Patent ID: 6539094
Filing Date: 2003-03-25
Classification: H04L,H04N

Abstract:
Apparatus for transmitting data in asynchronous and isochronous modes to a receiving device, comprising:ciphering means for ciphering the data to be transmitted in at least the isochronous mode by the use of first and second cipher keys, said first cipher key being a session key that is invariable during a data transmission session, said second cipher key being a time variable key that is updated on a cyclical basis during the data transmission session; packetizing means for packetizing the ciphered data into packets of the isochronous mode; and transmitting means for transmitting the packets of ciphered data from said packetizing means to the receiving device; wherein said apparatus transmits updated second key information in a cyclical manner to the receiving device to enable the receiving device to generate the updated time variable key to decipher the ciphered data.