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Fog-assisted Internet-of-Things (Fog-IoT) systems are deployed in remote and unprotected environments, making them vulnerable to security, privacy, and trust challenges. Existing studies propose security schemes and trust models for these systems. However, mitigation of insider attacks, namely, blackhole, sinkhole, sybil, collusion, self-promotion, and privilege escalation, has always been a challenge and mostly carried out by the legitimate nodes. Compared to other studies, this article proposes a framework featuring attribute-based access control and trust-based behavioral monitoring to address the challenges mentioned above. The proposed framework consists of two components, the security component (SC) and the trust management component (TMC). SC ensures data confidentiality, integrity, authentication, and authorization. TMC evaluates Fog-IoT entities’ performance using a trust model based on a set of Quality of Service (QoS) and network communication features. Subsequently, trust is embedded as an attribute within SC’s access control policies, ensuring that only trusted entities are granted access to fog resources. Several attacking scenarios, namely, Denial of Service (DoS), Distributed DoS, probing, and data theft are designed to elaborate on how the change in trust triggers the change in access rights and, therefore, validates the proposed integrated framework’s design principles. The framework is evaluated on a Raspberry Pi 3 Model B+ to benchmark its performance in terms of time and memory complexity. Our results show that both SC and TMC are lightweight and suitable for resource-constrained devices.

Recently, D/DoS attacks have been launched by zombie IoT devices in smart home networks. They pose a great threat to network systems with Application Layer DDoS attacks being especially hard to detect due to their stealth and seemingly legitimacy. In this paper, we propose ForChaos, a lightweight detection algorithm for IoT devices, which is based on forecasting and chaos theory to identify flooding and DDoS attacks. For every time-series behaviour collected, a forecasting-technique prediction is generated, based on a number of features, and the error between the two values is calculated. In order to assess the error of the forecasting from the actual value, the Lyapunov exponent is used to detect potential malicious behaviour. In NS-3 we evaluate our detection algorithm through a series of experiments in flooding and slow-rate DDoS attacks. The results are presented and discussed in detail and compared with related studies, demonstrating its effectiveness and robustness.

