Methods and systems are provided for authenticating a human user. A memory can store a plurality of images and can store account information for a plurality of users. The account information can include personal image information for at least some of the users. A processor can receive a communication including an indication of a desire of a user to be authenticated, access an account of the user, modify the plurality of images to form a plurality of modified images, provide the plurality of modified images to the user, receive trial personal image information from the user, and compare the personal image information stored in the memory to the trial personal image information received from the user. The processor can authenticate the user if the personal image information stored in the memory is the same as the trial personal image information.