A computer-readable medium contains computer-readable codes as a program to execute a method of a mobile device, and the method includes unlocking the mobile device for the user to access a normal mode according to a password input from the user in a security check process of a security mode, and unlocking the mobile device for the user to access the normal mode according to an exceptional condition of the security mode, wherein the exceptional condition comprises a wireless communication, in which the mobile device wirelessly communicates with the external network, and an area condition, in which the mobile device is located.