Attribute-based encryption (ABE) schemes and their variations are often applied to preserve the privacy of data. In particular, ABE schemes proposals are resilient to multiple attacks, including attacks in interception, interruption, modification, fabrication, unauthorized authentication, and access of data. Existing proposals have several limitations, such as the generation, verification, and distribution of digital certificates incur extra computation and communication overhead which are not suitable for resource-constrained computing. Furthermore, in most of the ABE schemes, a certification authority (CA) generates the public/secret keys according to a set of attributes. However, the compromise of CA can endanger the secret keys, therefore, the secrecy of encrypted messages. Some of the existing ABE schemes are based on bilinear pairing that requires large security parameters, which make ABE schemes unsuitable for resource-constrained computing devices. The current ABE proposals [1, 2, 3, 4] are complex because they require implementing large-number security parameters (i.e., 2048-bit or 4096-bit size) to achieve 2128 security. Besides that, those ABE schemes consider a CA with an active role in the application process. The CA generates and distributes secret keys to devices or users. Nonetheless, sharing private attributes with the CA can risk data and user privacy, since the CA can also decrypt messages, depending on the application scenario, and retrieve the data. Moreover, the compromise of CA poses a risk to the communication secrecy between the sender and the receiver. In addition, some studies propose symmetric key schemes for resource-constrained devices. However, in large-scale networked systems, the symmetric key management becomes very complex and inefficient. The symmetric-key deployment often requires a separate protocol for session key agreement and generation. In IoT networks where mostly short-sized data is exchanged, symmetric key encryption schemes are often subject to ciphertext-only attacks. In this paper, we will discuss how we can generate efficient ABE schemes based on elliptic curve cryptographic (ECC) techniques without the use of a CA. ECC-based ABE schemes require smaller-number security parameters (i.e., 256 or 512 bits) for achieving at least 2128 computational security that makes them efficient in resource-constrained computing devices. In particular, efficient ABE schemes, such as [5], are based on the computational Diffie-Hellman assumptions and their derivatives. Using such an assumption, we can perform elliptic curve operations, addition and multiplication, in a group without compromising the security of the ABE scheme. In other words, an adversary or oracle cannot efficiently “guess” or “find” the secret asymmetric key. ABE schemes are usually enclosed by assumptions that are necessary for the deployed systems. In addition, ABE schemes consist of the Key pair generation, encryption, and decryption algorithms, even though few ABE proposals additionally include key pair update and key pair revocation algorithms [5]. The key pair generation algorithm considers the secret attributes of a device or user. The algorithm takes as input a security parameter λ and a set of secret attributes AS. λ consists of a long string of 1s in a chosen finite field that defines the access structure and the length of the secret keys and messages. It outputs the public/secret key pair (PK, SK) that is either offline or online and is distributed to the involved entities, i.e., devices or users. The encryption algorithm takes as input the public key of a device PK, the access policy P, and a message M. It outputs a ciphertext CT that is exchanged in a hostile environment. On the contrary, the decryption algorithm takes as input the secret key SK and ciphertext CT and outputs the plaintext message M. Obviously, the key pair generation algorithm sets the mathematical foundations that connect the key pair, whereas encryption and decryption algorithms conceal and reveal the actual data during online transmission and exposure. If the secret or shared attributes of an entity are changed, for any reason, then all the keys should be updated. The key pair update algorithm will regenerate the public/secret (PK/SK) key pair. In the key pair update procedure, the updated secret attributes AS are considered as input to the algorithm and new key pair (PK / SK ) is regenerated. In the key pair revocation algorithm, the keys are revoked by an entity or due to the malicious behaviour of some users/devices. Three cases for key revocation have been identified: (1) Legitimate revoke: in this case, the key pair can be revoked due to a system update, expiration date, and scheduled maintenance of the networked system. (2) Malicious activity: in this case, the key revocation may take place due to the malicious behaviour which might be observed and/or reported by an entity of the networked system. (3) Attribute update: in this case, the change in the attribute set can trigger a new key revocation procedure. In literature, the ABE algorithms are theoretically assessed by proving that the mathematical foundations hold in a malicious environment. Likewise, the ABE algorithms are assessed by their computational and memory complexity as well as by their practical implementation in real devices or the simulated network. In principle, the security of the ABE schemes is carefully analysed to ensure security against popular attacks: (i) Computing the secret key SK from the public key PK, (ii) Computing the secret key SK from multiple ciphertexts (i.e., chosen ciphertext attack), (iii) it can be shown by a reduction that the computational problem in an ABE scheme is at least as hard as the discrete logarithm problem (DLP) and (iv) the ABE scheme is secure against an adversary A with knowledge of the shared attribute set AK for deriving the secret key SK by a collision attack. The security and privacy challenges posed by resource-constrained systems affect the heterogeneous nature of devices with varying degrees of computation and storage capacity. It is therefore essential to find lightweight solutions which eliminate the need for applying different security schemes per system. The existing public-key encryption and attribute-based encryption schemes are often computationally expensive, therefore, not suitable for resource-constrained devices. Moreover, the sharing of attributes with a certification authority risks the privacy of devices if CA has been compromised. New ABE schemes should not endanger the secrecy of messages among devices if CA is compromised. It is also essential for researchers to propose schemes based on mathematical constructions that are proven to be secure and light, such as elliptic curve cryptography which supports smaller key sizes and is highly suitable for resource-constrained devices.

—Short Message Service (SMS) is a widely used communication medium for mobile applications, such as banking, social\ud networking, and e-commerce. Applications of SMS services also include real-time broadcasting messages, such as notification of\ud natural disasters (e.g., bushfires and hurricane) and terrorist attacks, and sharing the current whereabouts to other users, such as\ud notifying urgent business meeting information, transmitting quick information in the battlefield to multiple users, notifying current\ud location to our friends and sharing market information. However, traditional SMS is not designed with security in mind (e.g., messages\ud are not securely sent). It is also possible to extract international mobile subscriber identity of the mobile user. In the literature, there is\ud no known protocol that could enable secure transmission of SMS from one user to multiple users simultaneously. In this paper, we\ud introduce a batch verification authentication and key agreement protocol, BVPSMS, which provides end-to-end message security over\ud an insecure communication channel between different mobile subscribers. Specifically, the proposed protocol securely transmits SMS\ud from one mobile user to multiple users simultaneously. The reliability of the protocol is discussed along with an algorithm to detect\ud malicious user request in a batch. We then evaluate the performance of the proposed protocol in terms of communication and\ud computation overheads, protocol execution time, and batch and re-batch verification times. The impacts of the user mobility, and the\ud time, space and cost complexity analysis are also discussed. We then present a formal security proof of the proposed protocol. To the\ud best of our knowledge, this is the first provably-secure batch verification protocol that delivers end-to-end SMS security using\ud symmetric keys.

