Journal of South China University of Technology (Natural Science Edition) ›› 2007, Vol. 35 ›› Issue (5): 86-89.

• Computer Science & Technology • Previous Articles     Next Articles

Periodic Sequences with Large 2-adic and κ-error 2-adic Complexities

Dong Li-Hua  Hu Yu-pu  Zeng Yong   

  1. Key Laboratory of Computer Networks and Information Security of the Ministrγof Education ,Xidian Univ. , Xi' an 710071 , Shaanxi , China
  • Received:2005-12-05 Online:2007-05-25 Published:2007-05-25
  • Contact: 董丽华(1977-)，女，博士，主要从事流密码体制的设计与安全性分析方面的研究. E-mail:lih_dong@hotmail.com
  • About author:董丽华(1977-)，女，博士，主要从事流密码体制的设计与安全性分析方面的研究.
  • Supported by:

    国家自然科学基金资助项目(60473029 ，60673072)

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Abstract:

According to the theory of stream ciphers in cryptology , the 2-adic complexity and. the κ-error 2-adic complexity similar to other complexity measures must have large values. In this paper , the relationship between the linear complexity and the 2-adic complexity is investigated based on the Chinese Remainder Theorem and some other related theories in the number theory , and the existence of N-periodic sequences that simultaneously achieve the maximum 2-adic complexity and a great κ-error 2-adic complexity is proved. Then , a lower bound of the number of the N-periodic sequences with such properties is given. The existence of many such sequences can effectively thwart the attacks against the keystreams by exhaustive search.

Key words: information security, cryptography, 2-adic complexity, κ-error 2-adic complexity, periodic sequence