Abstract: In a system (600), a server (610) provides a digital signal processing function ƒ to an executing device (620) in an obfuscated form. The function ƒ includes a function cascade of signal processing functions ƒ1, 1?i?N to formula (I). The server includes a processor (612) for selecting a set of 2N invertible permutations pi, 1?i?2N; calculating a set of N functions g, where g, is functionally equivalent to formula (II) for 1?i?; and calculating a set of N?1 functions h, where h, is functionally equivalent to formula (III) for 2?i?N. The server includes means (614) for equipping the executing device with an execution device function cascade that includes formula (IV), where y1, . . . , yN are function parameters to formula (V), and means (616) for providing the functions g1, . . . gN to the executing device. The executing device includes means (626) for obtaining the functions g1, . . .

Abstract: A method of enhancing the security of a protection mechanism used in a product. When information (115) regarding a vulnerability in the protection mechanism is received from a person (100), the person (100) is given a reward (145) for supplying the information (115). The reward (145) comprises a portion of profits made on the product in a time period ranging from the moment of receiving the information (115) until a moment at which the information (115) becomes public knowledge.

Abstract: An optical switch apparatus (110) includes a light source (112) that emits light (114) to a light emitting diode (LED) (116) which is responsive to the light (114) from the light source (112). In response to receiving light (114) from the light source (112), the LED (116) has a biased condition in which the LED (116) is effective to conduct electrical current. The LED (116) also has an unbiased condition in the absence of receiving light from the light source. The switch apparatus (110) also includes a switch (124) operatively connected with the LED (116) and responsive to the condition of the LED (116). The LED (116) effects operation of the switch (124) in a first operative state when the LED (116) is in the biased condition. The LED (116) effects operation of the switch (124) in a second operative state different from the first operative state when the LED (116) is in the unbiased condition.

Abstract: An optical switch (10) comprises a body of resilient material (12) including resilient opaque material (16) and resilient light conducting material (14). The light conducting material (14) is arranged in rows (20) and columns (22) which intersect at junctures (30). At least one light transmitter (50) directs light into one end of the rows (20) and columns (22) and through the junctures (30). Each juncture (30) is deformable to modify the intensity of light transmitted through the juncture (30). At least one light receiver (52) receives the light transmitted through the juncture (30) and provides an output signal in response to the modified light intensity.