A storage device includes a substrate, at least one data storage element, a case, and at least one sensing pin. The substrate includes at least one security pad. The data storage element is mounted on the substrate. The case surrounds the substrate and the data storage element, and includes at least one contact structure for an electrical connection with the security pad. The sensing pin receives an electrical signal. A level of the electrical signal varies by detecting a change in a resistance according to whether the security pad is electrically connected to the contact structure. When at least a part of the case is removed, a level change of the electrical signal is detected, and a secure erase process for data stored in the data storage element is performed.