This survey investigates the contributions of research into the detection of ransomware malware using machine learning and deep learning algorithms. The main motivations for this study are the destructive nature of ransomware, the difficulty of reversing a ransomware infection, and how important it is to detect it before infecting a system. Machine learning is coming to the forefront of combatting ransomware, so we attempted to identify weaknesses in machine learning approaches and how they can be strengthened. The threat posed by ransomware is exceptionally high, with new variants and families continually being found on the internet and dark web. Recovering from ransomware infections is difficult, given the nature of the encryption schemes used by them. The increase in the use of artificial intelligence also coincides with this boom in ransomware. The exploration into machine learning and deep learning approaches when it comes to detecting ransomware poses high interest because machine learning and deep learning can detect zero-day threats. These techniques can generate predictive models that can learn the behaviour of ransomware and use this knowledge to detect variants and families which have not yet been seen. In this survey, we review prominent research studies which all showcase a machine learning or deep learning approach when detecting ransomware malware. These studies were chosen based on the number of citations they had by other research. We carried out experiments to investigate how the discussed research studies are impacted by malware evolution. We also explored the new directions of ransomware and how we expect it to evolve in the coming years, such as expansion into IoT (Internet of Things), with IoT being integrated more into infrastructures and into homes.

In this chapter, we discussed the importance of bio-inspired techniques in the field of intrusion detection. A brief explanation is given on the most popular cyberattacks, such as DDoS attacks, as well as the most popular concepts of bio-inspired algorithm detection.

Botnet use is on the rise, with a growing number of botmasters now switching to the HTTP-based C&C infrastructure. This offers them more stealth by allowing them to blend in with benign web traffic. Several works have been carried out aimed at characterising or detecting HTTP-based bots, many of which use network communication features as identifiers of botnet behaviour. In this paper, we present a survey of these approaches and the network features they use in order to highlight how botnet traffic is currently differentiated from normal traffic. We classify papers by traffic types, and provide a breakdown of features by protocol. In doing so, we hope to highlight the relationships between features at the application, transport and network layers.

The propagation approach of a botnet largely dictates its formation, establishing a foundation of bots for future exploitation. The chosen propagation method determines the attack surface and, consequently, the degree of network penetration, as well as the overall size and the eventual attack potency. It is therefore essential to understand propagation behaviours and influential factors in order to better secure vulnerable systems. Whilst botnet propagation is generally well studied, newer technologies like IoT have unique characteristics which are yet to be thoroughly explored. In this paper, we apply the principles of epidemic modelling to IoT networks consisting of wireless sensor nodes. We build IoT-SIS, a novel propagation model which considers the impact of IoT-specific characteristics like limited processing power, energy restrictions, and node density on the formation of a botnet. Focusing on worm-based propagation, this model is used to explore the dynamics of spread using numerical simulations and the Monte Carlo method to discuss the real-life implications of our findings.

Botnet research frequently draws on concepts from other fields. An example is the use of epidemiological models when studying botnet propagation, which facilitate an understanding of bot spread dynamics and the exploration of behavioural theory. Whilst the literature is rich with these models, it is lacking in work aimed at connecting the insights of theoretical research with day-to-day practice. To address this, we look at botnets through the lens of implementation science, a discipline from the field of translational research in health care, which is designed to evaluate the implementation process. In this paper, we explore key concepts of implementation science, and propose a framework-based approach to improve the provision of security measures to network entities. We demonstrate the approach using existing propagation models, and discuss the role of implementation science in malware defence.

