Methods for preventing unauthorized scripting. The invention generates a human interactive proof to distinguish a human from a machine by generating a random set of characters and altering each of the characters individually to inhibit computerized character recognition. The invention also includes concatenating the altered characters into a character string to be rendered to a user as a test. The character string may be altered to further inhibit computerized character recognition. Other aspects of the invention are directed to computer-readable media for use with the methods.