文章基本信息

标题：Digital Semipublic Watermarking
本地全文：下载
作者：Valery Korzhik ; Guillermo Morales-Luna ; Dmitry Marakov 等
期刊名称：Informatica
印刷版ISSN：1514-8327
电子版ISSN：1854-3871
出版年度：2002
卷号：26
期号：3
页码：279-286
出版社：The Slovene Society Informatika, Ljubljana
摘要：The theory Information Hiding and in particular Watermarking (WM) still remains uncompleted. There have been some advances in asymptotic theory concerning capacity of WM as well as in some practical proposals, mainly where WM is applied without any theory. Most of times, references are made to public watermarking, in which the watermark detector does not require any secret key at all. In this paper, our contribution is a WM that we name semipublic watermarking. This is a scenario in which any ordinary user is enabled to detect WM without any secret key, if the message is not subject of attack trying toremove its WM. Moreover, at any time, the owner of WM is able to detect WM even after such an attack. We propose two methods of semipublic WM and we calculate the probabilities Pm, of missing WM (when WM is present, indeed), and Pfa of WM false alarm (when WM is absent but its presence is supposed). The first method guarantees that both Pm and Pfa converge to zero as the number N of WM elements increases, only if the distortion constraints are very strong. In second method also Pm, Pfa converge to zero as N increases, for any distortion constraints, but it is required the so called property of quadratic compensation: In order to compensate an m times increase of the distortion constraint ``signal-to-noise ratio'', the number at WM elements should increase m^2 times. Although we consider just additive noise attacks, our results are useful since they provide lower bounds for WM reliability for any optimal attack with given distortion constraints
关键词：information security; copyright protection; information hiding; watermarking