International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Algebraic Attacks on Summation Generators

Dong Hoon Lee
Jaeheon Kim
Jin Hong
Jae Woo Han
Dukjae Moon
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Abstract: We apply the algebraic attacks on stream ciphers with memories to the summation generator. For a summation generator that uses $n$ LFSRs, the algebraic equation relating the key stream bits and LFSR output bits can be made to be of degree less than or equal to $2^{\lceil\log_2 n \rceil}$, using $\lceil\log_2 n \rceil + 1$ consecutive key stream bits. This is much lower than the upper bound given by previous general results.
  title={Algebraic Attacks on Summation Generators},
  booktitle={IACR Eprint archive},
  keywords={stream ciphers, algebraic attacks, summation generators},
  note={ 12363 received 3 Nov 2003, last revised 6 Nov 2003},
  author={Dong Hoon Lee and Jaeheon Kim and Jin Hong and Jae Woo Han and Dukjae Moon},