Rosario Gennaro Shai Halevi Hugo Krawczyk Tal Rabin Threshold RSA for Dynamic and Ad-Hoc Groups. 88-107 2008 EUROCRYPT http://dx.doi.org/10.1007/978-3-540-78967-3_6 conf/eurocrypt/2008 db/conf/eurocrypt/eurocrypt2008.html#GennaroHKR08