The challenge for fast and low-cost deployment of ubiquitous personalized e-Health services has prompted us to propose a new framework architecture for such services. We have studied the operational features and the environment of e-Health services and we led to a framework structure that extends the European Telecommunications Standards Institute (ETSI)/Parlay architecture, which is used for the deployment of standardized services over the next generation IP networks. We expanded the ETSI/Parlay architecture with new service capability features as well as sensor, profiling, and security mechanisms. The proposed framework assists the seamless integration, within the e-Health service structure, of diverse facilities provided by both the underlying communication and computing infrastructure as well as the patient's bio and context sensor networks. Finally, we demonstrate the deployment of a telemonitoring service in smart home environment based on the proposed framework architecture.

As ad-hoc networks have different characteristics from a wired network, the intrusion detection techniques used for wired networks are no longer sufficient and effective when adapted directly to a wireless ad-hoc network. In this article, first τhe security challenges in intrusion detection for ad-hoc networks are identified and the related work for anomaly detection is discussed. We then propose a layered intrusion detection framework, which consists of collection, detection and alert modules that are handled by local agents. The collection, detection and alert modules are uniquely enabled with the main operations of ad-hoc networking, which are found at the OSI link and network layers. The proposed modules are based on interpolating polynomials and linear threshold schemes. An experimental evaluation of these modules shows their efficiency for several attack scenarios, such as route logic compromise, traffic patterns distortion and denial of service attacks.

Due to smart grid’s complex nature and criticality as an infrastructure, it is important to understand the key actors on each domain in depth so the potential vulnerabilities that can rise are identified. Furthermore, the correct identification of threats affecting the smart grid’s normal functionality must be realised, as well as what impact these threats can have so appropriate countermeasures are implemented. In this paper a list of vulnerabilities that weaken the smart grid is outlined. Also structured analysis of attacks regarding the three key security objectives across the different layers is presented along with appropriate examples applicable to the smart grid infrastructure and what impact each of them has to the smart grid on each case. Finally, a set of new attack scenarios that focus on attacks being initiated from the smart home part of the smart grid is described targeting these security objectives with the potential consequences they can cause to the smart grid.

When security of a given network architecture is not properly designed from the beginning, it is difficult to preserve confidentiality, authenticity, integrity and non-repudiation in practical networks. Unlike traditional mobile wireless networks, ad hoc networks rely on individual nodes to keep all the necessary interconnections alive. In this article we investigate the principal security issues for protecting mobile ad hoc networks at the data link and network layers. The security requirements for these two layers are identified and the design criteria for creating secure ad hoc networks using multiple lines of defense against malicious attacks are discussed.

Security has recently become an important issue that needs to be addressed in an era where governments are investing heavily into preventive measures against cyber-crime that includes denial of service attacks, tampering attacks and eavesdropping attacks, among others. These types of malpractice are foreseen as threats in future 5G scenarios, since confidential information will be downloaded, uploaded and processed via the upcoming 5G systems. Furthermore, the emergence of the 5G era requires the integration of multiple existing advanced technologies with innovative new techniques, which will result in many security breaches. Thus, in this chapter, we present representative examples of potential threats and attacks against the main components of 5G systems in order to shed light on the future security issues and challenges in the upcoming 5G era.

In a Multiple Cloud Collaborative Environment (MCCE), cloud users and cloud providers interact with each other via a brokering service to request and provision cloud services. The brokering service considers several pieces of data to broker the best deal between users and providers which can subsequently risk the privacy and security of MCCE. In this paper, we propose a Privacy Preserving Attribute-Based Encryption (PP-ABE) scheme which protects MCCE from a compromised broker. The proposed encryption scheme preserves the privacy by employing data access policy over sets of attributes. The identifying attributes are anonymoized using pseudonyms. The data access policy is further anonymized so as it remains unknown to unauthorized parties. The PP-ABE achieves unlinkability between different data items which flows through the collaborative cloud environment and preserves the privacy of cloud users and cloud providers.

Electronic devices we use on a daily basis collect sensitive information without preserving user’s privacy. In this paper, we propose the lord of the sense (LotS), a privacy pre- serving reputation system for participatory sensing applications. Our system maintains the privacy and anonymity of information with the use of cryptographic techniques and combines voting approaches to support users’ reputation. Furthermore, LotS maintains accountability by tracing back a misbehaving user while maintaining k-anonymity. A detailed security analysis is presented with the current advantages and disadvantages of our system.

