Design of high speed stegosystem based on trellis codes jointly with generalised Viterbi algorithm

摘要

© Technomathematics Research Foundation.One of the most promising direction in the design of high speed stegosystem was project HUGO based on the use of trellis codes (TC) and Viterbi Algorithm(VA) in the embedding procedure. However the optimality of VA was kept still unclear because a generic purpose of VA is to correct errors.We prove that optimality of embedding can be achieved with the use of generalised Viterbi algorithm(GVA) proposed by one of the authors of this paper about 30 years ago. Optimisation of the trellis code check matrix based on the use of GVA is also considered. The second goal of the current paper is to consider to use TC jointly with GVA in order to provide both security of a stegosystem and simultaneously their ability to correct errors which can be induced by an attacker in order to remove embedded information even in the case if the attacker is unable to detect a presence of hidden information (blind attack). We consider also a trade off between security and error correction. Experimental results show that it is possible to build a stegosystem with acceptable errorcorrection capabilities together with minimization of the embedding impact.