Doug Szajda Barry G. Lawson Jason Owen Hardening Functions for Large Scale Distributed Computations. 216-224 2003 conf/sp/2003 IEEE Symposium on Security and Privacy http://csdl.computer.org/comp/proceedings/sp/2003/1940/00/19400216abs.htm db/conf/sp/sp2003.html#SzajdaLO03