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Paper 2002/005
Cryptanalysis of Stream Cipher COS (2,128) Mode I
Hongjun Wu and Feng Bao
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)
- PS
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. Unknown where it was published
- Keywords
- stream cipherscryptanalysisCOS
- Contact author(s)
- hongjun @ krdl org sg
- History
- 2002-01-04: received
- Short URL
- https://ia.cr/2002/005
- License
-
CC BY
