Migrate bellman to rand 0.5

bellman/src/groth16/generator.rs

@@ -1,4 +1,4 @@
-use rand::Rng;
+use rand_core::RngCore;
 
 use std::sync::Arc;
 
@@ -35,15 +35,15 @@ pub fn generate_random_parameters<E, C, R>(
     circuit: C,
     rng: &mut R
 ) -> Result<Parameters<E>, SynthesisError>
-    where E: Engine, C: Circuit<E>, R: Rng
+    where E: Engine, C: Circuit<E>, R: RngCore
 {
-    let g1 = rng.gen();
-    let g2 = rng.gen();
-    let alpha = rng.gen();
-    let beta = rng.gen();
-    let gamma = rng.gen();
-    let delta = rng.gen();
-    let tau = rng.gen();
+    let g1 = E::G1::random(rng);
+    let g2 = E::G2::random(rng);
+    let alpha = E::Fr::random(rng);
+    let beta = E::Fr::random(rng);
+    let gamma = E::Fr::random(rng);
+    let delta = E::Fr::random(rng);
+    let tau = E::Fr::random(rng);
 
     generate_parameters::<E, C>(
         circuit,

bellman/src/groth16/mod.rs

@@ -487,7 +487,7 @@ mod test_with_bls12_381 {
     use {Circuit, SynthesisError, ConstraintSystem};
 
     use ff::Field;
-    use rand::{Rand, thread_rng};
+    use rand::{thread_rng};
     use pairing::bls12_381::{Bls12, Fr};
 
     #[test]
@@ -547,8 +547,8 @@ mod test_with_bls12_381 {
         let pvk = prepare_verifying_key::<Bls12>(&params.vk);
 
         for _ in 0..100 {
-            let a = Fr::rand(rng);
-            let b = Fr::rand(rng);
+            let a = Fr::random(rng);
+            let b = Fr::random(rng);
             let mut c = a;
             c.mul_assign(&b);
 

bellman/src/groth16/prover.rs

@@ -1,4 +1,4 @@
-use rand::Rng;
+use rand_core::RngCore;
 
 use std::sync::Arc;
 
@@ -189,10 +189,10 @@ pub fn create_random_proof<E, C, R, P: ParameterSource<E>>(
     params: P,
     rng: &mut R
 ) -> Result<Proof<E>, SynthesisError>
-    where E: Engine, C: Circuit<E>, R: Rng
+    where E: Engine, C: Circuit<E>, R: RngCore
 {
-    let r = rng.gen();
-    let s = rng.gen();
+    let r = E::Fr::random(rng);
+    let s = E::Fr::random(rng);
 
     create_proof::<E, C, P>(circuit, params, r, s)
 }

bellman/src/groth16/tests/dummy_engine.rs

@@ -6,7 +6,7 @@ use pairing::{Engine, PairingCurveAffine};
 
 use std::cmp::Ordering;
 use std::fmt;
-use rand::{Rand, Rng};
+use rand_core::RngCore;
 use std::num::Wrapping;
 
 const MODULUS_R: Wrapping<u32> = Wrapping(64513);
@@ -20,13 +20,11 @@ impl fmt::Display for Fr {
     }
 }
 
-impl Rand for Fr {
-    fn rand<R: Rng>(rng: &mut R) -> Self {
-        Fr(Wrapping(rng.gen()) % MODULUS_R)
-    }
-}
-
 impl Field for Fr {
+    fn random<R: RngCore>(rng: &mut R) -> Self {
+        Fr(Wrapping(rng.next_u32()) % MODULUS_R)
+    }
+
     fn zero() -> Self {
         Fr(Wrapping(0))
     }
@@ -145,12 +143,6 @@ impl PartialOrd for FrRepr {
     }
 }
 
-impl Rand for FrRepr {
-    fn rand<R: Rng>(rng: &mut R) -> Self {
-        FrRepr([rng.gen()])
-    }
-}
-
 impl fmt::Display for FrRepr {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         write!(f, "{}", (self.0)[0])
@@ -300,6 +292,10 @@ impl CurveProjective for Fr {
     type Scalar = Fr;
     type Engine = DummyEngine;
 
+    fn random<R: RngCore>(rng: &mut R) -> Self {
+        <Fr as Field>::random(rng)
+    }
+
     fn zero() -> Self {
         <Fr as Field>::zero()
     }