The encryption algorithm KASUMI is referred to MISTY, proposed by Matsui, is a provably secure against Linear cryptoanalysis
and Differential attack. We attacked KASUMI without FL functions by using Higher Order Differential Attack. The necessary
order of Higher Order Differential Attack depends on the degree of F function and it is determined by the chosen plaintext.
We found effective chosen plaintext which enables the attack to 4 round KASUMI without FL functions. As the result, we can
attack it using 2nd order differentials. This attack needs about 1,416 chosen plaintexts.