In this paper we propose a secure anonymous voting scheme (SAnoVS) for re-clustering in the ad-hoc network. SAnoVS extends our previous work of degree-based clustering algorithms by achieving anonymity and confidentiality of the voting procedure applied to select new cluster heads. The security of SAnoVS is based on the difficulty of computing discrete logarithms over elliptic curves, the intractability of inverting a one-way hash function and the fact that only neighboring nodes contribute to the generation of a shared secret. Furthermore, we achieve anonymity since our scheme does not require any identification information as we make use of a polynomial equation system combined with pseudo-random coordinates. The security analysis of our scheme is demonstrated with several attacks scenarios.examined with several attack scenarios and experimental results.

Nowadays, the patient-centric healthcare approach is focused on ubiquitous healthcare services. Furthermore, the adoption of cloud computing technology leads to more efficient ubiquitous healthcare systems. Moreover, the personalization of the delivery of ubiquitous healthcare services is enabled with the introduction of user profiles. In this paper, we propose five generic healthcare profile structures corresponding to the main categories of the participating entities included in a typical ubiquitous healthcare system in a cloud computing environment. In addition, we propose a profile management system incorporating smart card technology to increase its efficiency and the quality of the provided services of the ubiquitous healthcare system.

This paper proposes a decentralized trust establishment protocol for mobile ad hoc networks (MANETs), where nodes establish security associations. In order to achieve privacy and security, we use homomorphic encryption and polynomial intersection so as to find the intersection of two sets. The first set represents a list of recommenders of the initiator and the second set is a list of trusted recommenders of the responder. The intersection of the sets represents a list of nodes that recommend the first node and their recommendations are trusted by the second node. In our experimental results we show that our scheme is effective even if there are 30 trusted nodes.

In this paper we propose a user dependent scheme for enhancing security of the transmitted content in the future telecommunication systems. In order to achieve a higher level of security we introduce a scheme where the user identity gets involved in the encryption/decryption processes using an additional component for the block cipher which represents the user’s behavioural model. Applying such a scheme, in addition to introducing more difficulties to an attacker due to the user dependency of the cipher algorithm, gives the mobile operator the opportunity to ensure that a licensed service has not been shared by the customer. To show the feasibility of our approach we use the concept of invertible Boolean functions as an example.

In this paper, a Polymorphic Encryption Algorithm (PEA), based on basic quantum computations, is proposed for the encryption of binary bits. PEA is a symmetric key encryption algorithm that applies different combinations of quantum gates to encrypt binary bits. PEA is also polymorphic since the states of the shared secret key control the different combinations of the ciphertext. It is shown that PEA achieves perfect secrecy and is resilient to eavesdropping and Trojan horse attacks. A security analysis of PEA is also described.

This paper proposes a multiplayer game to prevent Distributed Denial of Service attack (DDoS) in ad hoc networks. The multiplayer game is based on game theory and cryptographic puzzles. We divide requests from nodes into separate groups which decreases the ability of malicious nodes to cooperate with one another in order to effectively make a DDoS attack. Finally, through our experiments we have shown that the total overhead of the multiplayer game as well as the the total time that each node needs to be served is affordable for devices that have limited resources and for environments like ad hoc networks where nodes must exchange information really fast.

Picture archiving and communication systems (PACS) are typical information systems, which may be undermined by unauthorized users who have illegal access to the systems. This paper proposes a role-based access control framework comprising two main components – a content-based steganographic module and a reversible watermarking module, to protect mammograms on PACSs. Within this framework, the content-based steganographic module is to hide patients’ textual information into mammograms without changing the important details of the pictorial contents and to verify the authenticity and integrity of the mammograms. The reversible watermarking module, capable of masking the contents of mammograms, is for preventing unauthorized users from viewing the contents of the mammograms. The scheme is compatible with mammogram transmission and storage on PACSs. Our experiments have demonstrated that the content-based steganographic method and reversible watermarking technique can effectively protect mammograms at PACS.

In this paper we propose a new client puzzle approach to prevent Denial of Service (DoS) attacks in ad hoc networks. Each node in the network first solves a computational problem and with the solution has to create and solve a client puzzle. By combining computational problems with puzzles, we improve the efficiency and latency of the communicating nodes and resistance in DoS attacks. Experimental results show the effectiveness of our approach.

