Abstract: A system for providing visual display security on a general-purpose computer, the general-purpose computer capable of running an operating system and an application, the operating program system and application program presenting a user interface in the form of display windows, includes a display window having a default display characteristic and a computer security program operating on the general purpose computer. The computer security program altering the default display characteristic to a modified display characteristic, the modified display characteristic rendering the display window unreadable to a human eye. The system also includes an optical filter matched to the modified display characteristic so that the display window becomes readable when viewed through the optical filter.