Michel Abdalla Dario Catalano Céline Chevalier David Pointcheval Password-Authenticated Group Key Agreement with Adaptive Security and Contributiveness. 254-271 2009 AFRICACRYPT http://dx.doi.org/10.1007/978-3-642-02384-2_16 conf/africacrypt/2009 db/conf/africacrypt/africacrypt2009.html#AbdallaCCP09