Patent ID: 8948387
Filing Date: 2015-02-03
Classification: G09C,H04L,H04W

Abstract:
1. A communication system having a first and a second communicating device operable to send and receive a plurality of data units through a communication channel, said plurality of data units comprising data units encrypted using a security key, said first device comprising a first security key generator generating a first embodiment of said key independently of a second embodiment of said key generated by a second security key generator of said second device, said second embodiment being generated independently of said first embodiment, said first embodiment depending on characterizing a first average of N consecutive instances of a transmission quality parameter of said communication channel when receiving a first set of data units sent by said second device not encrypted using said key, where N is an integer greater than one (1), said second embodiment depending on characterizing a second average of N consecutive instances of the transmission quality of said communication channel when receiving a second set of data units sent by said first device not encrypted by said key, said first set being different from said second set, wherein said generating said first embodiment of said key depends on a variation over time of said transmission quality parameter and said generating said second embodiment of said key depends on a variation over time of said transmission quality, wherein said first and second security key generators additionally generate respective embodiments of an additional security key at said first device and said second device, wherein said respective embodiments of said additional security key are different from said first embodiment and said second embodiment of the security key, a respective embodiment of said additional security key being used for decrypting received data units encrypted by said first embodiment of the security key, said first device sending a valid key confirmation to said second device, wherein a valid key confirmation is encrypted using said first embodiment of the security key, and wherein a physical parameter of said communication channel is changed at least once during transmission of said first and second set of data units not encrypted using said security key.