Patent ID: 7436955

Claim:
An encryption method comprising a step of encrypting and transmitting a data stream from a sender to a receiver via a channel after at least a part of said data stream is encrypted, said step of encrypting and transmitting comprising: adjusting encryption attributes during transmission based upon a complexity consideration of a situation of the sender, the receiver and the channel; encrypting the data stream according to the adjusted encryption attributes; and transmitting said encrypted data stream and information of said encryption attributes to said receiver, wherein said step of adjusting encryption attributes comprises: determining whether there is a need to adjust said encryption attributes based on quality of the channel; if so, adjusting the encryption attributes wherein said step of adjusting encryption attributes comprises: determining whether current BER of the channel has increased by a first predetermined amount; if said current BER of the channel has increased by the first predetermined amount, adjusting the encryption attributes to reduce an error propagation length of the encryption; determining whether the current BER of the channel has decreased by a second predetermined amount; and if said current BER of the channel has decreased by the second predetermined amount, adjusting the encryption attributes to increase the error propagation length of the encryption.