diff --git a/kairos-server/src/lib.rs b/kairos-server/src/lib.rs
index 7efc0001..7bc45aae 100644
--- a/kairos-server/src/lib.rs
+++ b/kairos-server/src/lib.rs
@@ -9,8 +9,8 @@ use state::LockedBatchState;
 
 pub use errors::AppErr;
 
-type PublicKey = String;
-type Signature = String;
+type PublicKey = Vec<u8>;
+type Signature = Vec<u8>;
 
 pub fn app_router(state: LockedBatchState) -> Router {
     Router::new()
diff --git a/kairos-server/src/routes/deposit.rs b/kairos-server/src/routes/deposit.rs
index f40cecd8..b77ccb7f 100644
--- a/kairos-server/src/routes/deposit.rs
+++ b/kairos-server/src/routes/deposit.rs
@@ -42,7 +42,7 @@ pub async fn deposit_handler(
     *balance = updated_balance;
 
     tracing::info!(
-        "Updated account public_key={} balance={}",
+        "Updated account public_key={:?} balance={}",
         public_key,
         updated_balance
     );
diff --git a/kairos-server/src/routes/withdraw.rs b/kairos-server/src/routes/withdraw.rs
index 2fdf0968..3fb72bc5 100644
--- a/kairos-server/src/routes/withdraw.rs
+++ b/kairos-server/src/routes/withdraw.rs
@@ -63,7 +63,7 @@ pub async fn withdraw_handler(
     }
 
     tracing::info!(
-        "Updated account public_key={} balance={}",
+        "Updated account public_key={:?} balance={}",
         withdrawal.public_key,
         updated_balance
     );