Smart-card based access control system with improved security
First Claim
1. A smart card comprising:
- a first terminal for receiving an input signal including first and second scrambled signal components;
a second terminal for providing an output signal;
means for processing said first scrambled signal component for producing a first descrambled processed signal, and being responsive to said first descrambled processed signal for processing said second scrambled signal component for producing a second descrambled processed signal; and
means for combining said first scrambled signal component of said input signal and said second descrambled processed signal to produce said output signal.
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Accused Products
Abstract
A smart card that includes a descrambler for descrambling entitlement information and data provides improved access control by controlling the manner in which the entitlement information portion of the data stream is passed through the smart card. Entitlement data that is descrambled and used in the smart card for functions such as key generation is reinserted in scrambled form in the high speed output data signal from the smart card. A variable delay device is included in the smart card for controlling when scrambled entitlement data is reinserted into the data stream. Varying the delay permits establishing a desired timing relationship between the reinserted data and other data in the data stream that is output from the smart card. For example, scrambled entitlement data in the output data stream can be made to exhibit substantially the same timing relationship to other data that exists in the input data stream.
217 Citations
19 Claims
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1. A smart card comprising:
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a first terminal for receiving an input signal including first and second scrambled signal components; a second terminal for providing an output signal; means for processing said first scrambled signal component for producing a first descrambled processed signal, and being responsive to said first descrambled processed signal for processing said second scrambled signal component for producing a second descrambled processed signal; and means for combining said first scrambled signal component of said input signal and said second descrambled processed signal to produce said output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. Signal processing apparatus comprising:
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(a) a signal processing channel for processing a digital input signal having a first scrambled signal component and a second scrambled signal component; (b) means for coupling said input signal to a removable smart card assembly, said smart card assembly processing said first scrambled signal component for producing a first descrambled signal internal to said card assembly, said smart card assembly processing, in response to said first descrambled signal, said second scrambled signal component for producing a second descrambled signal and said smart card assembly combining said first scrambled signal component of said input signal and said second descrambled signal component to produce an output signal; (c) means for receiving from said smart card assembly said output signal; and (d) means for processing said second descrambled signal component to generate a signal suitable for display.
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19. A method for signal processing, said method comprising:
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(a) receiving a digital input signal having a first scrambled signal component and a second scrambled signal component; (b) coupling said input signal to a removable smart card assembly for processing said first scrambled signal component to produce a first descrambled signal internal to said smart card assembly, and for processing, in response to said first descrambled signal, said second scrambled signal component for producing a second descrambled signal and for combining said first scrambled signal component of said input signal and said second descrambled signal component to produce an output signal; (c) receiving from said smart card assembly said output signal; and (d) processing said second descrambled signal component to generate a signal suitable for display.
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Specification