Takashi Nishide Kazuki Yoneyama Kazuo Ohta Attribute-Based Encryption with Partially Hidden Encryptor-Specified Access Structures. 111-129 2008 ACNS http://dx.doi.org/10.1007/978-3-540-68914-0_7 conf/acns/2008 db/conf/acns/acns2008.html#NishideYO08