No abstract

Mobile smart devices and services have become an integral part of our daily life. In this context there are many compelling scenarios for mobile device users to share resources. A popular example is tethering. However, sharing resources also raises privacy and security issues. In this paper, we present CrowdShare, a complete framework and its (Android) implementation for secure and private resource sharing among nearby devices. CrowdShare provides pseudonymity for users, accountability of resource usage, and the possibility of specifying access control in terms of social network relationships. Further, CrowdShare preserves secure connectivity between nearby devices even in the absence of the mobile infrastructure. We have implemented CrowdShare on Android devices and report good performance results.

In this paper, we propose a new rate control algorithm for conversational multimedia flows. In our approach, along with Real-time Transport Protocol (RTP) media packets, we propose sending redundant packets to probe for available bandwidth. These redundant packets are Forward Error Correction (FEC) encoded RTP packets. A straightforward interpretation is that if no losses occur, the sender can increase the sending rate to include the FEC bit rate, and in the case of losses due to congestion the redundant packets help in recovering the lost packets. We also show that by varying the FEC bit rate, the sender is able to conservatively or aggressively probe for available bandwidth. We evaluate our FEC-based Rate Adaptation (FBRA) algorithm in a network simulator and in the real-world and compare it to other congestion control algorithms.

Abstract. We present the design and implementation of the PeerShare, a system that can be used by applications to securely distribute sensitive data to social contacts of a user. PeerShare incorporates a generic framework that allows different applications to distribute data with different security requirements. By using interfaces available from existing popular social networks, PeerShare is designed to be easy to use for both end users as well as developers of applications. PeerShare can be used to distribute shared keys, public keys and any other data that need to be distributed with authenticity and confidentiality guarantees to an authorized set of recipients, specified in terms of social relationships. We have used PeerShare already in three different applications and plan to make it available for developers.

Mobile opportunistic networking utilizes device-to-device communication to provide messaging and content sharing mechanisms between mobile users without the need for supporting infrastructure networks. However, enabling opportunistic networking in practice requires a sufficient number of users to download, install, and run the respective routing and application software to provide sufficient node density, and thus connectivity for the network to actually function. In this paper, we explore reaching out to nodes that have not (yet) installed any dedicated software to: (1) allow them to access public content in an opportunistic network to possibly seed their interest and (2) instrument them to assist as (limited) message carriers to improve connectivity. We report on our system design and implementation and offer performance insights gained from simulations and initial experiments.