module and second module may include additional circuitry for scrambling bits between groups application_number US 19823908 A description the detailed description will begin with a simplified u201c one dimensional u201d encryption scheme that introduces the concept of a stream of what appears to an observer of the inter module communication channel as random symbol data across the physical interface between two modules that are communicating refer to fig1 a and 1b for this discussion note that for simplicity fig1 a and 1b show only the communication channel from module a to module b most real systems would have communication channels in both directions the return channel may be implemented by replicating the outbound logic of module a in module b and replicating the inbound logic of module b in module a in this example the symbol width is 8 bits four physical signals carry information from module a to module b these physical signals will be called lanes labeled l 0 through l 3 and could be implemented as individual wires using single ended signaling technology or using wire pairs in the case of double ended signaling regardless of the signaling technique used the four lanes carry four bits of information per bit time therefore each 8 bit symbol designated s 7 0 is split into two 4 bit sub symbols one sub symbol s 7 4 consists of the most significant nibble of the byte wide symbol and the other the least significant nibble s 3 0 each symbol in a stream of symbols is written into outbound buffer 116 by some logic.