Abstract: An example method includes displaying, by a first computing device (110) comprising a display (114), each of one or more characters at a location of one or more locations within the display (114); receiving, by the first computing device (110) from a second computing device (150), data indicating at least one selected location of the one or more locations within the display (114); making a determination, by the first computing device (110), that at least one character of the one or more characters matches a predetermined authentication code, wherein each character of the at least one character is displayed at a location of the at least one selected location within the display (114); and after making the determination, sending, by the first computing device (110), a message authorizing a financial transaction. Corresponding operations of the second computing device (150) are disclosed herein.