When Lagged Fibonacci Generators jump

Autor: Moon K. Chetry, Vashek Matyas, Susil Kumar Bishoi
Rok vydání: 2019
Předmět:
Zdroj: Discrete Applied Mathematics. 267:64-72
ISSN: 0166-218X
DOI: 10.1016/j.dam.2019.06.022
Popis: Jansen introduced a primitive called jumped Linear Feedback Shift Register (LFSR) for building LFSRs that can be clocked a large number of times with a single simple operation. This is useful in the construction of stream ciphers based on clock-controlled LFSRs. A concept of Lagged Fibonacci Generator (LFG) is also used as an important building block of key-stream generators in stream cipher cryptography. In this paper, we use the jumping concept of Jansen in case of LFG. We show that unlike LFSRs, LFGs need not jump always in the state space itself, even though the characteristic polynomial is primitive. Instead, it may have a hyper space jump depending on the characteristic primitive polynomial. We give a necessary and sufficient condition for an LFG to jump within the state space itself and when it exists, it is same as the degree of the characteristic polynomial.
Databáze: OpenAIRE