AES Shortlist After testing and evaluation,shortlist in Aug 99: -MARS (IBM)-complex,fast,high security margin -RC6 (USA)-very simple,very fast,low security margin -Rijndael(Belgium)-clean,fast,good security margin -Serpent(Euro)-slow,clean,very high security margin -Twofish(USA)-complex,very fast,high security margin Then subject to further analysis comment Saw contrast between algorithms with -Few complex rounds vs.many simple rounds -which refined existing ciphers vs.new proposals 55 AES Shortlist  After testing and evaluation, shortlist in Aug 99: ─ MARS (IBM) - complex, fast, high security margin ─ RC6 (USA) - very simple, very fast, low security margin ─ Rijndael (Belgium) - clean, fast, good security margin ─ Serpent (Euro) - slow, clean, very high security margin ─ Twofish (USA) - complex, very fast, high security margin  Then subject to further analysis & comment  Saw contrast between algorithms with ─ Few complex rounds vs. many simple rounds ─ which refined existing ciphers vs. new proposals