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Impossible differential cryptanalysis of reduced-round TEA and XTEA

Hajari, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1109/ISCISC.2015.7387899
  3. Publisher: Institute of Electrical and Electronics Engineers Inc
  4. Abstract:
  5. TEA and XTEA are two lightweight Feistel block ciphers, each of which has a block size of 64 bits and a key size of 128 bits. These two ciphers have ARX structure, i.e. their round functions consist of modular addition, shift and XOR to be exact. Since each operation of TEA and XTEA can be done in a bitwise fashion, we are able to use early abort technique in the impossible differential attack that helps us to remove inappropriate pairs as soon as possible, hence decreasing time complexity. In this paper we present two new 15-round impossible differential characteristics, resulting in the first known impossible differential cryptanalysis mounted on 19 rounds of TEA and 25 rounds of XTEA
  6. Keywords:
  7. Block Cipher ; Impossible Differential Cryptanalysis ; Lightweight ; TEA ; XTEA ; Lyapunov methods ; Security of data ; Differential attacks ; Differential characteristic ; Modular addition ; Time complexity ; Cryptography
  8. Source: 12th International ISC Conference on Information Security and Cryptology, 8 September 2015 through 10 September 2015 ; 2015 , Pages 58-63 ; 9781467376099 (ISBN)
  9. URL: http://ieeexplore.ieee.org/document/7387899