The need of software-flexible stream ciphers has led to several alternative proposals in the last few years. One of them is a new Pseudo Random Number Generator (PRNG), named N-adic Summation-Shrinking (NSumSG), which architecture is described in this paper. It uses N-1 parallel working slave summation generators and one N-adic summation generator, controlling the nonlinearity in the generator....

This work shows that the cryptanalysis of the shrinking generator requires fewer intercepted bits than that indicated by the linear complexity. Indeed, whereas the linear complexity of shrunken sequences is between A·2(S−2) and A·2(S−1), we claim that the initial states of both component registers are easily computed with less than A · S shrunken bits. Such a result is proven thanks to the defi...

The shrinking generator is a keystream generator which is good for stream ciphers in wireless mobile communications, because it has simple structure and generates a keystream faster than other generators. Nevertheless, it has a serious disadvantage that its keystream is not balanced if they use primitive polynomials as their feedback polynomials. In this paper, we present a method to construct ...

We provide a detailed description of solutions of Curve Shortening in Rn that are invariant under some one-parameter symmetry group of the equation, paying particular attention to geometric properties of the curves, and the asymptotic properties of their ends. We find generalized helices, and a connection with curve shortening on the unit sphere Sn−1. Expanding rotating solitons turn out to be ...

This paper presents a new type of distinguisher for the shrinking generator and the alternating-step generator with known feedback polynomial and for the multiplexor generator. For the former the distinguisher is more efficient than existing ones and for the latter it results in a complete breakdown of security. The distinguisher is conceptually very simple and lends itself to theoretical analy...

Developed, modern cities throughout the world are facing population declines at an unprecedented scale. Over the last fifty years, 370 cities throughout the world with populations over 100,000 have shrunk by at least 10% (Oswalt and Rieniets 2007). Wide swaths of the U.S., Canada, Europe, and Japan are projecting double-digit declines in population in the coming decades. Internationally, schola...

In this paper, we classify the four-dimensional gradient shrinking solitons under certain curvature conditions satisfied by all solitons arising from finite-time singularities of Ricci flow on compact four-manifolds with positive isotropic curvature. As a corollary, we generalize a result of Perelman on three-dimensional gradient shrinking solitons to dimension four.

Sequence compression is one of the most promising tools for strengthening pseudo-random generators used in stream ciphers. Indeed, adding compression components can thwart algebraic attacks aimed at LFSR-based stream ciphers. Among such components are the Shrinking Generator and the Self-Shrinking Generator, as well as recent variations on Bit-Search-based decimation. We propose a general model...