Gautam Singaraju Brent Hoon Kang Concord: A Secure Mobile Data Authorization Framework for Regulatory Compliance. 91-102 2008 LISA http://www.usenix.org/events/lisa08/tech/full_papers/singaraju/singaraju.pdf conf/lisa/2008 db/conf/lisa/lisa2008.html#SingarajuK08