Improved automatic search of impossible differentials for camellia with FL/FL −1 layers

Automatic Search of Truncated Impossible Differentials and Applications

Finding the longest impossible differentials is an essential assignment in proceeding impossible differential cryptanalysis. In this paper, we introduce a novel tool to search the longest truncated impossible differentials for word-oriented block ciphers with bijective S-boxes. It costs polynomial time to return a flag indicating whether a truncated differential is impossible under several filt...

Automatic Search of Truncated Impossible Differentials for Word-Oriented Block Ciphers

Automatic Search of Truncated Impossible Differentials for Word-Oriented Block Ciphers (Full Version)

Impossible differential cryptanalysis is a powerful technique to recover the secret key of block ciphers by exploiting the fact that in block ciphers specific input and output differences are not compatible. This paper introduces a novel tool to search truncated impossible differentials for word-oriented block ciphers with bijective Sboxes. Our tool generalizes the earlier U-method and the UID-...

New Automatic Search Tool for Impossible Differentials and Zero-Correlation Linear Approximations

Impossible differential cryptanalysis and zero-correlation linear cryptanalysis are two of the most useful cryptanalysis methods in the field of symmetric ciphers. Until now, there are several automatic search tools for impossible differentials such as U-method and UID-method, which are all independent of the non-linear S-boxes. Since the differential and linear properties can also contribute t...

Impossible Differential Cryptanalysis of ARIA and Camellia

This paper studies the security of the block ciphers ARIA and Camellia against impossible differential cryptanalysis. Our work improves the best impossible differential cryptanalysis of ARIA and Camellia known so far. The designers of ARIA expected no impossible differentials exist for 4-round ARIA. However, we found some nontrivial 4-round impossible differentials, which may lead to a possible...