We construct the first Authenticated Key Exchange (AKE) protocol whose security does not degrade with an increasing number of users or sessions. We describe a three-message protocol and prove security in an enhanced version of the classical Bellare-Rogaway security model. Our construction is modular, it can be instantiated efficiently from standard assumptions (such as the SXDH or DLIN assumptions in pairingfriendly groups). For instance, we provide an SXDH-based protocol with only 14 group elements and 4 exponents communication complexity (plus some bookkeeping information). Along the way we develop new, stronger security definitions for digital signatures and key encapsulation mechanisms. For instance, we introduce a security model for digital signatures that provides existential unforgeability under chosen-message attacks in a multiuser setting with adaptive corruptions of secret keys. We show how to construct efficient schemes that satisfy the new definitions with tight security proofs under standard assumptions.
This study examines the validity of the assumption that international large-scale land acquisition (LSLA) is motivated by the desire to secure control over water resources, which is commonly referred to as ‘water grabbing’. This assumption was repeatedly expressed in recent years, ascribing the said motivation to the Gulf States in particular. However, it must be considered of hypothetical nature, as the few global studies conducted so far focused primarily on the effects of LSLA on host countries or on trade in virtual water. In this study, we analyse the effects of 475 intended or concluded land deals recorded in the Land Matrix database on the water balance in both host and investor countries. We also examine how these effects relate to water stress and how they contribute to global trade in virtual water. The analysis shows that implementation of the LSLAs in our sample would result in global water savings based on virtual water trade. At the level of individual LSLA host countries, however, water use intensity would increase, particularly in 15 sub-Saharan states. From an investor country perspective, the analysis reveals that countries often suspected of using LSLA to relieve pressure on their domestic water resources—such as China, India, and all Gulf States except Saudi Arabia—invest in agricultural activities abroad that are less water-intensive compared to their average domestic crop production. Conversely, large investor countries such as the United States, Saudi Arabia, Singapore, and Japan are disproportionately externalizing crop water consumption through their international land investments. Statistical analyses also show that host countries with abundant water resources are not per se favoured targets of LSLA. Indeed, further analysis reveals that land investments originating in water-stressed countries have only a weak tendency to target areas with a smaller water risk.
Five years after adoption of the 2030 Agenda, there is a general lack of progress in reaching its Sustainable Development Goals-be it on national, regional, or global scales. Scientists attribute this above all to insufficient understanding and addressing of interactions between goals and targets. This study aims to contribute to the methodological conceptualization of the 2030 Agenda's implementation at the national level. To this end, taking the case of Switzerland, we tested and enhanced existing approaches for assessing interactions among the 2030 Agenda's targets and for analysing the systemic relevance of priority targets. Building on our insights, the article concludes with an eight-step proposal for creating knowledge to support national 2030 Agendas.
Abstract-Instant Messaging has gained popularity by users for both private and business communication as low-cost short message replacement on mobile devices. However, until recently, most mobile messaging apps did not protect confidentiality or integrity of the messages.Press releases about mass surveillance performed by intelligence services such as NSA and GCHQ motivated many people to use alternative messaging solutions to preserve the security and privacy of their communication on the Internet. Initially fueled by Facebook's acquisition of the hugely popular mobile messaging app WHATSAPP, alternatives claiming to provide secure communication experienced a significant increase of new users.A messaging app that claims to provide secure instant messaging and has attracted a lot of attention is TEXTSECURE. Besides numerous direct installations, its protocol is part of Android's most popular aftermarket firmware CYANOGEN-MOD. TEXTSECURE's successor Signal continues to use the underlying protocol for text messaging. In this paper, we present the first complete description of TEXTSECURE's complex cryptographic protocol, provide a security analysis of its three main components (key exchange, key derivation and authenticated encryption), and discuss the main security claims of TEXTSECURE. Furthermore, we formally prove that-if key registration is assumed to be secure-TEXTSECURE's push messaging can indeed achieve most of the claimed security goals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.