Tracking PR for v0.9.0 release (#278)

* chore: update crate version to v0.9.0
* chore: remove deprecated re-exports
* chore: remove Box re-export
* feat: implement pure-Rust keygen and signing for RpoFalcon512 (#285)
* feat: add reproducible builds (#296)
* fix: address a few issues for migrating Miden VM  (#298)
* feat: add RngCore supertrait for FeltRng (#299)

---------

Co-authored-by: Al-Kindi-0 <82364884+Al-Kindi-0@users.noreply.github.com>
Co-authored-by: Paul-Henry Kajfasz <42912740+phklive@users.noreply.github.com>

src/rand/mod.rs

@@ -1,5 +1,6 @@
 //! Pseudo-random element generation.
 
+use rand::RngCore;
 pub use winter_crypto::{DefaultRandomCoin as WinterRandomCoin, RandomCoin, RandomCoinError};
 pub use winter_utils::Randomizable;
 
@@ -11,7 +12,7 @@ pub use rpo::RpoRandomCoin;
 /// Pseudo-random element generator.
 ///
 /// An instance can be used to draw, uniformly at random, base field elements as well as [Word]s.
-pub trait FeltRng {
+pub trait FeltRng: RngCore {
     /// Draw, uniformly at random, a base field element.
     fn draw_element(&mut self) -> Felt;
 

src/rand/rpo.rs

@@ -1,9 +1,10 @@
-use super::{Felt, FeltRng, FieldElement, RandomCoin, RandomCoinError, Word, ZERO};
+use super::{Felt, FeltRng, FieldElement, RandomCoin, RandomCoinError, RngCore, Word, ZERO};
 use crate::{
     hash::rpo::{Rpo256, RpoDigest},
     utils::{ByteReader, ByteWriter, Deserializable, DeserializationError, Serializable},
 };
 use alloc::{string::ToString, vec::Vec};
+use rand_core::impls;
 
 // CONSTANTS
 // ================================================================================================
@@ -20,9 +21,9 @@ const HALF_RATE_WIDTH: usize = (Rpo256::RATE_RANGE.end - Rpo256::RATE_RANGE.star
 ///
 /// The simplification is related to the following facts:
 /// 1. A call to the reseed method implies one and only one call to the permutation function.
-///  This is possible because in our case we never reseed with more than 4 field elements.
+///    This is possible because in our case we never reseed with more than 4 field elements.
 /// 2. As a result of the previous point, we don't make use of an input buffer to accumulate seed
-///  material.
+///    material.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct RpoRandomCoin {
     state: [Felt; STATE_WIDTH],
@@ -61,6 +62,11 @@ impl RpoRandomCoin {
         (self.state, self.current)
     }
 
+    /// Fills `dest` with random data.
+    pub fn fill_bytes(&mut self, dest: &mut [u8]) {
+        <Self as RngCore>::fill_bytes(self, dest)
+    }
+
     fn draw_basefield(&mut self) -> Felt {
         if self.current == RATE_END {
             Rpo256::apply_permutation(&mut self.state);
@@ -183,6 +189,28 @@ impl FeltRng for RpoRandomCoin {
     }
 }
 
+// RNGCORE IMPLEMENTATION
+// ------------------------------------------------------------------------------------------------
+
+impl RngCore for RpoRandomCoin {
+    fn next_u32(&mut self) -> u32 {
+        self.draw_basefield().as_int() as u32
+    }
+
+    fn next_u64(&mut self) -> u64 {
+        impls::next_u64_via_u32(self)
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        impls::fill_bytes_via_next(self, dest)
+    }
+
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand::Error> {
+        self.fill_bytes(dest);
+        Ok(())
+    }
+}
+
 // SERIALIZATION
 // ------------------------------------------------------------------------------------------------