diff --git a/src/ed25519.rs b/src/ed25519.rs
index 033b6be..4bbcbd4 100644
--- a/src/ed25519.rs
+++ b/src/ed25519.rs
@@ -72,7 +72,7 @@ pub fn ed25519_keygen() -> (Ed25519PrivKey, Ed25519PubKey) {
     (sk, pk)
 }
 
-pub fn ed25519_sign(sk: Ed25519PrivKey, msg: SharedPtr) -> Ed25519Signature {
+pub fn ed25519_sign(sk: &Ed25519PrivKey, msg: &SharedPtr) -> Ed25519Signature {
     let sig = Ed25519Signature(SharedPtr::new(64).unwrap());
 
     let mut agent = ED25519AGENT.lock().unwrap();