Remove uses of ThreadRng

ThreadRng shouldn't be used directly as it restricts the kinds of random
number generators that people can pass as an input

ironfish-rust/src/frost_utils/signing_commitment.rs

@@ -76,7 +76,7 @@ mod test {
     use crate::test_util::create_identifiers;
     use ff::Field;
     use jubjub::Fr;
-    use rand::rngs::ThreadRng;
+    use rand::thread_rng;
 
     #[test]
     pub fn test_seed_provides_same_result() {
@@ -85,14 +85,13 @@ mod test {
 
         let identifiers = create_identifiers(10);
 
-        let mut rng = ThreadRng::default();
         let key_packages = split_secret(
             &SecretShareConfig {
                 identifiers,
                 min_signers: 2,
                 secret: key.to_bytes().to_vec(),
             },
-            &mut rng,
+            thread_rng(),
         )
         .expect("key shares to be created");
         let key_package = key_packages

ironfish-rust/src/frost_utils/split_secret.rs

@@ -7,7 +7,7 @@ use ironfish_frost::frost::{
     keys::{IdentifierList, KeyPackage, PublicKeyPackage},
     Identifier, SigningKey,
 };
-use rand::rngs::ThreadRng;
+use rand::{CryptoRng, RngCore};
 use std::collections::HashMap;
 
 use crate::errors::{IronfishError, IronfishErrorKind};
@@ -18,9 +18,9 @@ pub struct SecretShareConfig {
     pub secret: Vec<u8>,
 }
 
-pub(crate) fn split_secret(
+pub(crate) fn split_secret<R: RngCore + CryptoRng>(
     config: &SecretShareConfig,
-    rng: &mut ThreadRng,
+    mut rng: R,
 ) -> Result<(HashMap<Identifier, KeyPackage>, PublicKeyPackage), IronfishError> {
     let secret_bytes: [u8; 32] = config
         .secret
@@ -37,7 +37,7 @@ pub(crate) fn split_secret(
         config.identifiers.len() as u16,
         config.min_signers,
         identifier_list,
-        rng,
+        &mut rng,
     )?;
 
     for (_k, v) in shares.clone() {
@@ -71,8 +71,8 @@ mod test {
             secret: vec,
         };
 
-        let mut rng = rand::thread_rng();
-        let result = split_secret(&config, &mut rng);
+        let rng = rand::thread_rng();
+        let result = split_secret(&config, rng);
         assert!(result.is_err());
         assert!(
             matches!(result.unwrap_err().kind, IronfishErrorKind::InvalidSecret),
@@ -85,7 +85,7 @@ mod test {
         let identifiers = create_identifiers(10);
         let identifiers_length = identifiers.len();
 
-        let mut rng = rand::thread_rng();
+        let rng = rand::thread_rng();
 
         let key = SaplingKey::generate_key().spend_authorizing_key.to_bytes();
 
@@ -95,7 +95,7 @@ mod test {
             secret: key.to_vec(),
         };
 
-        let (key_packages, _) = split_secret(&config, &mut rng).unwrap();
+        let (key_packages, _) = split_secret(&config, rng).unwrap();
         assert_eq!(key_packages.len(), identifiers_length);
 
         let key_parts: Vec<_> = key_packages.values().cloned().collect();

ironfish-rust/src/frost_utils/split_spender_key.rs

@@ -48,9 +48,9 @@ pub fn split_spender_key(
         secret,
     };
 
-    let mut rng: rand::prelude::ThreadRng = thread_rng();
+    let rng = thread_rng();
 
-    let (key_packages, public_key_package) = split_secret(&secret_config, &mut rng)?;
+    let (key_packages, public_key_package) = split_secret(&secret_config, rng)?;
 
     let authorizing_key_bytes = public_key_package.verifying_key().serialize();