A method of inputting a user input access combination in order to gain authorized entry into a secure location comprises providing an input device having first and second input keys as well as a display, randomly generating a first character and a second character on the display, inputting the user input access combination into the input device, and comparing the user input access combination with an authorized access combination. The user input access combination includes a first user input character and a second user input character. The step of inputting the user input access combination comprises pressing the first input key to change the first randomly generated character to the first user input character, and pressing the second input key to change the second randomly generated character to the second user input character.