The expected value of the joint linear complexity of periodic multisequences

Wilfried Meidl, Harald Niederreiter
2003 Journal of Complexity  
Complexity measures for sequences of elements of a finite field, such as the linear complexity, play an important role in cryptology. Recent developments in stream ciphers point towards an interest in word-based (or vectorized) stream ciphers, which require the study of the complexity of multisequences. We extend a well-known relationship between the linear complexity of an N-periodic sequence and the (generalized) discrete Fourier transform of Ntuples to the case of multisequences. Using the
more » ... ncept of the generalized discrete Fourier transform for multisequences, we compute the expected value of the joint linear complexity of random periodic multisequences, and for some types of period lengths N we determine the number N t N ðcÞ of t N-periodic sequences with given joint linear complexity c: r
doi:10.1016/s0885-064x(02)00009-2 fatcat:vcwrlyatc5hflgzplsv6p5ub6m