State convergence in the initialisation of stream ciphers

An initialisation process is a key component in modern stream cipher design. A well-designed initialisation process should ensure that each key-IV pair generates a different key stream. In this paper, we analyse two ciphers, A5/1 and Mixer, for which this does not happen due to state convergence. We show how the state convergence problem occurs and estimate the effective key-space in each case.

Unbiased estimation of the half-life to price index convergence among U.S. cities

Estimates of the half-life to convergence of prices across a panel of cities are subject to bias from three potential sources: inappropriate cross-sectional aggregation of heterogeneous coefficients, presence of lagged dependent variables in a model with individual fixed effects, and time aggregation of commodity prices. This paper finds no evidence of heterogeneity bias in annual CPI data for 17 U.S. cities from 1918 to 2006, but correcting for the “Nickell bias” and time aggregation bias produces a half-life of 7.5 years, shorter than estimates from previous studies.

A human capital framework : designed for convergence

The 21" century business environment is dominated by unprecedented change across a broad spectrum of social, economic, technological and cultural factors (Nowotny, Scott & Gibbons 2001). Among these, two broad trends -economic globalisation and rising knowledge intensity (Hart 2006)have come to distinguish organisational life. Under the weight of these transformational influences, the developed world, it seems, has arrived at a transformational moment. The far-reaching effects of the global financial crisis and its shadowy twin: the threat of a double dip recession, continue to exert an unsteadying influence on global and corporate finances. Growth in developed economies has slumped, share prices have declined, the market value of corporations has slipped and unemployment rates, in the vast majority of developed economies, have risen. Gross domestic product (GDP) growth has retreated from the strong growth experienced in the late 1990s to negative growth in 2009 and a sluggish and unsteady recovery in 2010. In response, the reach of Government in terms of its participation in markets has been extended, bringing with it the need to transition to new governance and regulatory arrangements. Ongoing concerns regarding the pace and sustainability of the recovery remains a front-of-mind concern with bailouts, buybacks, borrowings and BP dominating news services: 'We are witnessing the reweaving of the social, political and economic fabric that binds our planet, with long-term consequences that are as or more profound than those of the industrial era' (Tapscott & Williams 2006, p. 59).

State convergence and the effectiveness of time-memory-data tradeoffs

Various time-memory tradeoffs attacks for stream ciphers have been proposed over the years. However, the claimed success of these attacks assumes the initialisation process of the stream cipher is one-to-one. Some stream cipher proposals do not have a one-to-one initialisation process. In this paper, we examine the impact of this on the success of time-memory-data tradeoff attacks. Under the circumstances, some attacks are more successful than previously claimed while others are less. The conditions for both cases are established.

Points of convergence and divergence : normative, institutional and operational relationships between R2P and POC

As an international norm, the Responsibility to Protect (R2P) has gained substantial influence and institutional presence—and created no small controversy—in the ten years since its first conceptualisation. Conversely, the Protection of Civilians in Armed Conflict (PoC) has a longer pedigree and enjoys a less contested reputation. Yet UN Security Council action in Libya in 2011 has thrown into sharp relief the relationship between the two. UN Security Council Resolutions 1970 and 1973 follow exactly the process envisaged by R2P in response to imminent atrocity crimes, yet the operative paragraphs of the resolutions themselves invoke only PoC. This article argues that, while the agendas of PoC and R2P converge with respect to Security Council action in cases like Libya, outside this narrow context it is important to keep the two norms distinct. Peacekeepers, humanitarian actors, international lawyers, individual states and regional organisations are required to act differently with respect to the separate agendas and contexts covered by R2P and PoC. While overlap between the two does occur in highly visible cases like Libya, neither R2P nor PoC collapses normatively, institutionally or operationally into the other.

State convergence in the initialisation of the Sfinks stream cipher

Sfinks is a shift register based stream cipher designed for hardware implementation. The initialisation state update function is different from the state update function used for keystream generation. We demonstrate state convergence during the initialisation process, even though the individual components used in the initialisation are one-to-one. However, the combination of these components is not one-to-one.

Australian content and convergence

This article is a response to Kim Dalton's 2011 Henry Mayer Lecture. It focuses on Dalton's discussion of Australian content in the context of the government's ongoing Convergence Review.

State convergence and keyspace reduction of the mixer stream cipher

This paper presents an analysis of the stream cipher Mixer, a bit-based cipher with structural components similar to the well-known Grain cipher and the LILI family of keystream generators. Mixer uses a 128-bit key and 64-bit IV to initialise a 217-bit internal state. The analysis is focused on the initialisation function of Mixer and shows that there exist multiple key-IV pairs which, after initialisation, produce the same initial state, and consequently will generate the same keystream. Furthermore, if the number of iterations of the state update function performed during initialisation is increased, then the number of distinct initial states that can be obtained decreases. It is also shown that there exist some distinct initial states which produce the same keystream, resulting in a further reduction of the effective key space

Stability and convergence of implicit numerical methods for a class of fractional advection-dispersion models

In this paper, a class of fractional advection-dispersion models (FADM) is investigated. These models include five fractional advection-dispersion models: the immobile, mobile/immobile time FADM with a temporal fractional derivative 0 < γ < 1, the space FADM with skewness, both the time and space FADM and the time fractional advection-diffusion-wave model with damping with index 1 < γ < 2. They describe nonlocal dependence on either time or space, or both, to explain the development of anomalous dispersion. These equations can be used to simulate regional-scale anomalous dispersion with heavy tails, for example, the solute transport in watershed catchments and rivers. We propose computationally effective implicit numerical methods for these FADM. The stability and convergence of the implicit numerical methods are analyzed and compared systematically. Finally, some results are given to demonstrate the effectiveness of our theoretical analysis.

Convergence and Australian content : the importance of access

In the light of new and complex challenges to media policy and regulation, the Austrlaian government commissioned the Convergence Review in late 2010 to assess the continuing applicability and utility of the principles and objectives that have shaped the policy framework to this point. It proposed a range of options for policy change and identified three enduring priorities for continued media regulation: media ownership and control; content standards; and Australian content production and distribution. The purpose of this article is to highlight an area where we feel there are opportunities for further discussion and research: the question of how the accessibility and visibility of Australian and local content may be assured in the future media policy framework via a combination of regulation and incentives to encourage innovation in content distribution.

The Convergence Review and the future of Australian content regulation

This article examines the place of Australian and local content regulation in the new media policy framework proposed by the Convergence Review. It outlines the history of Australian content regulation and the existing policy framework, before going on to detail some of the debates around Australian content during the Review. The final section analyses the relevant recommendations in the Convergence Review Final Report, and highlights some issues and problems that may arise in the new framework.

Stability and convergence of a finite volume method for the space fractional advection-dispersion equation

We consider the space fractional advection–dispersion equation, which is obtained from the classical advection–diffusion equation by replacing the spatial derivatives with a generalised derivative of fractional order. We derive a finite volume method that utilises fractionally-shifted Grünwald formulae for the discretisation of the fractional derivative, to numerically solve the equation on a finite domain with homogeneous Dirichlet boundary conditions. We prove that the method is stable and convergent when coupled with an implicit timestepping strategy. Results of numerical experiments are presented that support the theoretical analysis.

State convergence in bit-based stream ciphers

Well-designed initialisation and keystream generation processes for stream ciphers should ensure that each key-IV pair generates a distinct keystream. In this paper, we analyse some ciphers where this does not happen due to state convergence occurring either during initialisation, keystream generation or both. We show how state convergence occurs in each case and identify two mechanisms which can cause state convergence.