Takashi Nishide Kazuki Yoneyama Kazuo Ohta Attribute-Based Encryption with Partially Hidden Ciphertext Policies. 22-32 2009 92-A IEICE Transactions 1 http://search.ieice.org/bin/summary.php?id=e92-a_1_22&category=A&year=2009&lang=E&abst= db/journals/ieicet/ieicet92a.html#NishideYO09