International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Fast Correlation Attack Revisited

Yosuke Todo
Takanori Isobe
Willi Meier
Kazumaro Aoki
Bin Zhang
DOI: 10.1007/978-3-319-96881-0_5 (login may be required)
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Presentation: Slides
Conference: CRYPTO 2018
Abstract: A fast correlation attack (FCA) is a well-known cryptanalysis technique for LFSR-based stream ciphers. The correlation between the initial state of an LFSR and corresponding key stream is exploited, and the goal is to recover the initial state of the LFSR. In this paper, we revisit the FCA from a new point of view based on a finite field, and it brings a new property for the FCA when there are multiple linear approximations. Moreover, we propose a novel algorithm based on the new property, which enables us to reduce both time and data complexities. We finally apply this technique to the Grain family, which is a well-analyzed class of stream ciphers. There are three stream ciphers, Grain-128a, Grain-128, and Grain-v1 in the Grain family, and Grain-v1 is in the eSTREAM portfolio and Grain-128a is standardized by ISO/IEC. As a result, we break them all, and especially for Grain-128a, the cryptanalysis on its full version is reported for the first time.
Video from CRYPTO 2018
  title={Fast Correlation Attack Revisited},
  booktitle={Advances in Cryptology – CRYPTO 2018},
  series={Lecture Notes in Computer Science},
  author={Yosuke Todo and Takanori Isobe and Willi Meier and Kazumaro Aoki and Bin Zhang},