@conference {pcomesan-iwdw11, title = {Witsenhausen{\textquoteright}s counterexample and its links with multimedia security problems}, booktitle = {International Workshop on Digital Watermarking (IWDW)}, year = {2011}, month = {October}, address = {Atlantic City, USA}, keywords = {control, Multimedia security, Witsenhausen{\textquoteright}s counterexample}, author = {Pedro Comesa{\~n}a and Fernando P{\'e}rez-Gonz{\'a}lez and Chaouki T. Abdallah} }