Covert timing channels codes for communication over interactive traffic

This paper presents the first practical perfectly-secure steganography codes for covert communication via packet timings across interactive traffic relayed over network queuing systems. It has recently been shown that sparse-graph linear codes followed by shaping techniques, combined with message-passing decoding, can enable practical timing channel codes with low symbol error rates near the information capacity of the famous ldquobits through queuesrdquo channel. Inspired by this new class of codes, we use an alternative shaping technique that employs random dithers and construct provably secure steganographic codes for communication using packet timings in interactive traffic. To validate the perfect secrecy of our steganographic codes, we model interactive traffic as a two-state Markov modulated Poisson process (MMPP) and show its goodness-of-fit.