Nowadays, there is a significant lack of generic application frameworks providing third party developers with the appropriate mechanisms for building ubiquitous context-aware healthcare applications over medical heterogeneous networks. In this paper, we propose a new framework integrating context-aware and security mechanisms with mechanisms that allow the ease exploitation of the core networks' functionality to enable third party developers to build reliable and secure ubiquitous context-aware healthcare applications over medical heterogeneous networks.

This chapter presents the concept of Smart Home, describes the Smart Home networking technologies and discusses the main issues for ensuring security in a Smart Home environment. Nowadays, the integration of current communication and information technologies within the dwelling has led to the emergence of Smart Homes. These technologies facilitate the building of Smart Home environments in which devices and systems can communicate with each other and can be controlled automatically in order to interact with the household members and improve the quality of their life. However, the nature of Smart Home environment, the fact that it is always connected to the outside world via Internet and the open security back doors derived from the household members raise many security concerns. Finally, by reviewing the existing literature regarding Smart Homes and security issues that exist in Smart Home environments, the authors envisage to provide a base to broaden the research in Smart Home security.

During the past few years a lot of PKI (Public Key Infrastructures) infrastructures have been proposed for healthcare networks in order to ensure secure communication services and exchange of data among healthcare professionals. However, there is a plethora of challenges in these healthcare PKI infrastructures. Especially, there are a lot of challenges for PKI infrastructures deployed over large-scale healthcare networks. In this paper, we propose a PKI infrastructure to ensure security in a large-scale Internet-based healthcare network connecting a wide spectrum of healthcare units geographically distributed within a wide region. Furthermore, the proposed PKI infrastructure facilitates the trust issues that arise in a large-scale healthcare network including multi-domain PKI infrastructures.

Ad hoc networks are created dynamically and maintained by individual nodes comprising the network. They do not require a preexisting architecture for communication purposes and they do not rely on any type of wired infrastructure; in an ad hoc network, all communication occurs through a wireless medium. With current technology and the increasing popularity of notebook computers, interest in ad hoc networks has peaked. Future advances in technology will allow us to form small ad hoc networks on campuses, during conferences, and even in our own home environment. Further, the need for easily portable ad hoc networks in rescue missions and in situations in rough terrain are becoming extremely common.

In this paper we revisit some considerations relative to the performance of re-clustering algorithms in MANET. We recommend that for a secure MANET the design of re-clustering algorithms should not only provide for clustering stability, but also for network robustness in terms of network connectivity, of message reliability, of tolerance against the attacks that target the cluster head nodes and of tolerance to random node failures due to energy drains. We also take into account the possibility of malicious users that might thwart the network protocol by advertising false topology information. We propose a distributed mechanism that for unbiased cluster head election first demands certain levels of consistency to be reached among the nodes.

Ad hoc networks are dynamic peer-to-peer wireless networks composed of a collection of nodes which employ wireless transmission methods in a self-organized way without relying on fixed infrastructure or predetermined connectivity. Such networks pose great challenges in group communication. In this paper, we propose an efficient group key agreement and recovery mechanism based on key escrow systems for ad hoc networks. Nodes randomly change their operation and perform authentication services for specific groups.

Biometric templates are subject to modifications for identity fraud especially when they are stored in databases. In this paper, a new approach to protecting biometric templates with image watermarking techniques is proposed. The novelty of this approach is that we have combined lattice and block-wise image watermarking techniques to maintain image quality along with cryptographic techniques to embed fingerprint templates into facial images and vice-versa. Thus, protecting them from being modified.

In mobile ad hoc networks (MANET) specific Intrusion Detection Systems (IDSs) are needed to safeguard them since traditional intrusion prevention techniques are not sufficient in the protection of MANET. In this paper we present an intrusion detection engine based on neural networks combined with a protection method, which is based on watermarking techniques. We exploit the advantages of information visualization and machine learning techniques in order to achieve intrusion detection. Then, we authenticate the maps produced by the application of the intelligent techniques using a novel combined watermarking embedded method. The performance of the proposed model is evaluated under different traffic conditions, mobility patterns and visualization metrics, showing its high efficiency.

