METHODS AND APPARATUS FOR RENDERING AN OPTICALLY ENCODED MEDIUM UNREADABLE AND TAMPER-RESISTANT

摘要

Methods and means for rendering optically readable media unreadable and tamp er resistant are disclosed. A method for this include providing the readout surface of the optically readable medium with a roughened surface by embossing, scratching, depositing a non-planar layer or the like which inhibits the readout of the medium (B). Applying a sublimable coating (200) to the roughened surface which results in a smooth surface which enables the readout of the media (C). Providing a barrier layer (200A) to the smoothed surface (D). When used, the barrier layer is removed exposing the sublimable coating (200) (E). This coating evaporates due to heating by the readout bea m and/or exposure to the atmosphere to expose the roughened surface rendering the media unreadable (F).