goas: don't expose nullifier nonce/commitment bytes

goas/atomic_asset_transfer/executor/src/lib.rs

@@ -232,7 +232,7 @@ mod tests {
 
         let bind = OutputWitness::public(
             NoteWitness::basic(32, *common::ZONE_CL_FUNDS_UNIT),
-            cl::NullifierNonce([0u8; 32]),
+            cl::NullifierNonce::random(&mut rng),
         );
 
         let mut alice = common::new_account(&mut rng);

goas/cl/cl/src/nullifier.rs

@@ -25,13 +25,13 @@ pub struct NullifierSecret(pub [u8; 16]);
 // can be provided to anyone wishing to transfer
 // you a note
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-pub struct NullifierCommitment(pub [u8; 32]);
+pub struct NullifierCommitment([u8; 32]);
 
 // To allow users to maintain fewer nullifier secrets, we
 // provide a nonce to differentiate notes controlled by the same
 // secret. Each note is assigned a unique nullifier nonce.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-pub struct NullifierNonce(pub [u8; 32]);
+pub struct NullifierNonce([u8; 32]);
 
 // The nullifier attached to input notes to prove an input has not
 // already been spent.