Jae Hong Seo Tetsutaro Kobayashi Miyako Ohkubo Koutarou Suzuki Anonymous Hierarchical Identity-Based Encryption with Constant Size Ciphertexts. 215-234 2009 Public Key Cryptography http://dx.doi.org/10.1007/978-3-642-00468-1_13 conf/pkc/2009 db/conf/pkc/pkc2009.html#SeoKOS09