New method creates complex multi-sequences for better cryptography

Construction of Multi-sequences With High Nonlinear Complexity via Narrow Ray Class Fields

Information Theory

Summary

Generating sequences that are hard to predict is very important for keeping information secure. The authors build on earlier work to create a flexible method for making multiple such sequences that are very complex in a nonlinear way. They use advanced math called narrow ray class fields to do this, which lets them create these sequences over different kinds of function fields. This approach can help improve cryptographic systems by providing stronger pseudorandom sequences.

What this means in practice

Authors

Xiaofeng Liu, Jun Zhang, Fang-Wei Fu

Abstract

Nonlinear complexity is a fundamental criterion in the evaluation of pseudorandom sequences. The construction of multi-sequences with high nonlinear complexity is both theoretically and practically important in cryptography. Motivated by prior constructions of multi-sequences with high nonlinear complexity in [IEEE Trans. Inf. Theory, 60(10), 2014] and [IEEE Trans. Inf. Theory, 63(12), 2017], we provide a unified framework via narrow ray class fields, the cyclic descent due to Guruswami and Xing in [J. Combin. Theory Ser. A 129 (2015) ]. Then we can generate new multi-sequences with high nonlinear complexity over function fields with arbitrary genera.