Securing the Internet of Things is critical for its successful deployment in various industries. While Machine Learning techniques have shown promise for intrusion detection in the Internet of Things, existing methods require large amounts of labeled training data; moreover, they encounter challenges with the presence of extreme class imbalance, i.e., some classes are underrepresented in the datasets used. Supervised methods rely on extensive labeled data, which can be costly and time-consuming to obtain. Class imbalance in datasets further exacerbates the challenge by skewing the model’s learning process toward the majority classes, leading to poor detection of attacks belonging to minority classes. This issue is particularly pronounced in the Internet of Things environments due to diverse devices and the varying frequency of intrusions targeting them. To overcome these challenges, we present a Few-Shot and Self-Supervised framework, called , for detecting intrusions in IoT networks. works in three phases. The first phase employs self-supervised learning to learn latent patterns and robust representations from unlabeled data. The second phase introduces Few-shot learning with contrastive training. Few-shot learning enables the model to learn from a few labeled examples, thereby eliminating the dependency on a large amount of labeled data. Contrastive Training addresses the class imbalance issue by improving the discriminative power of the model. The third phase introduces a novel K-Nearest neighbor algorithm that sub-samples the majority class instances to further reduce imbalance and improve overall performance. Experimental results based on three publicly available benchmark datasets demonstrate the efficacy of in addressing the challenges posed by the limited availability of labeled data as well as class imbalance in datasets. Our proposed framework , utilizing only of labeled data, outperforms fully supervised state-of-the-art models by up to and with respect to the metrics precision and F1 score, respectively.

Many of the privacy-preserving authentication and message dissemination approaches presented in the literature for Vehicular Ad Hoc Networks (VANETs) use pseudonyms. Under these schemes, each vehicle is assigned a set of pseudonyms by a central authority and the vehicles use these pseudonyms in all communications to preserve their privacy. Vehicles change their pseudonym (choosing from the pool of pseudonyms assigned) to prevent from being tracked. For authenticating a message sent by a vehicle using its pseudonym, certificate of the pseudonym signed by the central authority is used. When a vehicle is found to be malicious, the certificates issued for all the pseudonyms assigned to that vehicle have to be revoked. The list of certificates revoked need to be communicated to all entities that will correspond with the vehicle and they will store them in their certificate revocation list (CRL). Since the pool of pseudonyms allocated to each vehicle is large (assuming a vehicle changes pseudonym every 5 minutes, it will need more than 100,000 pseudonyms in a year) number of pseudonyms, the CRL can grow very large as the number of vehicles revoked increases which will result in high storage overhead (for storing CRL) and authentication overhead (because each time a message is received, the receiver has to check its CRL to see if that pseudonym). In this paper, we address this issue and present a timestamp based pseudonym allocation scheme.

Pseudonym based authentication schemes for vehicular ad-hoc networks (VANETs) help in ensuring privacy. However, maintaining large set of pseudonyms results in large overhead for traditional Certificate Revocation List (CRL) based solutions. In this work, we address this issue and present a cuckoo filter-based lightweight authentication scheme for VANETs which reduces the overhead associated with CRL verification. Security analysis and verification demonstrate that our protocol is robust against man-in-the-middle attacks, replay attacks, and impersonation attacks. Performance evaluation also shows that our scheme has a significantly lower authentication overhead than other related schemes.

Conventional encryption schemes are being used over the years for securing outsourced data to cloud. However, this impedes deduplication- the ability to identify and remove duplicate data from storage server. The idea of Convergent Encryption was introduced to overcome this problem which ensures that identical plaintext files will always produce identical ciphertexts and thus enabling deduplication. Nonetheless, this scheme is vulnerable to a side-channel attack called “confirmation-of-a-file” and its variant “learn-the-remaining-information” attack which breach user privacy by observing the deduplication operation. To resolve the above two seemingly contrasting issues, we propose a scheme which blends convergent encryption with a traditional access control scheme for simultaneously achieving confidentiality and deduplication. Both theoretical security analysis and experimental results show that our scheme is semantically secure and resilient against attacks. It incurs minor storage and latency overhead while performing file and block level deduplication. Furthermore, it ensures secure and fine-grained access control of outsourced data by efficiently handling key-management process.

