David Galindo Paz Morillo Carla Ràfols Breaking Yum and Lee Generic Constructions of Certificate-Less and Certificate-Based Encryption Schemes. 81-91 2006 conf/europki/2006 EuroPKI http://dx.doi.org/10.1007/11774716_7 db/conf/europki/europki2006.html#GalindoMR06