Norihisa Isogai Takashi Matsunaka Atsuko Miyaji Optimized Chi<sup>2</sup>-Attack against RC6. 16-32 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2846&spage=16 2003 conf/acns/2003 ACNS db/conf/acns/acns2003.html#IsogaiMM03