The disclosure relates to various data processing terminals capable of operating in different modes each of which is granted with different authorities to access hardware or software elements of the terminals. More particularly, a terminal includes a lock system operating in a lock mode and a main system operating in an unlock mode, and erases an entire or a selected portion of results obtained by running operations in the lock mode, when a terminal switches from a lock mode to an unlock mode with greater access authority. Because potentially malicious computer codes which may be impregnated into such results are erased before switching to an unlock mode, the terminal enhances an integrity and a security of a terminal, and improves privacy of a user by preventing loss or unintended disclosure of private data stored in a terminal.
