Shingo Hasegawa Hiroyuki Hatanaka Shuji Isobe Eisuke Koizumi Hiroki Shizuya Making Cryptographic Primitives Harder. 330-337 2008 91-A IEICE Transactions 1 http://dx.doi.org/10.1093/ietfec/e91-a.1.330 db/journals/ieicet/ieicet91a.html#HasegawaHIKS08