@InProceedings{l00-p280-291, AUTHOR = {Matthias Krause and Hans-Ulrich Simon}, TITLE = {Determining the Optimal Contrast for Secret Sharing Schemes in Visual Cryptography}, YEAR = 2000, BOOKTITLE = {Proc.~of the 4th Latin American Symposium on Theoretical Informatics (LATIN'00)}, ADDRESS = {Punta del Este, Uruguay}, PAGES = {280--291}, KEYWORDS = {}}