Saurabh Bagchi

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Wireless reprogramming of a sensor network is useful for uploading new code or for changing the functionality of existing code. Through the process, a node should remain receptive to future code updates because reprogramming may be done multiple times during the node's lifetime. Existing reprogramming protocols, such as Deluge, achieve this by bundling the(More)
Voice over IP (VoIP) systems are gaining in popularity as the technology for transmitting voice traffic over IP networks. As the popularity of VoIP systems increases, they are being subjected to different kinds of intrusions some of which are specific to such systems and some of which follow a general pattern. VoIP systems pose several new challenges to(More)
Distributed systems with multiple interacting services, especially e-commerce systems, are suitable targets for malicious attacks because of the potential financial impact. Compared to intrusion detection, automated response has received relatively less attention. In this paper, we present the design of automated response mechanisms in an intrusion tolerant(More)
Wireless reprogramming of sensor nodes is a requirement for long-lived networks due to changes in the functionality of the software running on the nodes. The amount of information that needs to be wirelessly transmitted during reprogramming should be minimized to reduce reprogramming time and energy. In this paper, we present a multi-hop incremental(More)
Wireless reprogramming of sensor nodes is an essential requirement for long-lived networks since the software functionality changes over time. The amount of information that needs to be wirelessly transmitted during reprogramming should be minimized since reprogramming time and energy depend chiefly on the amount of radio transmissions. In this paper, we(More)
There has been significant recent interest in covert communication using timing channels. In network timing channels, information is leaked by controlling the time between transmissions of consecutive packets. Our work focuses on network timing channels and provides two main contributions. The first is to quantify the threat posed by covert network timing(More)
Wireless mesh networks (WMN) are finding increasing usage in city-wide deployments for providing network connectivity. Mesh routers in WMNs typically use multiple wireless channels to enhance the spatial-reuse of frequency bands, often with multiple radios per node. Due to the cooperative nature of WMNs, they are susceptible to many attacks that cannot be(More)
This paper presents a general knowledge model for propagating information in a content-based publish-subscribe system. The model is used to derive an efficient and scalable protocol for exactly-once delivery to large numbers (tens of thousands per broker) of content-based subscribers in either publisher order or uniform total order. Our protocol allows(More)
Sensor networks enable a wide range of applications in both military and civilian domains. However, the deployment scenarios, the functionality requirements, and the limited capabilities of these networks expose them to a wide-range of attacks against control traffic (such as wormholes, Sybil attacks, rushing attacks, etc). In this paper we propose a(More)
As smart phones grow in popularity, manufacturers are in a race to pack an increasingly rich set of features into these tiny devices. This brings additional complexity in the system software that has to fit within the constraints of the devices (chiefly memory, stable storage, and power consumption) and hence, new bugs are revealed. How this evolution of(More)