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2020-07-13
Xiao, Yonggang, Liu, Yanbing.  2019.  BayesTrust and VehicleRank: Constructing an Implicit Web of Trust in VANET. IEEE Transactions on Vehicular Technology. 68:2850–2864.
As Vehicular Ad hoc Network (VANET) features random topology and accommodates freely connected nodes, it is important that the cooperation among the nodes exists. This paper proposes a trust model called Implicit Web of Trust in VANET (IWOT-V) to reason out the trustworthiness of vehicles. Such that untrusted nodes can be identified and avoided when we make a decision regarding whom to follow or cooperate with. Furthermore, the performance of Cooperative Intelligent Transport System (C-ITS) applications improves. The idea of IWOT-V is mainly inspired by web page ranking algorithms such as PageRank. Although there does not exist explicit link structure in VANET because of random topology and dynamic connections, social trust relationship among vehicles exists and an implicit web of trust can be derived. To accomplish the derivation, two algorithms are presented, i.e., BayesTrust and VehicleRank. They are responsible for deriving the local and global trust relationships, respectively. The simulation results show that IWOT-V can accurately identify trusted and untrusted nodes if enough local trust information is collected. The performance of IWOT-V affected by five threat models is demonstrated, and the related discussions are also given.
Qiu, Yu, Wang, Jin-Yuan, Lin, Sheng-Hong, Wang, Jun-Bo, Lin, Min.  2019.  Secrecy Outage Probability Analysis for Visible Light Communications with SWIPT and Random Terminals. 2019 11th International Conference on Wireless Communications and Signal Processing (WCSP). :1–6.
This paper investigates the physical-layer data secure transmission for indoor visible light communications (VLC) with simultaneous wireless information and power transfer (SWIPT) and random terminals. A typical indoor VLC system including one transmitter, one desired information receiver and one energy receiver is considered. The two receivers are randomly deployed on the floor, and the random channel characteristics is analyzed. Based on the possibility that the energy receiver is a passive information eavesdropper, the secrecy outage probability (SOP) is employed to evaluate the system performance. A closed-from expression for the lower bound of the SOP is obtained. For the derived lower bound of SOP, the theoretical results match the simulation results very well, which indicates that the derived lower bound can be used to evaluate the secrecy performance. Moreover, the gap between the results of the lower bound and the exact simulation results is also small, which verifies the correctness of the analysis method to obtain the lower bound.
Lee, Yong Up, Kang, Kyeong-Yoon, Choi, Ginkyu.  2019.  Secure Visible Light Encryption Communication Technique for Smart Home Service. 2019 IEEE 9th Annual Computing and Communication Workshop and Conference (CCWC). :0827–0831.
For the security enhancement of the conventional visible light (VL) communication which allows the easy intrusion by adjacent adversary due to visible signal characteristic, the VL communication technique based on the asymmetric Rivest-Shamir-Adleman (RSA) encryption method is proposed for smart indoor service in this paper, and the optimal key length of the RSA encryption process for secure VL communication technique is investigated, and also the error performance dependent on the various asymmetric encryption key is analyzed for the performance evaluation of the proposed technique. Then we could see that the VL communication technique based on the RSA encryption gives the similar RMSE performance independent of the length of the public or private key and provides the better error performance as the signal to noise ratio (SNR) increases.
Ge, Hong, Dai, Jianxin, Huang, Bo, Wang, Jin-Yuan.  2019.  Secrecy Rate Analysis for Visible Light Communications Using Spatial Modulation. 2019 IEEE 21st International Conference on High Performance Computing and Communications; IEEE 17th International Conference on Smart City; IEEE 5th International Conference on Data Science and Systems (HPCC/SmartCity/DSS). :1241–1248.
This paper mainly investigates the physical layer security for visible light communication (VLC) based on spatial modulation (SM). The indoor VLC system includes multiple transmitters, a legitimate receiver and an eavesdropper. In the system, we consider two constraints of the input signal: non-negative and dimmable average optical intensity constraints. According to the principle of information theory and the spatial modulation scheme of uniform selection (US), the upper and the lower bounds on the secrecy rate for SM based VLC are derived, respectively. Numerical results show that the performance gap between the upper and lower bounds of the secrecy rate is small and relatively close, which indicates that the derived secrecy rate bounds can be used to evaluate the system performance. Moreover, when the number of transmitters is set to be one, the spatial modulation disappears, and the secrecy rate bounds in this paper are consistent with the existing results. To further improve the secrecy performance, a channel adaptive selection (CAS) scheme is proposed for selecting the active transmitter. Numerical result indicates that the CAS scheme has better performance than the US scheme.
Wu, Xiaoge, Zhang, Lin.  2019.  Chaos-based Information Rotated Polar Coding Scheme for Visible Light Wiretap Channel. 2019 International Conference on Computing, Networking and Communications (ICNC). :864–868.
In this paper, we present a chaos-based information rotated polar coding scheme for enhancing the reliability and security of visible light communication (VLC) systems. In our scheme, we rotate the original information, wherein the rotation principle is determined by two chaotic sequences. Then the rotated information is encoded by secure polar coding scheme. After the channel polarization achieved by the polar coding, we could identify the bit-channels providing good transmission conditions for legitimate users and the bit-channels with bad conditions for eavesdroppers. Simulations are performed over the visible light wiretap channel. The results demonstrate that compared with existing schemes, the proposed scheme can achieve better reliability and security even when the eavesdroppers have better channel conditions.
Manaka, Keisuke, Chen, Liyuan, Habuchi, Hiromasa, Kozawa, Yusuke.  2019.  Proposal of Equal-Weight (2, 2) Visual Secret Sharing Scheme on VN-CSK Illumination Light Communication. 2019 IEEE VTS Asia Pacific Wireless Communications Symposium (APWCS). :1–5.
