Krystian Matusiewicz Josef Pieprzyk Norbert Pramstaller Christian Rechberger Vincent Rijmen Analysis of simplified variants of SHA-256. 123-134 2005 conf/weworc/2005 WEWoRC db/conf/weworc/weworc2005.html#MatusiewiczPPRR05 http://subs.emis.de/LNI/Proceedings/Proceedings74/article3803.html