Collision detection problem between prefab and gameobject

I can't wrap my head around this problem. I've tried adding onCollisionEnter and onTriggerEnter on both my cube and my bullet prefab but neither of them detects a collision between them. I've searched on google on this problem but couldn't find a solution that worked.

This is my script on my cube gameobject.

 using UnityEngine;
 using System.Collections;
 
 public class testcollision : MonoBehaviour {
 
     public GameObject bullet;
 
     void onTriggerEnter(Collider other) {
         if(other.gameObject.tag == "bullet" ) {
             Destroy(this.gameObject);
         }
     }
 
     void update() {
         
     }
 }

This is the inspector menu on the cube gameobject: http://i.imgur.com/M0WDZIX.png

This is how my bullet is being made. It gets shot from my player character.

 using UnityEngine;
 using System.Collections;
 
 public class AutoattackBULLET : MonoBehaviour {
 
     public GameObject Bullet_Emitter;
 
     public GameObject Bullet;
 
     public float Bullet_Foward_Force;
 
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () {
 
         if(Input.GetKeyDown("a")) {
             GameObject Temp_bullet_handler;
             Temp_bullet_handler = Instantiate (Bullet, Bullet_Emitter.transform.position, Bullet_Emitter.transform.rotation) as GameObject;
 
             Temp_bullet_handler.transform.Rotate(Vector3.left * 90);
 
             Rigidbody Temp_Rigidbody;
             Temp_Rigidbody = Temp_bullet_handler.GetComponent<Rigidbody>();
 
             Temp_Rigidbody.AddForce(transform.right * Bullet_Foward_Force); //use transform.right
 
             Destroy(Temp_bullet_handler, 0.4f);
         }
     
     }
 }

This is the bullet prefab's inspector menu: http://i.imgur.com/sFiAlZU.png

The bullet does bounce off the cube but I can't get a collision check anywhere.