A Survey and New Results on the Decomposition of an NFSR into a Cascade Connection of Two Smaller NFSRs∗
نویسندگان
چکیده
Nonlinear feedback shift registers (NFSRs) are an important building block for stream ciphers. Given a cascade connection of two NFSRs, say NFSR(f, g), it has been known for decades how to solve the characteristic function of the NFSR which is equivalent to NFSR(f, g). However, the converse problem of decomposing an NFSR into a cascade connection of two smaller NFSRs is not completely solved, and only a special case has been studied recently. In this paper, a complete and feasible solution to the problem is given.
منابع مشابه
On Decomposition of an NFSR into a Cascade Connection of Two Smaller
Nonlinear feedback shift registers (NFSRs) are an important type of sequence generators used for building stream ciphers. The shift register used in Grain, one of eSTREAM finalists, is a cascade connection of two NFSRs, which is also known as nonlinear product-feedback shift registers proposed in 1970. This paper provides a series of algorithms to decompose a given NFSR into a cascade connectio...
متن کاملLinearization of multi-valued nonlinear feedback shift registers
The Linearization of Nonlinear feedback shift registers (NFSRs) is to find their state transition matrices. In this paper, we investigate the linearization multi-valued NFSRs by considering it as a logical network via a semi-tensor product approach. A new state transition matrix is found for an multi-valued NFSR, which can be simply computed from the truth table of its feedback function, and th...
متن کاملStability and Linearization of Multi-valued Nonlinear Feedback Shift Registers
In this paper, we study stability and linearization of multivalued nonlinear feedback shift registers which are considered as logic networks. First, the linearization of multi-valued nonlinear feedback shift registers (NFSRs) is discussed, which is to find their state transition matrices by considering it as a logical network via a semi-tensor product approach. For a multi-valued NFSR, the new ...
متن کاملNumerical Investigation on Compressible Flow Characteristics in Axial Compressors Using a Multi Block Finite Volume Scheme
An unsteady two-dimensional numerical investigation was performed on the viscous flow passing through a multi-blade cascade. A Cartesian finite-volume approach was employed and it was linked to Van-Leer's and Roe's flux splitting schemes to evaluate inviscid flux terms. To prevent the oscillatory behavior of numerical results and to increase the accuracy, Monotonic Upstream Scheme for Conservat...
متن کاملExploiting Transformations of the Galois Configuration to Improve Guess-and-Determine Attacks on NFSRs
Guess-and-determine attacks are based on guessing a subset of internal state bits and subsequently using these guesses together with the cipher’s output function to determine the value of the remaining state. These attacks have been successfully employed to break NFSRbased stream ciphers. The complexity of a guess-and-determine attack is directly related to the number of state bits used in the ...
متن کامل