On Random Coding Error Exponents of Watermarking Codes

Merhav, Neri

HP Development Company

关键词: steganography;    watermarking;    information hiding;    error exponent;    random coding;   

RP-ID  :  HPL-98-169

学科分类：计算机科学（综合）

美国|英语

来源: HP Labs

【 摘 要 】

Watermarking codes are analyzed from an information- theoretic viewpoint as a game between an information hider and an active attacker. While the information hider embeds a secret message (watermark) in a covertext message (typically, text, image, sound, or video stream) within a certain distortion level, the attacker processes the resulting watermarked message, within limited additional distortion, in attempt to invalidate the watermark. For a memoryless covertext source, we provide a single-letter characterization of the minimax-maximin game of the random coding error exponent associated with the average probability of erroneously decoding the watermark. This single-letter characterization is in effect because there is a "memoryless saddle point" in this game: The information hider utilizes a memoryless channel to generate random codewords for every covertext message, whereas the attacker implements a memoryless channel to disrupt the watermark information hidden in the covertext. 22 Pages