tailieunhanh - Báo cáo hóa học: " Research Article How Reed-Solomon Codes Can Improve Steganographic Schemes"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article How Reed-Solomon Codes Can Improve Steganographic Schemes | Hindawi Publishing Corporation EURASIP Journal on Information Security Volume 2009 Article ID 274845 10 pages doi 2009 274845 Research Article How Reed-Solomon Codes Can Improve Steganographic Schemes Caroline Fontaine and Fabien Galand CNRS IRISA-TEMICS Group Campus de Beaulieu 35 042 Rennes Cedex France Correspondence should be addressed to Caroline Fontaine Received 31 July 2008 Accepted 6 November 2008 Recommended by Miroslav Goljan The use of syndrome coding in steganographic schemes tends to reduce distortion during embedding. The more complete model comes from the wet papers J. Fridrich et al. 2005 and allow to lock positions which cannot be modified. Recently binary BCH codes have been investigated and seem to be good candidates in this context D. Schonfeld and A. Winkler 2006 . Here we show that Reed-Solomon codes are twice better with respect to the number of locked positions in fact they are optimal. First a simple and efficient scheme based on Lagrange interpolation is provided to achieve the optimal number of locked positions. We also consider a new and more general problem mixing wet papers locked positions and simple syndrome coding low number of changes in order to face not only passive but also active wardens. Using list decoding techniques we propose an efficient algorithm that enables an adaptive tradeoff between the number of locked positions and the number of changes. Copyright 2009 C. Fontaine and F. Galand. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. Introduction Steganography aims at sending a message through a covermedium in an undetectable way. Undetectable means that nobody except the intended receiver of the message should be able to tell if the medium is carrying a message or not 1 . Hence if we speak about still images as cover-media