(1057, 31)-Aralıklı Dizilerden Üretilen Boole Fonksiyonlar

Öz

1983 yılında keşfedildikten itibaren günümüzde halen bilinen en yüksek doğrusal olmama değerine (16276) sahip olan 15-değişkenli Patterson-Wiedemann (PW) fonksiyonlarının, özel bir yapıda bulunan (151, 217)-aralıklı dizilerden üretilen döngüsel simetrik Boole fonksiyonları (DSBF’ler) olarak yorumlanabildiği bilinmektedir. İlgili literatürde, aynı doğrusal olmama değerine ulaşan başka bir inşa/arama yöntemi bilinmemekle birlikte, tam arama veya sezgisel arama yöntemleri ile (151, 217)- ve (217, 151)-aralıklı dizilerden, bükük-bağlaşım sınırını (16256) aşan doğrusal olmama değerine sahip genelleştirilmiş DSBF’lerin elde edilebildiği gösterilmiştir. Ancak, bahsedilen yöntemlerle ulaşılan en iyi doğrusal olmama değeri 16268’i aşamamıştır. Bu çalışmamızda, bildiğimiz kadarıyla ilk defa (1057, 31)-aralıklı dizilerden üretilen DSBF’ler araştırılmış ve sezgisel arama yöntemi ile 16272 doğrusal olmama değerine ulaşılmıştır.

Anahtar Kelimeler

• Aralıklı dizi
• bükük-bağlaşım sınırı
• döngüsel simetrik Boole fonksiyonu (DSBF)
• doğrusal olmama

Boolean Functions Generated from (1057, 31)-Interleaved Sequences

Öz

It is known that Patterson-Wiedemann (PW) functions with 15-variables, which still have the highest known nonlinearity value (16276) since their discovery in 1983, can be interpreted as rotation-symmetric Boolean functions (RSBFs) produced from (151, 217)-interleaved sequences which are in the form of a special structure. In the related literature, though no other search/construction method achieving the same nonlinearity value is known, it has been shown that generalized RSBFs with nonlinearity exceeding the bent-concatenation bound (16256) can be obtained from (151, 217)- and (217, 151)-interleaved sequences by using exhaustive or heuristic search methods. However, the best nonlinearity value reached by these methods could not exceed 16268. In this study, RSBFs produced from (1057, 31)-interleaved sequences are investigated for the first time to the best of our knowledge, and the nonlinearity value of 16272 is attained by a heuristic search method.

Anahtar Kelimeler

• Bent-concatenation bound
• interleaved sequence
• nonlinearity
• rotation-symmetric Boolean function (RSBF)

Kaynakça

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