Isamu Teranishi Takuro Oyama Wakaha Ogata General Conversion for Obtaining Strongly Existentially Unforgeable Signatures. 191-205 2006 conf/indocrypt/2006 INDOCRYPT http://dx.doi.org/10.1007/11941378_14 db/conf/indocrypt/indocrypt2006.html#TeranishiOO06