IMS signalling for multiparty services based on network level multicast

3rd EURO-NGI Conference on Next Generation Internet Networks. Norwegian University of Science and Technology, Trondheim, Norway, 21-23 may 2007.The standardization process of the UMTS technology has led to the development of the IP Multimedia Subsystem (IMS). IMS provides a framework that supports the negotiation of the next generation multimedia services with QoS requirements that are envisioned for 3G networks. But even though many of these services involve the participation of multiple users in a multiparty arrangement, the delivery technology at network level is still unicast based. This approach is not optimum, in terms of transmission efficiency. In this paper, a new approach is presented proposing to use a network level multicast delivery technology for the multiparty services that are signalled through IMS. The main advantages and drawbacks related with this new approach are analyzed in the article. Finally, as a starting point in the development of the presented solution, a new SIP signalling dialogue is proposed allowing the negotiation of a generic multiparty service, and supporting at the same time the configuration of the corresponding network level multicast delivery service with QoS requirements that will be used in the user plane.Publicad

ARPA Whitepaper

We propose a secure computation solution for blockchain networks. The correctness of computation is verifiable even under malicious majority condition using information-theoretic Message Authentication Code (MAC), and the privacy is preserved using Secret-Sharing. With state-of-the-art multiparty computation protocol and a layer2 solution, our privacy-preserving computation guarantees data security on blockchain, cryptographically, while reducing the heavy-lifting computation job to a few nodes. This breakthrough has several implications on the future of decentralized networks. First, secure computation can be used to support Private Smart Contracts, where consensus is reached without exposing the information in the public contract. Second, it enables data to be shared and used in trustless network, without disclosing the raw data during data-at-use, where data ownership and data usage is safely separated. Last but not least, computation and verification processes are separated, which can be perceived as computational sharding, this effectively makes the transaction processing speed linear to the number of participating nodes. Our objective is to deploy our secure computation network as an layer2 solution to any blockchain system. Smart Contracts\cite{smartcontract} will be used as bridge to link the blockchain and computation networks. Additionally, they will be used as verifier to ensure that outsourced computation is completed correctly. In order to achieve this, we first develop a general MPC network with advanced features, such as: 1) Secure Computation, 2) Off-chain Computation, 3) Verifiable Computation, and 4)Support dApps' needs like privacy-preserving data exchange

Multiparty talk in the novel: the distribution of tea and talk in a scene from Evelyn Waugh's Black Mischief

This article argues that studies of fictional dialogue have hitherto neglected the specific dynamics of multiparty talk. I will contend that this neglect contributes to the perpetuation of an "ideal" of conversation that allows no space for either the frustrations and inequalities of such encounters or the unique pleasures they may bring to the reader. I urge the importance of distinguishing between group talk, in which there is some element of cohesion and shared goals, and multiparty talk, in which the representation foregrounds fragmentation and explores the often subtle power games played by the participants. Focusing on a scene from Evelyn Waugh's Black Mischief (1986 [1932]), I argue that Waugh is sensitive to the dynamics of multiparty talk while orchestrating the representation for comic effect. I propose that analyzing such scenes of multiparty talk must make us reassess not only how we theorize fictional dialogue, but how far our models of everyday speech serve to privilege and universalize certain conversational practices and mechanisms based almost exclusively on the duologue

Experimental demonstration of four-party quantum secret sharing

Secret sharing is a multiparty cryptographic task in which some secret information is splitted into several pieces which are distributed among the participants such that only an authorized set of participants can reconstruct the original secret. Similar to quantum key distribution, in quantum secret sharing, the secrecy of the shared information relies not on computational assumptions, but on laws of quantum physics. Here, we present an experimental demonstration of four-party quantum secret sharing via the resource of four-photon entanglement

Democracy and Education Spending: Has Africas Move to Multiparty Elections Made a Difference to Policy?

While it is generally recognized that electoral competition can have a major influence on public spending decisions, there has been little effort to consider whether the move to multiparty elections in African countries in recent years has led to a redistribution of public expenditures between social groups. In this paper I develop a hypothesis, illustrated with a simple game-theoretic model, which suggests that the need to obtain an electoral majority may have prompted African governments to devote greater resources to primary schools. I test this proposition using panel data on electoral competition and education spending in thirty-five African countries over the period 1981-1996. The results show that democratization has indeed been associated with greater spending on primary schools, and these findings are robust to controls for unobserved country effects. They are also supported by evidence from recent country cases. Though the reemergence of multiparty democracy in Africa has not led to a wholesale transformation of economic policies, these findings nonetheless suggest that it may be having a significant impact in individual policy areas.Primary education, political economy, democracy, electoral competition.

Combining behavioural types with security analysis

Today's software systems are highly distributed and interconnected, and they increasingly rely on communication to achieve their goals; due to their societal importance, security and trustworthiness are crucial aspects for the correctness of these systems. Behavioural types, which extend data types by describing also the structured behaviour of programs, are a widely studied approach to the enforcement of correctness properties in communicating systems. This paper offers a unified overview of proposals based on behavioural types which are aimed at the analysis of security properties

The Crypto-democracy and the Trustworthy

In the current architecture of the Internet, there is a strong asymmetry in terms of power between the entities that gather and process personal data (e.g., major Internet companies, telecom operators, cloud providers, ...) and the individuals from which this personal data is issued. In particular, individuals have no choice but to blindly trust that these entities will respect their privacy and protect their personal data. In this position paper, we address this issue by proposing an utopian crypto-democracy model based on existing scientific achievements from the field of cryptography. More precisely, our main objective is to show that cryptographic primitives, including in particular secure multiparty computation, offer a practical solution to protect privacy while minimizing the trust assumptions. In the crypto-democracy envisioned, individuals do not have to trust a single physical entity with their personal data but rather their data is distributed among several institutions. Together these institutions form a virtual entity called the Trustworthy that is responsible for the storage of this data but which can also compute on it (provided first that all the institutions agree on this). Finally, we also propose a realistic proof-of-concept of the Trustworthy, in which the roles of institutions are played by universities. This proof-of-concept would have an important impact in demonstrating the possibilities offered by the crypto-democracy paradigm.Comment: DPM 201