Cascading dynamic crypto periods
First Claim
1. A computer-implemented method for encrypting a data transmission stream using cascading dynamic crypto periods, the method comprising:
- sending a first set of functions to a recipient device for use during a first crypto period, the first crypto period comprising a number of sub-crypto periods correlated to a number of functions included in the first set of functions, wherein the plurality of sub-crypto periods comprises at least a first sub-crypto period and a second sub-crypto period, and wherein the first sub-crypto period is a discrete portion of the first crypto period and the second sub-crypto period is a second discrete portion of the first crypto period;
sending a first control word to the recipient device;
encrypting the first sub-crypto period of the data transmission stream using the first control word;
sending the first sub-crypto period of the encrypted data transmission stream to the recipient device;
generating a first derived control word, wherein the first derived control word is generated by applying a first function from the first set of functions to retrieved data;
encrypting the second sub-crypto period of the data transmission stream using the first derived control word; and
sending the second sub-crypto period of the encrypted data transmission stream to the recipient device.
3 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods for performing cascading dynamic crypto periods are disclosed. In embodiments, a control word and a set of functions is transmitted between a head-end and recipient devices at the beginning of a crypto period. The crypto period is divided into a discrete number of sub-crypto periods. The control word used to encrypt and decrypt the broadcast content is changed during each sub-crypto period. At the end of the first sub-crypto period, a derived control word is generated by passing the original control word to a function in the set of functions in order to generate a derived control word at the first transition between sub-crypto periods. The derived control word is used for encryption and decryption of the broadcasted content during the second sub-crypto period. Upon transitioning to the third sub-control-period, the derived control word is input into another function to produce a second derived control word.
-
Citations
66 Claims
-
1. A computer-implemented method for encrypting a data transmission stream using cascading dynamic crypto periods, the method comprising:
-
sending a first set of functions to a recipient device for use during a first crypto period, the first crypto period comprising a number of sub-crypto periods correlated to a number of functions included in the first set of functions, wherein the plurality of sub-crypto periods comprises at least a first sub-crypto period and a second sub-crypto period, and wherein the first sub-crypto period is a discrete portion of the first crypto period and the second sub-crypto period is a second discrete portion of the first crypto period; sending a first control word to the recipient device; encrypting the first sub-crypto period of the data transmission stream using the first control word; sending the first sub-crypto period of the encrypted data transmission stream to the recipient device; generating a first derived control word, wherein the first derived control word is generated by applying a first function from the first set of functions to retrieved data; encrypting the second sub-crypto period of the data transmission stream using the first derived control word; and sending the second sub-crypto period of the encrypted data transmission stream to the recipient device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A computer-implemented method for decrypting an encrypted data transmission stream using cascading dynamic crypto periods, the method comprising:
-
receiving, at a recipient device, a first set of functions comprising a plurality of functions, wherein the plurality of functions is correlated to a number of sub-crypto periods; receiving, at the recipient device, a first control word; receiving, at the recipient device, a first portion of an encrypted data transmission, wherein the first portion of the encrypted data transmission stream is encrypted using the first control word and represents a first sub-crypto period of the encrypted data transmission stream, wherein the first sub-crypto period is a discrete portion of a crypto period; generating a first portion of a clear data stream by decrypting the first portion of the encrypted data transmission stream using the first control word; receiving, at the recipient device, a second portion of the encrypted data transmission stream, wherein the second portion of the encrypted data transmission stream is encrypted using a first derived control word and represents a second sub-crypto period of the encrypted data transmission stream, wherein the second sub-crypto period is a discrete portion of the crypto period; generating the first derived control word by applying a first function from the first set of functions to retrieved data; and generating a second portion of the clear data stream by decrypting the second portion of the encrypted data transmission stream using the first derived control word. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
-
-
40. A system for encrypting and decrypting a data transmission stream using cascading dynamic crypto periods, the system comprising:
a head-end device for receiving and encrypting a clear data transmission stream, the head-end comprising device; at least a first processor; and a first memory in communication with and readable by at least the first processor, wherein the first memory comprises instructions that, when executed by at least the first processor, cause the at least one processor to perform a first method comprising; sending a first set of functions to a recipient device for use during a first crypto period, the first crypto period comprising a number of sub-crypto periods correlating to a number of functions in the first set of functions, wherein the number of sub-crypto periods comprises at least a first sub-crypto period and a second sub-crypto period, and wherein the first sub-crypto period is a first discrete portion of the first crypto period and the second sub-crypto period is a second discrete portion of the first crypto period; sending a first control word to the recipient device; encrypting the first sub-crypto period of the data transmission stream using the first control word; sending the first sub-crypto period of the encrypted data transmission stream to the recipient device; generating a first derived control word, wherein the first derived control word is generated by applying a first function from the first set of functions to the first control word; encrypting the second sub-crypto period of the data transmission stream using the first derived control word; and sending the second sub-crypto period of the encrypted data transmission stream to the recipient device. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
-
55. A recipient device for receiving and decrypting an encrypted data stream, the recipient device comprising:
-
a processor; and a memory in communication with and readable by the processor, wherein the memory comprises instructions that, when executed by the processor, cause the processor to perform a method, the method comprising; receiving a first set of functions comprising a plurality of functions, wherein a number of sub-crypto periods correlates to a number of functions included in the plurality of functions; receiving a first control word; receiving a first portion of an encrypted data transmission, wherein the first portion of the encrypted data transmission stream is encrypted using the first control word and represents a first sub-crypto period of the encrypted data transmission stream, wherein the first sub-crypto period is a discrete portion of a crypto period; generating a first portion of a clear data stream by decrypting the first portion of the encrypted data transmission stream using the first control word; receiving a second portion of the encrypted data transmission stream, wherein the second portion of the encrypted data transmission stream is encrypted using a first derived control word and represents a second sub-crypto period of the encrypted data transmission stream, wherein the second sub-crypto period is a discrete portion of the crypto period; generating the first derived control word by applying a first function from the first set of functions to the first control word; and generating a second portion of the clear data stream by decrypting the second portion of the encrypted data transmission stream using the first derived control word. - View Dependent Claims (56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66)
-
Specification