feat: Use rand_xoshiro in account id builder

objects/Cargo.toml

@@ -23,14 +23,15 @@ bench = false
 concurrent = ["std"]
 default = ["std"]
 std = ["assembly/std", "miden-crypto/std", "miden-verifier/std", "vm-core/std", "vm-processor/std"]
-testing = ["dep:winter-rand-utils", "dep:rand"]
+testing = ["dep:winter-rand-utils", "dep:rand", "dep:rand_xoshiro"]
 
 [dependencies]
 assembly = { workspace = true }
 log = { version = "0.4", optional = true }
 miden-crypto = { workspace = true }
 miden-verifier = { workspace = true }
-rand = { workspace = true, optional = true, features = ["small_rng"] }
+rand = { workspace = true, optional = true }
+rand_xoshiro = { version = "0.6.0", default-features = false, optional = true }
 thiserror = { workspace = true }
 vm-core = { workspace = true }
 vm-processor = { workspace = true }

objects/src/accounts/account_id.rs

@@ -50,13 +50,12 @@ impl AccountType {
 impl rand::distributions::Distribution<AccountType> for rand::distributions::Standard {
     /// Samples a uniformly random [`AccountType`] from the given `rng`.
     fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> AccountType {
-        let account_type_distribution = rand::distributions::Uniform::new_inclusive(0, 3);
-        match account_type_distribution.sample(rng) {
+        match rng.gen_range(0..4) {
             0 => AccountType::RegularAccountImmutableCode,
             1 => AccountType::RegularAccountUpdatableCode,
             2 => AccountType::FungibleFaucet,
             3 => AccountType::NonFungibleFaucet,
-            _ => unreachable!("the uniform distribution should not produce higher values"),
+            _ => unreachable!("gen_range should not produce higher values"),
         }
     }
 }
@@ -115,11 +114,10 @@ impl FromStr for AccountStorageMode {
 impl rand::distributions::Distribution<AccountStorageMode> for rand::distributions::Standard {
     /// Samples a uniformly random [`AccountStorageMode`] from the given `rng`.
     fn sample<R: rand::Rng + ?Sized>(&self, rng: &mut R) -> AccountStorageMode {
-        let account_type_distribution = rand::distributions::Uniform::new_inclusive(0, 1);
-        match account_type_distribution.sample(rng) {
+        match rng.gen_range(0..2) {
             0 => AccountStorageMode::Public,
             1 => AccountStorageMode::Private,
-            _ => unreachable!("the uniform distribution should not produce higher values"),
+            _ => unreachable!("gen_range should not produce higher values"),
         }
     }
 }

objects/src/testing/account_id.rs

@@ -188,17 +188,25 @@ impl AccountIdBuilder {
         AccountId::dummy(rng.gen(), account_type, storage_mode)
     }
 
-    /// Builds an [`AccountId`] using the provided seed as input for a [`rand::rngs::StdRng`].
+    /// Builds an [`AccountId`] using the provided seed as input for an RNG implemented in
+    /// [`rand_xoshiro`].
     ///
     /// If no [`AccountType`] or [`AccountStorageMode`] were previously set, random ones are
     /// generated.
     pub fn build_with_seed(self, rng_seed: [u8; 32]) -> AccountId {
-        // On non-64 bit architectures, SmallRng expects 16 bytes as seed input.
+        // Match the implementation of rand::rngs::SmallRng and use different RNGs depending on the
+        // platform.
         #[cfg(not(target_pointer_width = "64"))]
-        let rng_seed: [u8; 16] = rng_seed.as_slice()[0..16]
-            .try_into()
-            .expect("we should have sliced off 16 elements");
-        let mut rng = rand::rngs::SmallRng::from_seed(rng_seed);
+        let mut rng = {
+            let rng_seed: [u8; 16] = rng_seed.as_slice()[0..16]
+                .try_into()
+                .expect("we should have sliced off 16 elements");
+            rand_xoshiro::Xoshiro128PlusPlus::from_seed(rng_seed)
+        };
+
+        #[cfg(target_pointer_width = "64")]
+        let mut rng = rand_xoshiro::Xoshiro256PlusPlus::from_seed(rng_seed);
+
         self.build_with_rng(&mut rng)
     }
 }