System for determining successful reception of a message
First Claim
1. A method for determining that all of a scrambled message has been successfully received, the scrambled message being scrambled in accordance with a scrambling key and being capable of being descrambled in accordance with a descrambling key, descrambling key generating information for generating the descrambling key being comprised within a control message (ECM) associated with the scrambled message, the method comprising:
- providing a scrambled message scrambled in accordance with a scrambling key;
generating an unmodified ECM comprising descrambling key generating information for generating a descrambling key for descrambling the scrambled message;
generating a first derived value based on the scrambled message using a first value derivation function;
applying a first modification function to the unmodified ECM, the first modification function being based, at least in pan, on the first derived value, thereby producing a modified ECM;
transmitting the scrambled message and the modified ECM to a receiver; and
performing, at the receiver, the following steps;
generating a second derived value based on the received scrambled message using a second value derivation function;
applying a second modification function to the modified ECM, the second modification function being based, at least in pan, on the second derived value and being an inverse of the first modification function, thereby producing the unmodified ECM; and
employing the unmodified ECM to determine that all of the message has been successfully received.
9 Assignments
0 Petitions
Accused Products
Abstract
A method for determining that all of a scrambled message has been successfully received, the scrambled message being scrambled in accordance with a scrambling key and being capable of being descrambled in accordance with a descrambling key, descrambling key generating information for generating the descrambling key being included within a control message (ECM) associated with the scrambled message. The method includes providing a scrambled message scrambled in accordance with a scrambling key, generating an unmodified ECM including descrambling key generating information for generating a descrambling key for descrambling the scrambled message, generating a first derived value based on the scrambled message using a first value derivation function, applying a first modification function to the unmodified ECM, the first modification function being based, at least in part, on the first derived value, thereby producing a modified ECM, transmitting the scrambled message and the modified ECM to a receiver, and performing, at the receiver, the following steps: generating a second derived value based on the received scrambled message using a second value derivation function, applying a second modification function to the modified ECM, the second modification function being based, at least in part, on the second derived value and being an inverse of the first modification function, thereby producing the unmodified ECM, and employing the unmodified ECM to determine that all of the message has been successfully received. Related apparatus and methods are also provided.
-
Citations
22 Claims
-
1. A method for determining that all of a scrambled message has been successfully received, the scrambled message being scrambled in accordance with a scrambling key and being capable of being descrambled in accordance with a descrambling key, descrambling key generating information for generating the descrambling key being comprised within a control message (ECM) associated with the scrambled message, the method comprising:
-
providing a scrambled message scrambled in accordance with a scrambling key;
generating an unmodified ECM comprising descrambling key generating information for generating a descrambling key for descrambling the scrambled message;
generating a first derived value based on the scrambled message using a first value derivation function;
applying a first modification function to the unmodified ECM, the first modification function being based, at least in pan, on the first derived value, thereby producing a modified ECM;
transmitting the scrambled message and the modified ECM to a receiver; and
performing, at the receiver, the following steps;
generating a second derived value based on the received scrambled message using a second value derivation function;
applying a second modification function to the modified ECM, the second modification function being based, at least in pan, on the second derived value and being an inverse of the first modification function, thereby producing the unmodified ECM; and
employing the unmodified ECM to determine that all of the message has been successfully received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A system for determining that all of a scrambled message has been successfully received, the scrambled message being scrambled in accordance with a scrambling key and being capable of being descrambled in accordance with a descrambling key, descrambling key generating information for generating the descrambling key being comprised within a control message (ECM) associated with the scrambled message, the system comprising:
-
a scrambler for scrambling a message in accordance with a scrambling key, thereby producing a scrambled message;
an ECM generator for generating an unmodified ECM comprising descrambling key generating information for generating a descrambling key for descrambling the scrambled message;
first value derivation apparatus for generating a first derived value based on the scrambled message using a first value derivation function;
first modifying apparatus for applying a first modification function to the unmodified ECM, the first modification function being based, at least in part, on the first derived value, thereby producing a modified ECM;
a transmitter for transmitting the scrambled message and the modified ECM to a receiver, the receiver comprising;
second value derivation apparatus for generating a second derived value based on the received scrambled message using a second value derivation function;
second modifying apparatus for applying a second modification function to the modified ECM, the second modification function being based, at least in part, on the second derived value and being an inverse of the first modification function, thereby producing the unmodified ECM; and
employing apparatus for employing the unmodified ECM to determine that all of the message has been successfully received. - View Dependent Claims (21, 22)
-
Specification