Welcome to the resource topic for 2021/829
Title:
To Shift or Not to Shift: Understanding GEA-1
Authors: Christof Beierle, Patrick Felke, Gregor Leander
Abstract:In their Eurocrypt 2021 paper, Beierle et al. showed that the proprietary stream ciphers GEA-1 and GEA-2, widely used for GPRS encryption in the late 1990s and during the 2000s, are cryptographically weak and presented attacks on both algorithms with practical time complexity. Although GEA-1 and GEA-2 are classical stream ciphers, the attack on GEA-1 is interesting from a cryptanalytic point of view. As outlined in the aforementioned paper, there is a strong indication that the security of GEA-1 was deliberately weakened to 40 bits in order to fulfill European export restrictions. In this paper we analyze the design further and answer the open question on how to construct a GEA-1-like cipher with such a reduced security. Indeed, the actual GEA-1 instance could be obtained from this construction. Our observations and analysis yields new theoretical insights in designing secure stream ciphers.
ePrint: https://eprint.iacr.org/2021/829
Talk: https://www.youtube.com/watch?v=WMaV4pK1spA
Slides: https://iacr.org/submit/files/slides/2022/crypto/crypto2022/255/slides.pdf
See all topics related to this paper.
Feel free to post resources that are related to this paper below.
Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.
For more information, see the rules for Resource Topics .