Linear cryptanalysis of block cipher Xenon
This paper cryptanalyzes 128-bit block cipher Xenon, which was designed by Chang-Hyi Lee and has been recently proposed by Korea to ISO 18033-3, an ongoing activity in ISO/IEC JTC1/SC27/WG2 for standardizing block cipher algorithms. We study security of Xenon against linear cryptanalysis and show highly biased linear approximate paths that hold with probability 1/2 +/- 2(-11) in the full 16-round Xenon. As a result, we can easily derive four-bit subkey information of Xenon using 2 23 known plaintexts with approximate success rate 84%. We also demonstrate a distinguishing attack of Xenon in a chosen plaintext scenario, which successfully reduces the number of required plaintext/ciphertext pairs of the attack. All these results were confirmed by computer experiments.
linear cryptanalysis cryptanalysis block cipher xenon iso