Mustafa Kesal Mehmet Kivanç Mihçak Ramarathnam Venkatesan An improved attack analysis on a public-key spread spectrum watermarking. 41-45 2004 conf/mmsec/2004 MM&Sec http://doi.acm.org/10.1145/1022431.1022440 db/conf/mmsec/mmsec2004.html#KesalMV04