Due to the dynamic nature of Vehicular Ad Hoc Networks (VANETs), entities in VANETs are needed to be authenticated prior to any communication between them takes place. In this paper, we present an efficient scheme for vehicles to authenticate Road Side Units (RSUs). We exploit Merkle Hash Tree (MHT) to reduce computation and communication overheads for authenticating RSUs. A detailed security analysis is carried out to demonstrate its effectiveness against message modification attack, replay attack, and message injection attack. Finally, our analysis shows that the proposed authentication scheme performs better than the ECDSA+ECDH aggregation scheme with respect to computation and communication overheads.

In this paper, we propose a cloud storage scheme which simultaneously achieves security, reliability, and deduplication. Our scheme blends convergent encryption and perfect secret sharing method to achieve confidentiality of data and encryption keys. It also achieves fault tolerance by dispersing data to multiple storage servers using Reed-Solomon erasure code. We use Merkle hash tree to authenticate users by verifying Proof of Ownership (PoW) of data for carrying out secure deduplication. Both theoretical security analysis and experimental evaluation demonstrate that our scheme is provably secure and incurs only a small overhead compared to the existing systems.

Routing protocols for Mobile Ad hoc Networks (MANETs) have been extensively studied. However, the presence of malicious nodes makes it difficult to establish a valid route. Some of the well-known source routing protocols presented in the literature which claim to establish secure routes are prone to hidden channel attacks. In this paper, we address this issue and present a novel protocol based on sanitizable signatures that establishes a secure and valid route in MANETs.

In Vehicular Ad hoc Networks (VANETs), anonymity of the nodes sending messages should be preserved, while at the same time, the law enforcement agencies should be able to trace the messages to the senders when necessary. It is also necessary that the messages sent are authenticated and delivered to the vehicles in the relevant areas quickly. In this paper, we present an efficient scheme for fast dissemination of authenticated messages in VANETs. It ensures the anonymity of the senders and also provides mechanism for law enforcement agencies to trace the messages to their senders, when necessary.

In this paper, we propose a novel geographic routing protocol, called Greedy Routing Protocol with Backtracking (GRB), for Mobile Ad Hoc Networks, which uses a simple backtracking technique to deal with voids. Performance evaluation shows GRB has much less routing overhead than that of AODV as well as GPSR. It has higher packet-delivery ratio, lower end-to-end delay, and less hop count on average than AODV.

Communication-induced checkpointing (CIC) protocols can not only bound rollback propagation but also allow each process to take checkpoints independently while at the same time ensure all checkpoints to be useful. In this paper, we present both theoretical and experimental evaluation of protocols in a particular CIC protocol family, called FEfamily in the literature, and also the FE-Lazyfamily which is the corresponding family obtained by applying ldquolazy indexing strategyrdquo to the FEfamily.

In this paper, we present an asynchronous consistent global checkpoint collection algorithm which prevents contention for network storage at the file server and hence reduces the checkpointing overhead. The algorithm has two phases: In the first phase, a process initiates consistent global checkpoint collection by saving its state tentatively and asynchronously (called tentative checkpoint) in local memory or remote stable storage if there is no contention for stable storage while saving the state; in the second phase, the message log associated with the tentative checkpoint is stored in stable storage (checkpoint finalization phase). The tentative checkpoint together with the associated message log stored in the stable storage becomes part of a consistent global checkpoint. Under our algorithm, two or more processes can concurrently initiate consistent global checkpoint collection. Every tentative checkpoint will be finalized successfully unless a failure occurs. The finalized checkpoints of each process is assigned a unique sequence number in ascending order. Finalized checkpoints with same sequence number form a consistent global checkpoint.

Mobile computing systems have many constraints such as low battery power, low bandwidth , high mobility and lack of stable storage which are not presented in static distributed systems. In this paper, we propose an efficient communication-induced checkpointing protocol for mobile computing systems. We also propose an asynchronous recovery protocol based on the checkpointing protocol. Mobile support stations control major parts of the checkpointing and recovery such as storing and tracing the checkpoints, requesting rollback and logging messages, so that mobile hosts do not incur much overhead. The recovery algorithm has no domino effect and a failed process needs to roll back to its latest checkpoint and request only a subset of the processes to rollback to a consistent checkpoint. Our recovery protocol uses selective message logging at the mobile support station to handle the messages lost due to rollback.

