文章基本信息

标题：The Security of RC6 against Asymmetric Chi-square Test Attack
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作者：Tomohiko Hinoue ; Atsuko Miyaji ; Takatomi Wada 等
期刊名称：Information and Media Technologies
电子版ISSN：1881-0896
出版年度：2007
卷号：2
期号：4
页码：1052-1061
DOI：10.11185/imt.2.1052
出版社：Information and Media Technologies Editorial Board
摘要：Knudsen and Meier applied the χ²-attack to RC6. The χ²-attack recovers a key by using high correlations measured by χ²-value. The best χ²-attacks to RC6 whose security is guaranteed theoretically works on 16-round RC6 with 192- and 256-bit key but just 8-round RC6 with 128-bit key, because it recovers keys of RC6 symmetrically, which requires a time complexity of #plaintexts × 2⁵⁴ and a memory complexity of 2⁸⁰ for recovering one key. In this paper, we improve the χ²-attack to reduce the time complexity. We give the theorem that evaluates the success probability of the χ²-attack on RC6 without using any experimental result. Our key recovery attack recovers keys asymmetrically, which requires a time complexity of #plaintexts × 2³¹ and a memory complexity of 2⁵² for recovering one key. As a result, our key recovery attack works on 16-round RC6 with 192- and 256-bit key and 12-round RC6 with 128-bit key. In the case both of 196- and 256-bit keys, our attack surprisingly reduces the time and memory complexity compared with that of the previous attack. We also demonstrate our theorem on RC6-8/4/8 and make sure of the accuracy by comparing our approximation with the experimental results.