Shoko Imaizumi Masaaki Fujiyoshi Yoshito Abe Hitoshi Kiya Collusion Attack-Resilient Hierarchical Encryption of JPEG 2000 Codestreams with Scalable Access Control. 137-140 2007 ICIP (2) http://dx.doi.org/10.1109/ICIP.2007.4379111 conf/icip/2007 db/conf/icip/icip2007-2.html#ImaizumiFAK07