Substantial research has been devoted to the modelling of the small-world phenomenon that arises in nature as well as human society. Earlier work has focused on the static properties of various small-world models. To ...
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Substantial research has been devoted to the modelling of the small-world phenomenon that arises in nature as well as human society. Earlier work has focused on the static properties of various small-world models. To examine the routing aspects, Kleinberg proposes a model based on a d-dimensional toroidal lattice with long-range links chosen at random according to the d-harmonic distribution. Kleinberg shows that, by using only local information, the greedy routing algorithm performs in O(lg^2 n) expected number of hops. We extend Kleinberg's small-world model by allowing each node x to have two more random links to nodes chosen uniformly and randomly within (lg n)2/d Manhattan distance from x. Based on this extended model, we then propose an oblivious algorithm that can route messages between any two nodes in O(lg n) expected number of hops. Our routing algorithm keeps only O((lgn)β+1) bits of information on each node, where 1 〈 β 〈 2, thus being scalable w.r.t, the network size. To our knowledge, our result is the first to achieve the optimal routing complexity while still keeping a poly-logarithmic number of bits of information stored on each node in the small-world networks.
Nowadays, the vast majority of Internet services used to distribute hypermedia content follow a centralized model, which is highly dependent on servers and raises several quality and security concerns. Among other iss...
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Nowadays, the vast majority of Internet services used to distribute hypermedia content follow a centralized model, which is highly dependent on servers and raises several quality and security concerns. Among other issues, this centralized model creates single points of failure, requires trust on providers to avoid censorship and personal data misuse, and results in a scenario where digital content tends to disappear or be inaccessible over time, for example, when a content creator stops maintaining a site or when the content is moved to another location. To improve this, it is necessary to replicate data and follow more distributed models. Nevertheless, current platforms to distribute content in this way, either do not offer an effective mechanism to maintain the privacy of their users or they offer full-anonymity, which contributes to the dissemination of content that goes beyond the law and moral standards of many users. This paper proposes a novel distributed architecture that enables hypermedia resource distribution ensuring censorship resistance and conditional k-anonymity. In the proposed system, users form groups to share hypermedia content where the anonymity of the publisher is preserved only if the publication follows a set of rules defined by the group. To this end, the proposed system uses threshold discernible ring signatures to enable conditional k-anonymity, the Ethereum blockchain platform to manage groups and user identities, and the InterPlanetary File System to store and share hypermedia resources in a distributed way. This document provides the design for the proposed architecture and protocols, it evaluates system risks and its security properties, and it discusses the proposal in general terms.
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