Mobile users share the same expectations as wired users: they want to communicate with other people, they ex-pect the communication to be secure, and it should all be easy. However, mobility poses many challenges for security. Communication is often ad hoc, and the infras-tructure may be untrusted. Secure communication relies on the distribution of au-thentic information among the communicating parties’ devices. This is a challenging problem because devices generally do not share pre-existing secrets. Current secu-rity protocols for distributing initial authentic informa-tion fail to consider the human element. Many protocols do not scale beyond a pair of devices, although people often need to communicate with a group. The few exist-ing group protocols assume that users will always count the number of members and verify the list of members correctly. However, as group size increases, implemen-tations of these protocols become more prone to human error. We present GAnGS, a fully-implemented system for exchanging authentic information between mobile de-vices when they are physically present in the same lo-cation. GAnGS is scalable, appropriate for two or more devices. We implement two user-friendly variants of GAnGS on Nokia N70 camera phones. The first vari-ant, GAnGS-P, is based on an untrusted communication hub. The second variant, GAnGS-T, needs no infrastruc-ture. Both variants use Bluetooth for peer-to-peer wire-less communication during the information exchange. 1

Establishing secure communication among a group of physically collocated people is a challenge. This problem can be reduced to establishing authentic public keys among all the participants – these public keys then serve to establish a shared secret symmetric key for encryption and authentication of messages. Unfortunately, in most real-world settings, public key infrastructures (PKI) are uncommon and distributing a secret in a public space is difficult. Thus, it is a challenge to exchange authentic public keys in a scalable, secure, and easy to use fashion. In this paper, we propose GAnGS, a protocol for the secure exchange of authenticated information among a group of people. In contrast to prior work, GAnGS resists Groupin-the-Middle and Sybil attacks by malicious insiders, as well as infiltration attacks by malicious bystanders. GAnGS is designed to be robust to user errors, such as miscounting the number of participants or incorrectly comparing checksums. We have implemented and evaluated GAnGS on Nokia N70 phones. The GAnGS system is viable and achieves a good balance between scalability, security, and ease of use.

Corporate Governance determinants of voluntary disclosure and its effects on information asymmetry: an analysis for Iberian Peninsula listed companies.

This report focuses on the evidence about the health.consequences of smoking for women, and is intended to serve.the public health and medical communities as 'a unified source of existing scientific research. The major issues about tobacco use and women's health are examined, including

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Abstract—Architecting software systems according to the serviceoriented paradigm, and designing runtime self-adaptable systems are two relevant research areas in today’s software engineering. In this paper we address issues that lie at the intersection of these two important fields. First, we

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www.hydrol-earth-syst-sci.net/19/3667/2015/ doi:10.5194/hess-19-3667-2015

This thesis presents CraneTracker, a multi-modal sensing and communication system for monitoring migratory species at the continental level. By exploiting the robust and extensive cellular infrastructure across the continent, traditional mobile wireless sensor networks can be extended to enable reliable, low-cost monitoring of migratory species. The developed multi-tier architecture yields ecologists with unconventional behavior in-formation not furnished by alternative tracking systems at such a large scale and for a low-cost. The simulation, development and implementation of the CraneTracker soft-ware system is presented. The system is shown effective through multiple proxy deploy-

Digitising statistics handling through