Assume you reserve a safe box for your valuable issues in a bank. To open the safe box two keys are there, one is with you and the other with the bank employee, you will not be able to open the safe box unless both keys are used. And even if you have the key you need to show your ID for the employee of the bank to verify your identity as the owner of the safe box. Indicate what design security principles (least privilege, layering, ..etc) is/are achieved by this? Explain your answer.