Paper 2002/005 Original: eprint.iacr.org/2002/005 ↗
Cryptanalysis of Stream Cipher COS (2,128) Mode I
Abstract
Filiol and Fontaine recently proposed a family of stream ciphers named COS. COS is based on nonlinear feedback shift registers and was claimed to be with high cryptographic strength. Babbage showed that COS $(2,128)$ Mode II is extremely weak. But Babbage's attack is too expensive to break the COS $(2,128)$ Mode I (the complexity is around $2^{52}$). In this paper, we show that the COS $(2,128)$ Mode I is too weak. With about $2^{16}$-bit known plaintext, the secret information could be recovered with small amount of memory and computation time (less than one second on a Pentium IV Processor).
Metadata
- Available format(s)
PDF- Category
- Secret-key cryptography
- Publication info
- Preprint.
- History
- 2002-01-04: last updated
- 2002-01-04: published
- Short URL
- https://ia.cr/2002/005
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2002/005,
author = {Hongjun Wu and Feng Bao},
title = {Cryptanalysis of Stream Cipher COS (2,128) Mode I},
howpublished = {Cryptology {ePrint} Archive, Paper 2002/005},
year = {2002},
url = {https://eprint.iacr.org/2002/005}
}