refactor: make TransactionAuthenticator return Arc for public key (#2304)

Author: bobbinth

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 ## 0.14.0 (TBD)
 
+### Features
+
+### Changes
+
+- [BREAKING] refactored `TransactionAuthenticator::get_public_key()` method to return `Arc<PublicKey> `instead of `&PublicKey` ([#2304](https://github.com/0xMiden/miden-base/pull/2304)).
+
 ## 0.13.0 (2026-01-16)
 
 ### Features

crates/miden-testing/src/mock_chain/chain.rs

@@ -1094,7 +1094,12 @@ impl Serializable for AccountAuthenticator {
     fn write_into<W: ByteWriter>(&self, target: &mut W) {
         self.authenticator
             .as_ref()
-            .map(|auth| auth.keys().values().collect::<Vec<_>>())
+            .map(|auth| {
+                auth.keys()
+                    .values()
+                    .map(|(secret_key, public_key)| (secret_key, public_key.as_ref().clone()))
+                    .collect::<Vec<_>>()
+            })
             .write_into(target);
     }
 }

crates/miden-tx/src/auth/tx_authenticator.rs

@@ -1,6 +1,7 @@
 use alloc::boxed::Box;
 use alloc::collections::BTreeMap;
 use alloc::string::ToString;
+use alloc::sync::Arc;
 use alloc::vec::Vec;
 
 use miden_processor::FutureMaybeSend;
@@ -145,7 +146,7 @@ pub trait TransactionAuthenticator {
     fn get_public_key(
         &self,
         pub_key_commitment: PublicKeyCommitment,
-    ) -> impl FutureMaybeSend<Option<&PublicKey>>;
+    ) -> impl FutureMaybeSend<Option<Arc<PublicKey>>>;
 }
 
 /// A placeholder type for the generic trait bound of `TransactionAuthenticator<'_,'_,_,T>`
@@ -171,7 +172,7 @@ impl TransactionAuthenticator for UnreachableAuth {
     fn get_public_key(
         &self,
         _pub_key_commitment: PublicKeyCommitment,
-    ) -> impl FutureMaybeSend<Option<&PublicKey>> {
+    ) -> impl FutureMaybeSend<Option<Arc<PublicKey>>> {
         async { unreachable!("Type `UnreachableAuth` must not be instantiated") }
     }
 }
@@ -183,15 +184,15 @@ impl TransactionAuthenticator for UnreachableAuth {
 #[derive(Clone, Debug)]
 pub struct BasicAuthenticator {
     /// pub_key |-> (secret_key, public_key) mapping
-    keys: BTreeMap<PublicKeyCommitment, (AuthSecretKey, PublicKey)>,
+    keys: BTreeMap<PublicKeyCommitment, (AuthSecretKey, Arc<PublicKey>)>,
 }
 
 impl BasicAuthenticator {
     pub fn new(keys: &[AuthSecretKey]) -> Self {
         let mut key_map = BTreeMap::new();
         for secret_key in keys {
             let pub_key = secret_key.public_key();
-            key_map.insert(pub_key.to_commitment(), (secret_key.clone(), pub_key));
+            key_map.insert(pub_key.to_commitment(), (secret_key.clone(), pub_key.into()));
         }
 
         BasicAuthenticator { keys: key_map }
@@ -200,7 +201,10 @@ impl BasicAuthenticator {
     pub fn from_key_pairs(keys: &[(AuthSecretKey, PublicKey)]) -> Self {
         let mut key_map = BTreeMap::new();
         for (secret_key, public_key) in keys {
-            key_map.insert(public_key.to_commitment(), (secret_key.clone(), public_key.clone()));
+            key_map.insert(
+                public_key.to_commitment(),
+                (secret_key.clone(), public_key.clone().into()),
+            );
         }
 
         BasicAuthenticator { keys: key_map }
@@ -210,7 +214,7 @@ impl BasicAuthenticator {
     ///
     /// Map keys represent the public key commitments, and values represent the (secret_key,
     /// public_key) pair that the authenticator would use to sign messages.
-    pub fn keys(&self) -> &BTreeMap<PublicKeyCommitment, (AuthSecretKey, PublicKey)> {
+    pub fn keys(&self) -> &BTreeMap<PublicKeyCommitment, (AuthSecretKey, Arc<PublicKey>)> {
         &self.keys
     }
 }
@@ -244,12 +248,12 @@ impl TransactionAuthenticator for BasicAuthenticator {
     fn get_public_key(
         &self,
         pub_key_commitment: PublicKeyCommitment,
-    ) -> impl FutureMaybeSend<Option<&PublicKey>> {
-        async move { self.keys.get(&pub_key_commitment).map(|(_, pub_key)| pub_key) }
+    ) -> impl FutureMaybeSend<Option<Arc<PublicKey>>> {
+        async move { self.keys.get(&pub_key_commitment).map(|(_, pub_key)| pub_key.clone()) }
     }
 }
 
-// HELPER FUNCTIONS
+// EMPTY AUTHENTICATOR
 // ================================================================================================
 
 impl TransactionAuthenticator for () {
@@ -269,11 +273,14 @@ impl TransactionAuthenticator for () {
     fn get_public_key(
         &self,
         _pub_key_commitment: PublicKeyCommitment,
-    ) -> impl FutureMaybeSend<Option<&PublicKey>> {
+    ) -> impl FutureMaybeSend<Option<Arc<PublicKey>>> {
         async { None }
     }
 }
 
+// TESTS
+// ================================================================================================
+
 #[cfg(test)]
 mod test {
     use miden_protocol::account::auth::AuthSecretKey;