An ad hoc network is a collection of nodes that do not need to rely on a predefined infrastructure to keep the network connected. Nodes communicate amongst each other using wireless radios and operate by following a peer-to-peer network model. In this article we investigate authentication in a layered approach, which results to multiple lines of defense for mobile ad hoc networks. The layered security approach is described and design criteria for creating secure ad hoc network using multiple authentication protocols are analyzed. The performance of several such known protocols, which are based on challenge-response techniques, is presented through simulation results.

Security of mobile ad hoc networks (MANET) has become a more sophisticated problem than security in other networks, due to the open nature and the lack of infrastructure of such networks. In this paper, the security challenges in intrusion detection and authentication are identified and the different types of attacks are discussed. We propose a two-phase detection procedure of nodes that are not authorized for specific services and nodes that have been compromised during their operation in MANET. The detection framework is enabled with the main operations of ad hoc networking, which are found at the link and network layers. The proposed framework is based on zero knowledge techniques, which are presented through proofs.

A5/1 is the strong encryption algorithm which protects the air interface of the GSM cellular network. However, in the Fast Software Encryption Workshop 2000, two attacks, the biased birthday attack and the random subgraph attack against A5/1 were presented. We propose new security enhancements to improve A5/1 encryption algorithm from the biased birthday attack and random subgraph attack in order to be used in future mobile communication systems. The improvements that make both attacks impractical are based on the clocking mechanism of the registers, and their key setup routine. Furthermore, we have increased the linear complexity of A5/1 to make the solution of the linear equations impractical in real time systems. Finally, both original and modified versions of A5/1 were implemented easily in a complex programmable logic device (CPLD). The modified version of A5/1 is fast, easy to implement, and most important small in size which makes it ideal for future mobile terminals.

Encryption in wireless networks is essential to protect sensitive information and to prevent fraud. Furthermore, wireless devices, such as palmtops, bluetooth devices, and mobiles phones require an efficient encryption algorithm which is secure and small, fast and simple to implement. There are several stream ciphers available with the best known being A5/1 used in GSM and RC4 used in 802.11 standards. However, these stream ciphers are weak against cryptographic attacks [1] [2] [3] [4] [5] [6]. In this paper, a new synchronous stream cipher (Alpha1) is proposed. Alpha1 is robust against these attacks, small, fast and very simple to implement in small wireless devices with low processing power and size (i.e. bluetooth, mobile phones, access points etc.).

It is essential for future mobile communication systems to support different media types such as audio, video. There is also an increasing need to preserve the confidentiality, data integrity, and authenticity of these media to prevent fraud. In this paper, modifications to the wireless application protocol (WAP) are proposed to enable real time voice and video transmission in future mobile communication systems through a secure communication protocol.

It is essential to enable public key schemes in future mobile systems to solve current problems in authentication and key management for end-to-end security. In this paper, we propose new procedures for enabling public key schemes in future mobile terminals. The proposed procedures are based on the complex public key computations that can be performed either in the SIM card or in the terminal itself. Multiple cryptoprocessors are also used to decrease the processing time required to perform the complex public key computations.

In this paper, we focus on attacks and defense mechanisms in additive reputation systems. We start by surveying the most important protocols that aim to provide privacy between individual voters. Then, we categorize attacks against additive reputation systems considering both malicious querying nodes and malicious reporting nodes that collaborate in order to undermine the vote privacy of the remaining users. To the best of our knowledge this is the first work that provides a description of such malicious behavior under both semi-honest and malicious model. In light of this analysis we demonstrate the inefficiencies of existing protocols.

During the past few years, a lot of effort has been invested in research and development of eHealth tele-monitoring systems that will provide many benefits for healthcare delivery from the healthcare provider to the patient's home. However, there is a plethora of security requirements in eHealth tele-monitoring systems. Data integrity of the transferred medical data is one of the most important security requirements that should be satisfied in these systems, since medical information is extremely sensitive information, and even sometimes life threatening information. In this paper, we present a data integrity mechanism for eHealth tele-monitoring system that operates in a smart home environment. Agent technology is applied to achieve data integrity with the use of cryptographic smart cards. Furthermore, the overall security infrastructure and its various components are described.