Le Trieu Phong Kaoru Kurosawa Wakaha Ogata New RSA-Based (Selectively) Convertible Undeniable Signature Schemes. 116-134 2009 AFRICACRYPT http://dx.doi.org/10.1007/978-3-642-02384-2_8 conf/africacrypt/2009 db/conf/africacrypt/africacrypt2009.html#PhongKO09