A New Method for Known Plaintext Attack of FEAL Cipher
We propose a new known plaintext attack of FEAL cipher. Our method differs from previous statistical ones in point of deriving the extended key in definite way. As a result, it is possible to break FEAL-4 with 5 known plaintexts and FEAL-6 with 100 known plaintexts respectively. Moreover, we show a method to break FEAL-8 with 215 known plaintexts faster than an exhaustive search.
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