Secure data transmission on a TDM isochronous network

A secure method for transmitting data on an isochronous network in which data is spread in successive frames in a manner known to the sender and receiver but unknown to other nodes on the network. In one embodiment, some or all bits which comprise a byte are transmitted in different channels (i.e. time slots) so that the bits which comprise a byte are spread over several channels in a pattern known to the sender and receiver but not to unauthorized parties on the network. This bit spreading can be performed in real time and without latency or performance problems. In another embodiment, the channel or channels assigned for communication between two nodes on the network change in a sequence known to the sending and receiving nodes but not known to unauthorized parties.