A method where a Downloadable Conditional Access System Provisioning Server (DPS) detects a duplicated secure micro is provided. A method of detecting a duplicated secure micro, the method including: generating authentication time difference information associated with a value of a difference between a time when a host is finally authenticated in a first address and a time when the host is authenticated in a second address; comparing the authentication time difference information with a first reference value and a second reference value, the second reference value being less than the first reference value; and determining whether the secure micro is duplicated based on a result of the comparing.