title: On the insecurity of arithmetic coding

authors: Cleary, John G.

subjects: computer science

abstract: Arithmetic coding is a technique which converts a given probability distribution into an optimal code and is commonly used in compression schemes. The use of arithmetic coding as an encryption scheme is considered. The simple case of a single binary probability distribution with a fixed (but unknown) probability is considered. We show that for a chosen plaintext attack w+ 2 characters is sufficient to uniquely determine a w-bit probability. For many known plaintexts w+ m+ O(log m) symbols where mis the length of an initial sequence containing just one of (the two possible) symbols is sufficient. It is noted that many extensions to this basic scheme are vulnerable to the same attack provided the arithmetic coder can be repeatedly reset to its initial state. If it cannot be reset then their vulnerability remains an open question.

text: On the insecurity of arithmetic coding Arithmetic coding is a technique which converts a given probability distribution into an optimal code and is commonly used in compression schemes. The use of arithmetic coding as an encryption scheme is considered. The simple case of a single binary probability distribution with a fixed (but unknown) probability is considered. We show that for a chosen plaintext attack w+ 2 characters is sufficient to uniquely determine a w-bit probability. For many known plaintexts w+ m+ O(log m) symbols where mis the length of an initial sequence containing just one of (the two possible) symbols is sufficient. It is noted that many extensions to this basic scheme are vulnerable to the same attack provided the arithmetic coder can be repeatedly reset to its initial state. If it cannot be reset then their vulnerability remains an open question.

year: 1994-06

title: The energy cultures framework: Exploring the role of norms, practices and material culture in shaping energy behaviour in New Zealand

authors: Stephenson, Janet

subjects: Energy behaviour

abstract: The energy cultures framework was developed in 2009 to support interdisciplinary investigation into energy behaviour in New Zealand. In this paper, we discuss the framework in light of 5 years of empirical application and conceptual development. The concept of culture is helpful in seeking to better understand energy behaviour because it conveys how behaviours are embedded within the physical and social contexts of everyday life, and how they are both repetitive and heterogeneous. The framework suggests that the energy culture of a given subject (e.g. an individual, a household, a business, a sector) can be studied by examining the interrelationships between their norms, practices and material culture, and how these, in turn, are shaped by external influences. We discuss the key theoretical influences of the framework, and how the core concepts of the framework have evolved as we have applied them in different research situations. We then illustrate how we have applied the framework to a range of topics and sectors, and how it has been used to support interdisciplinary research, in identifying clusters of energy cultures, in examining energy cultures at different scales and in different sectors, and to inform policy development.

text: The energy cultures framework: Exploring the role of norms, practices and material culture in shaping energy behaviour in New Zealand The energy cultures framework was developed in 2009 to support interdisciplinary investigation into energy behaviour in New Zealand. In this paper, we discuss the framework in light of 5 years of empirical application and conceptual development. The concept of culture is helpful in seeking to better understand energy behaviour because it conveys how behaviours are embedded within the physical and social contexts of everyday life, and how they are both repetitive and heterogeneous. The framework suggests that the energy culture of a given subject (e.g. an individual, a household, a business, a sector) can be studied by examining the interrelationships between their norms, practices and material culture, and how these, in turn, are shaped by external influences. We discuss the key theoretical influences of the framework, and how the core concepts of the framework have evolved as we have applied them in different research situations. We then illustrate how we have applied the framework to a range of topics and sectors, and how it has been used to support interdisciplinary research, in identifying clusters of energy cultures, in examining energy cultures at different scales and in different sectors, and to inform policy development.

year: 2015

title: Challenges to psychology in Aotearoa

authors: Awatere-Huata, Donna

subjects: Maori

abstract: Maori people are putting up with a lot right now. If governments can transfer $20 billion in the past ten years for hand outs and write offs to Pakeha people who have endured little, then they can do a lot better than the $150 million they’ve transferred to our people that have endured so much for 150 years.  The big issue is still the Treaty, and the need to re-negotiate this nation’s management. The challenge is to design a political system that is based on Maori ways of doing things rather than Pakeha ways of doing things. To achieve this requires relinquishing colonial patterns of thinking and the certainty that pakeha people and their ways are superior to Maori. For psychologists the issue is their role in maintaining Pakeha economic and political power. It may well be that psychologists provide lousy value for money from the Maori point of view, but provide excellent value for money from the government’s point of view.

text: Challenges to psychology in Aotearoa Maori people are putting up with a lot right now. If governments can transfer $20 billion in the past ten years for hand outs and write offs to Pakeha people who have endured little, then they can do a lot better than the $150 million they’ve transferred to our people that have endured so much for 150 years.  The big issue is still the Treaty, and the need to re-negotiate this nation’s management. The challenge is to design a political system that is based on Maori ways of doing things rather than Pakeha ways of doing things. To achieve this requires relinquishing colonial patterns of thinking and the certainty that pakeha people and their ways are superior to Maori. For psychologists the issue is their role in maintaining Pakeha economic and political power. It may well be that psychologists provide lousy value for money from the Maori point of view, but provide excellent value for money from the government’s point of view.

year: 1993