Dan Boneh Shai Halevi Nick Howgrave-Graham The Modular Inversion Hidden Number Problem. 36-51 2001 conf/asiacrypt/2001 ASIACRYPT http://link.springer.de/link/service/series/0558/bibs/2248/22480036.htm db/conf/asiacrypt/asiacrypt2001.html#BonehHH01