Method for providing security for a transmission of information through a plurality of frequency orthogonal subchannels

摘要

One embodiment of the present invention is a method for providing security for a transmission of information in an ADSL environment using a DMT modulation technique. The order of the frequency orthogonal subchannels used in the DMT technique is scrambled according to a permutation cipher. The key for this scrambling operation is scrambled with the subscriber's public key, and is encoded according to a CDMA technique for transmission through the ADSL channel approximately concurrently with the information. The encoded key and the DMT data subblocks are recovered from the secured transmission. The encoded key is decoded according to the CDMA technique to generate the decoded key. The decoded key is used to assign an order to the subblocks of data.