Distributed key man-agement in dynamic outsourced databases: A trie-based approach

Abstract The decision to outsource databases is strategic in many organizations due to the increasing costs of internally managing large volumes of information. The sensitive nature of this information raises the need for powerful mechanisms to protect it against unauthorized disclosure. Centralized encryption to access control at the data owner level has been proposed as one way of handling this issue. However, its prohibitive costs renders it impractical and inflexible. A distributed cryptographic approach has been suggested as a promising alternative, where keys are distributed to users on the basis of their assigned privileges. But in this case, key management becomes problematic in the face of frequent database updates and remains an open issue. In this paper, we present a novel approach based on Binary Tries 1 . By exploiting the intrinsic properties of these data structures, key management complexity, and thus its cost, is significantly reduced. Changes to the Binary Trie structure remain limited in the face of frequent updates. Preliminary experimental analysis demonstrates the validity and the effectiveness of our approach

Routing and Localization Services in Self-Organizing Wireless Ad-Hoc and Sensor Networks Using Virtual Coordinates

Large scale wireless ad-hoc networks of computers, sensors, PDAs etc. (i.e. nodes) are revolutionizing connectivity and leading to a paradigm shift from centralized systems to highly distributed systems. A plethora of routing algorithms have been proposed to support path discovery into this class of networks, ranging from broadcasting/flooding approaches to global positioning systems (GPS). W-Grid is a novel infrastructure whose self-organizing routing and localization Services enable message routing and data management without reliance on flooding/broadcasting operations or GPS. The resulting ad-hoc network does not suffer from the dead-end problem, which occurs in geographic-based routing when a node is unable to locate a neighbor closer to the destination than itself. As an example of data management we present a location service that allows a device to send messages to any another node without nowing its position. Extensive performance analysis and experiments have been conducted, and the results compared to GPSR, which is considered to be the most efficient solution not using broadcast operations but exploiting nodes' position. Analysis show that the difference between the performance of our approach and GPSR is minimal and therefore very interesting, since no GPS is used

Women'S Liberation And The Moral Individualism Of Ru

May Fourth Movement is often credited with women's liberation. Yet before the word "liberation" is overused, it is necessary to talk about what is behind this fabulous word. Chapter one will mainly discuss whether women needed such liberation and whether the May Fourth Movement really helped women to be liberated. The conclusion tries to argue that the May Fourth Movement did not liberate anyone. It simply changed people's way of living; women were the focus. After May Fourth Movement, Confucianism, ru as translated here, has experienced ups and downs, and reenters Chinese people's life, as both an ancient thought and a remodeled imported study. Chapter two tries to argue that ru cannot be taken as a pure religion, or mixed up with Marxism. Moral individualism within Confucianism is a practical philosophy. To better understand moral individualism within Confucianism, the best way is to go back to Confucian classics