In cellular networks, it is vital to allocate communication channels efficiently because the bandwidth allocated for cellular communication is limited. If channels are statically allocated, as is the case in current cellular networks, a cell may run out of channels when a large number of mobile hosts move to the cell. To overcome this problem, dynamic channel allocation approaches have been proposed. Under dynamic channel allocation, channels are allocated to cells on demand, thus increasing channel utilization. Such channel allocation approaches fall under two categories, namely, centralized and distributed. Centralized approaches are neither scalable nor reliable, while distributed approaches have the potential to be both reliable and scalable. In the distributed approaches, a mobile service station is responsible for allocating channels to mobile hosts in the same cell. In cellular networks, mobile service stations may fail. In addition, the network may encounter intermittent network congestion and/or link failures. It is desirable for a channel allocation algorithm to work well, even in the presence of network congestion, link failures, and/or mobile service station failures. In this paper, we present a distributed dynamic channel allocation scheme for cellular networks that is fault-tolerant. Our approach can tolerate the failure of mobile service stations, link failure, and network congestion, and make efficient reuse of channels. We also provide results of the performance evaluation of our algorithm.

A channel allocation algorithm in a cellular network consists of two parts: a channel acquisition algorithm and a channel selection algorithm. Some of the previous works in this field focused on centralized approaches to allocating channels. But, centralized approaches are neither scalable nor reliable. Recently, distributed dynamic channel allocation algorithms have been proposed, and they have gained a lot of attention due to their high reliability and scalability. But, in most of the algorithms, the cell that wants to borrow a channel has to wait for replies from all its interference neighbors and, hence, is not fault-tolerant. In this paper, we propose a new algorithm that is fault-tolerant and makes full use of the available channels. It can tolerate the failure of mobile nodes as well as static nodes without any significant degradation in service.

Sensor networks are emerging as a new tool for habitat monitoring in nature reserves, monitoring and gathering events in hazardous environments, surveillance of buildings, and surveillance of enemy activities in a battlefield environment. Nodes in a sensor network are severely constrained by energy, storage capacity and computing power. To prolong the lifetime of the sensor nodes, designing efficient routing protocols is critical. Even though sensor networks are primarily designed for monitoring and reporting events, since they are application dependent, a single routing protocol cannot be efficient for sensor networks across all applications. We first analyze the requirements and similarities of MANETs (mobile ad hoc networks) and sensor networks. Then, we describe the existing routing protocols for sensor networks and present a critical analysis of these protocols. Finally, we compare and contrast these protocols. This comparison reveals the important features that need to be taken into consideration while designing and evaluating new routing protocols for sensor networks.

Bluetooth ad hoc networks are constrained by a master/slave configuration, in which one device takes the role of master and controls the communication with the slave devices. Piconets are small Bluetooth networks containing one master and up to seven active slave devices. In order to build larger topologies, called scatternets, the piconets must be interconnected. Scatternets are formed by allowing certain piconet members to participate in several piconets by periodically switching between them. Due to the fact that there is no scatternet formation procedure in the Bluetooth specification, numerous different approaches have been proposed. We discuss criteria for different types of scatternets and establish general models of scatternet topologies. Then we describe the state-of-the-art for Bluetooth scatternets and compare and contrast the approaches.

This article provides necessary and sufficient conditions for deadlock-free unicast and multicast routing with the path-based routing model in interconnection networks that use the wormhole switching technique. The theory is developed around three central concepts: channel waiting, False Resource Cycles , and valid destination sets . The first two concepts are suitable extensions to those developed for unicast routing by two authors of this article; the third concept has been developed by Lin and Ni. The necessary and sufficient conditions relax the requirements for deadlock-free routing, compared to techniques that provide only a sufficient condition. These necessary and sufficient conditions can be applied in a straightforward manner to prove deadlock freedom of newly developed adaptive routing algorithms for collective communication, which in turn will help in developing efficient and correct routing algorithms. The latter point is illustrated by developing two routing algorithms for multicast communication on 2D mesh architectures. The first algorithm uses fewer resources (channels) than an algorithm proposed in the literature but achieves the same adaptiveness. The second algorithm provides fully adaptive routing for both unicast and multicast messages.

