an improved time-memory-data trade-off attack against irregularly clocked and filtered keystream generators

ISCAS OpenIR

	an improved time-memory-data trade-off attack against irregularly clocked and filtered keystream generators
	Jiao Lin; Wang Mingsheng; Zhang Bin; Li Yongqiang
	2013
会议名称	8th China International Conference on Information Security and Cryptology, INSCRYPT 2012
会议录名称	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
页码	294-310
会议日期	November 28, 2012 - November 30, 2012
会议地点	Beijing, China
收录类别	EI
ISSN	0302-9743
ISBN	9783642385186
部门归属	(1) Institute of Software Chinese Academy of Sciences Beijing 100190 China; (2) Graduate University of Chinese Academy of Sciences Beijing 100049 China; (3) State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences Beijing 100093 China
摘要	In this paper, we propose a new key recovery attack against irregularly clocked keystream generators, using the approach of time-memory-data trade-offs. The main idea behind our attack is creating several look-up tables and finally recovering the initial states of LFSR d and LFSR c synchronously, by alternatively deriving the initial states of LFSR d and LFSR c along the chains. We show that our attack is more efficient, and improves the previous attacks on the cipher model. Especially, we prove that our attack almost always needs less complexity than that of the normal time-memory-data trade-off attack [3] on the cipher model. We test our attack on LILI-128, and find out that it can successfully break the cipher with 2^56.6 bit-comparison operations, 2⁴⁹ pairs of 89-bit words memory and 2⁵⁹ keystream bits. This result is better than those in [15,6], which possess the complexity of 2⁶² parity checks and 2 ⁶³ bit operations respectively. Moreover, our attack can be divided and computed in parallel, and the actual runtime of the attack can be reduced depending on the number of computers we access. © 2013 Springer-Verlag Berlin Heidelberg.; In this paper, we propose a new key recovery attack against irregularly clocked keystream generators, using the approach of time-memory-data trade-offs. The main idea behind our attack is creating several look-up tables and finally recovering the initial states of LFSR d and LFSR c synchronously, by alternatively deriving the initial states of LFSR d and LFSR c along the chains. We show that our attack is more efficient, and improves the previous attacks on the cipher model. Especially, we prove that our attack almost always needs less complexity than that of the normal time-memory-data trade-off attack [3] on the cipher model. We test our attack on LILI-128, and find out that it can successfully break the cipher with 2^56.6 bit-comparison operations, 2⁴⁹ pairs of 89-bit words memory and 2⁵⁹ keystream bits. This result is better than those in [15,6], which possess the complexity of 2⁶² parity checks and 2 ⁶³ bit operations respectively. Moreover, our attack can be divided and computed in parallel, and the actual runtime of the attack can be reduced depending on the number of computers we access. © 2013 Springer-Verlag Berlin Heidelberg.
关键词	Clocks Cryptography Security Of Data Shift Registers Table Lookup
语种	英语
内容类型	会议论文
URI标识	http://ir.iscas.ac.cn/handle/311060/15977
专题	中国科学院软件研究所
推荐引用方式 GB/T 7714	Jiao Lin,Wang Mingsheng,Zhang Bin,et al. an improved time-memory-data trade-off attack against irregularly clocked and filtered keystream generators[C],2013:294-310.