`+ if let Ok(scalar) = Self::deserialize_scalar(&scalar_bytes) {`
`102`	`103`	`break scalar;`
`103`	`104`	`}`
`104`	`105`	`}`