TY - CONF T1 - Visible Encryption: Using Paper as a Secure Channel T2 - Security and Watermarking of Multimedia Contents Y1 - 2003 A1 - Norberto Degara-Quintela A1 - Fernando Pérez-González ED - Ping W. Wong ED - Edward J. Delp KW - 2-D-Bar-Codes KW - data-hiding KW - print-&-scan KW - Two-dimensional-modulations KW - visible-encryption JF - Security and Watermarking of Multimedia Contents T3 - Proc. of SPIE CY - Santa Clara, USA VL - 5020 ER -