A method for communicating in a network is presented. The method includes
encapsulating content from a plurality of high level data units from a
high level layer to generate a stream; dividing the stream into a
plurality of segments; individually encrypting at least some of the
segments, wherein an encrypted segment includes a plurality of encrypted
blocks, and at least some of the encrypted blocks are encrypted based on
at least one other encrypted block within the encrypted segment; and
supplying low level data units to a physical layer that handles physical
communication over the network, at least some of the low level data units
each including a plurality of encrypted segments.