diff --git a/src/api.rs b/src/api.rs
index 7ae5ce0..1700656 100644
--- a/src/api.rs
+++ b/src/api.rs
@@ -1008,7 +1008,11 @@ pub fn update_process_state(init_commitment: String, state_id: String, hash2valu
             return Err(ApiError::new("State already existing".to_owned()));
         }
         let state_commitments = state.pcd_commitment.to_value_object()?;
-        let mut new_encrypted_pcd: Map<String, Value> = Map::with_capacity(hash2values_map.len());
+        let mut new_encrypted_pcd: Map<String, Value> = state_commitments.iter()
+            .map(|(field, _)| {
+                (field.clone(), Value::Null)
+            })
+            .collect();
 
         for (hash, value) in hash2values_map {
             // Check the hash in pcd_commitment, get the corresponding field name