Abstract: An apparatus and a method for releasing a lock function set in advance by detecting a user's input in an electronic device increases the security level required to access the electronic device. A method for controlling the lock function in the electronic device includes determining pattern input information. After determining the pattern input information is valid by analysis with predetermined pattern information, the lock function is released. The pattern input information includes at least one of a pattern shape, a pattern input time, a pattern input position, and a pen pressure of a pattern. The apparatus includes a touchscreen configured for detecting gestures, use of a stylus within a pre-determined threshold, and touch. The device discerns whether input has been entered in a proper hidden region of the display, to reduce unauthorized access by someone observing the input pattern being entered.