Rapid decryption of data by key synchronization and indexing
First Claim
1. A method of encrypting data for rapid decryption, the method comprising the steps of:
- sequentially generating a plurality of random numbers;
sequentially generating a plurality of index numbers respectively associated with said random numbers, wherein a first index number is initially generated and said index numbers increment by a predefined value; and
calculating a plurality of cyphered seeds according to a combination of each one of said random numbers and each one of said respectively associated index numbers.
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Accused Products
Abstract
A satellite broadcast conditional access system with key synchronization uses indexing of an authorization stream to quickly restart the decrypting process after short carrier fades and after carrier switches. The authorization stream includes cyphered seeds and index numbers which are sequentially sent to a group of receivers. The same authorization stream can also be broadcast multiple times to the group of receivers. A conditional access server selects a starting index number and increments the index number by a predefined value. The receivers have a memory to save the current index number for the authorization stream. Any receiver that loses its connection to the broadcast and thereafter reestablishes its connection can retrieve the latest index number being issued in the authorization stream and compare it with the stored index number. When the index numbers match or are within a defined threshold, the receiver will continue to decypher the seeds and decrypt the transport stream.
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Citations
36 Claims
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1. A method of encrypting data for rapid decryption, the method comprising the steps of:
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sequentially generating a plurality of random numbers;
sequentially generating a plurality of index numbers respectively associated with said random numbers, wherein a first index number is initially generated and said index numbers increment by a predefined value; and
calculating a plurality of cyphered seeds according to a combination of each one of said random numbers and each one of said respectively associated index numbers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of encrypting data for rapid decryption, the method comprising the steps of:
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sequentially generating a plurality of random numbers;
sequentially generating a plurality of index numbers respectively associated with said random numbers, wherein a first index number is initially generated and said index numbers increment by a predefined value;
calculating a plurality of cyphered seeds according to a combination of each one of said random numbers, each one of said respectively associated index numbers, and a plurality of serial numbers respectively associated with a group of receivers;
sending a group of cyphered seed and corresponding index number pairs from a server to said group of receivers during a flavor distribution period;
resending said group of cyphered seed and corresponding index number pairs to said group of receivers during said flavor distribution period;
repeating said sending and resending steps for a plurality of subsequent groups of cyphered seed and corresponding index number pairs to said group of receivers. extracting a cyphered seed using its serial number from said cyphered seed and index number pairs in each one of said receivers;
decyphering said cyphered seed and index number pairs in each one of said receivers;
storing said decyphered seed and index number pair in a memory of each one of said receivers;
repeating said decyphering and storing steps for a plurality of subsequent cyphered seed and index number pairs until an occurrence of a reset;
after said reset, decyphering a most recently received index number and comparing said most recently received index number with said stored index number; and
continuing with said decyphering and storing steps if said most recently received index number is within a defined tolerance of said stored index number. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A system for encrypting and decrypting data, comprising:
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means for sequentially generating a plurality of random numbers and a plurality of index numbers respectively associated with said random numbers, wherein a first index number is initially generated and said index numbers increment by a predefined value;
means for calculating a plurality of cyphered seeds according to a combination of each one of said random numbers, each one of said respectively associated index numbers, and a plurality of serial numbers respectively associated with a group of receivers;
means for sending a group of cyphered seed and corresponding index number pairs from a server to said group of receivers during a flavor distribution period, and resending said group of cyphered seed and corresponding index number pairs to said group of receivers during said flavor distribution period;
means for extracting a cyphered seed and corresponding index number from said cyphered seed and index number pairs, wherein at least one of said serial numbers is used to extract said cyphered seed;
a decrypter in operative communication with said extracting means receives said extracted cyphered seed and said index number and decyphers said cyphered seed into a decyphered seed;
a memory device in operative communication with said decrypter receives and stores said decyphered seed and index number;
means for setting a reset command and thereafter comparing a new index number with said stored index number according to a defined tolerance. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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31. A server for encrypting data, comprising:
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means for sequentially generating a plurality of random numbers and a plurality of index numbers respectively associated with said random numbers, wherein a first index number is initially generated and said index numbers increment by a predefined value;
means for calculating a plurality of cyphered seeds according to a combination of each one of said random numbers and each one of said respectively associated index numbers; and
means for sending a group of cyphered seed and corresponding index number pairs from a server to a respective group of receivers during a flavor distribution period, and resending said group of cyphered seed and corresponding index number pairs to said respective group of receivers during said flavor distribution period. - View Dependent Claims (32, 33, 34)
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35. An integrated receiver decoder for decrypting data, comprising:
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means for extracting a cyphered seed and a corresponding index number from a group of cyphered seed and index number pairs;
wherein a plurality of serial numbers are used to generate a plurality of cyphered seeds and wherein at least one of said serial numbers is used to extract said cyphered seed;
a decrypter in operative communication with said extracting means receives said extracted cyphered seed and said corresponding index number and decyphers said cyphered seed into a decyphered seed;
a memory device in operative communication with said decrypter receives and stores said decyphered seed and index number; and
means for setting a reset command and thereafter comparing a new index number with said stored index number according to a defined tolerance. - View Dependent Claims (36)
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Specification