Knot detection in a distributed graph is an important problem and finds applications in deadlock detection in several areas such as store-and-forward networks, distributed simulation, and distributed database systems. This paper presents an efficient distributed algorithm to detect if a node is part of a knot in a distributed graph. The algorithm requires 2e messages and a delay of 2(d+1) message hops to detect if a node in a distributed graph is in a knot (here, e is the number of edges in the reachable part of the distributed graph and d is its diameter). A significant advantage of this algorithm is that it not only detects if a node is involved in a knot, but also finds exactly which nodes are involved in the knot. Moreover, if the node is not involved in a knot, but is only involved in a cycle, then it finds the nodes that are in a cycle with that node. We illustrate the working of the algorithm with examples. The paper ends with a discussion on how the information about the nodes involved in the knot can be used for deadlock resolution and also on the performance of the algorithm.

Knot detection in a distributed graph is an important problem and finds applications in several areas such as packet switching, distributed simulation, and distributed database systems. The paper presents a distributed algorithm to efficiently detect the existence of a knot in a distributed graph. The algorithm requires 2e messages and a delay or 2(d+1) message hops to detect if a node in a distributed graph is in a knot (e is the number of edges in the reachable part of the distributed graph and d is its diameter). A significant advantage of this algorithm is that it not only detects if a node is in a knot but also finds exactly which nodes are involved in the knot.

Checkpointing algorithms are classified as synchronous and asynchronous in the literature. In synchronous checkpointing, processes synchronize their checkpointing activities so that a globally consistent set of checkpoints is always maintained in the system. Synchronizing checkpointing activity involves message overhead and process execution may have to be suspended during the checkpointing coordination, resulting in performance degradation. In asynchronous checkpointing, processes take checkpoints without any coordination with others. Asynchronous checkpointing provides maximum autonomy for processes to take checkpoints; however, some of the checkpoints taken may not lie on any consistent global checkpoint, thus making the checkpointing efforts useless. Asynchronous checkpointing algorithms in the literature can reduce the number of useless checkpoints by making processes take communication induced checkpoints besides asynchronous checkpoints. We call such algorithms quasi-synchronous. In this paper, we present a theoretical framework for characterizing and classifying such algorithms. The theory not only helps to classify and characterize the quasi-synchronous checkpointing algorithms, but also helps to analyze the properties and limitations of the algorithms belonging to each class. It also provides guidelines for designing and evaluating such algorithms.

Consistent global checkpoints have many uses in distributed computations. A central question in applications that use consistent global checkpoints is to determine whether a consistent global checkpoint that includes a given set of local checkpoints can exist. Netzer and Xu (1995) presented the necessary and sufficient conditions under which such a consistent global checkpoint can exist, but they did not explore what checkpoints could be constructed. In this paper, we prove exactly which local checkpoints can be used for constructing such consistent global checkpoints. We illustrate the use of our results with a simple and elegant algorithm to enumerate all such consistent global checkpoints.

In this paper, we propose a quasi-synchronous checkpointing algorithm and a low-overhead recovery algorithm based on it. The checkpointing algorithm preserves process autonomy by allowing them to take checkpoints asynchronously and uses communication-induced checkpoint coordination for the progression of the recovery line which helps bound rollback propagation during a recovery. Thus, it has the easeness and low overhead of asynchronous checkpointing and the recovery time advantages of synchronous checkpointing. There is no extra message overhead involved during checkpointing and the additional checkpointing overhead is nominal. The algorithm ensures the existence of a recovery line consistent with the latest checkpoint of any process all the time. The recovery algorithm exploits this feature to restore the system to a state consistent with the latest checkpoint of a failed process. The recovery algorithm has no domino effect and a failed process needs only to rollback to its latest ch...