Variable N-parallel code-shift-keying (VN-CSK) system has been proposed for solving the dimming control problem and the adjacent illumination light interference in illumination light communication. VN-CSK system only focuses on separating the light signal in the illumination light overlapping area. While, it is considerable to transmit a new data using the light overlapping. Visual secret sharing (VSS) scheme is a kind of secret sharing scheme, which distributes the secret data for security and restore by overlapping. It has high affinity to visible light communication. In this paper, a system combined with visible light communication and (2,2)-VSS scheme is proposed. In the proposed system, a modified pseudo orthogonal M-sequence is used that the occurrence probability of 0 and 1 of share is one-half in order to achieve a constant illuminance. In addition, this system use Modified Pseudo-Orthogonal M-sequence(MPOM) for ensuring the lighting function. The bit error rate performance of the proposed system is evaluated under the indoor visible light communication channel by simulation.
Tian, Dinghui, Zhang, Wensheng, Sun, Jian, Wang, Cheng-Xiang.  2019.  Physical-Layer Security of Visible Light Communications with Jamming. 2019 IEEE/CIC International Conference on Communications in China (ICCC). :512–517.
Visible light communication (VLC) is a burgeoning field in wireless communications as it considers illumination and communication simultaneously. The broadcast nature of VLC makes it necessary to consider the security of underlying transmissions. A physical-layer security (PLS) scheme by introducing jamming LEDs is considered in this paper. The secrecy rate of an indoor VLC system with multiple LEDs, one legitimate receiver, and multiple eavesdroppers is investigated. Three distributions of input signal are assumed, i.e., truncated generalized normal distribution (TGN), uniform distribution, and exponential distribution. The results show that jamming can improve the secrecy performance efficiently. This paper also demonstrates that when the numbers of LEDs transmitting information-bearing signal and jamming signal are equal, the average secrecy rate can be maximized.
2020-07-10
Koloveas, Paris, Chantzios, Thanasis, Tryfonopoulos, Christos, Skiadopoulos, Spiros.  2019.  A Crawler Architecture for Harvesting the Clear, Social, and Dark Web for IoT-Related Cyber-Threat Intelligence. 2019 IEEE World Congress on Services (SERVICES). 2642-939X:3—8.
The clear, social, and dark web have lately been identified as rich sources of valuable cyber-security information that -given the appropriate tools and methods-may be identified, crawled and subsequently leveraged to actionable cyber-threat intelligence. In this work, we focus on the information gathering task, and present a novel crawling architecture for transparently harvesting data from security websites in the clear web, security forums in the social web, and hacker forums/marketplaces in the dark web. The proposed architecture adopts a two-phase approach to data harvesting. Initially a machine learning-based crawler is used to direct the harvesting towards websites of interest, while in the second phase state-of-the-art statistical language modelling techniques are used to represent the harvested information in a latent low-dimensional feature space and rank it based on its potential relevance to the task at hand. The proposed architecture is realised using exclusively open-source tools, and a preliminary evaluation with crowdsourced results demonstrates its effectiveness.
2020-07-03
Viegas, P., Borges, D., Montezuma, P., Dinis, R., Silva, M. M..  2019.  Multi-beam Physical Security Scheme: Security Assessment and Impact of Array Impairments on Security and Quality of Service. 2019 PhotonIcs Electromagnetics Research Symposium - Spring (PIERS-Spring). :2368—2375.
Massive multiple-input multiple-output (mMIMO) with perfect channel state information (CSI) can lead array power gain increments proportional to the number of antennas. Despite this fact constrains on power amplification still exist due to envelope variations of high order constellation signals. These constrains can be overpassed by a transmitter with several amplification branches, with each one associated to a component signal that results from the decomposition of a multilevel constellation as a sum of several quasi constant envelope signals that are sent independently. When combined with antenna arrays at the end of each amplification branch the security improves due to the energy separation achieved by beamforming. However, to avoid distortion on the signal resulting from the combination of all components at channel level all the beams of signal components should be directed in same direction. In such conditions it is crucial to assess the impact of misalignments between beams associated to each user, which is the purpose of this work. The set of results presented here show the good tolerance against misalignments of these transmission structures.
2020-06-29
Giri, Nupur, Jaisinghani, Rahul, Kriplani, Rohit, Ramrakhyani, Tarun, Bhatia, Vinay.  2019.  Distributed Denial Of Service(DDoS) Mitigation in Software Defined Network using Blockchain. 2019 Third International conference on I-SMAC (IoT in Social, Mobile, Analytics and Cloud) (I-SMAC). :673–678.
A DDoS attack is a spiteful attempt to disrupt legitimate traffic to a server by overwhelming the target with a flood of requests from geographically dispersed systems. Today attackers prefer DDoS attack methods to disrupt target services as they generate GBs to TBs of random data to flood the target. In existing mitigation strategies, because of lack of resources and not having the flexibility to cope with attacks by themselves, they are not considered to be that effective. So effective DDoS mitigation techniques can be provided using emerging technologies such as blockchain and SDN(Software-Defined Networking). We propose an architecture where a smart contract is deployed in a private blockchain, which facilitates a collaborative DDoS mitigation architecture across multiple network domains. Blockchain application is used as an additional security service. With Blockchain, shared protection is enabled among all hosts. With help of smart contracts, rules are distributed among all hosts. In addition, SDN can effectively enable services and security policies dynamically. This mechanism provides ASes(Autonomous Systems) the possibility to deploy their own DPS(DDoS Prevention Service) and there is no need to transfer control of the network to the third party. This paper focuses on the challenges of protecting a hybridized enterprise from the ravages of rapidly evolving Distributed Denial of Service(DDoS) attack.
2020-06-19
Eziama, Elvin, Ahmed, Saneeha, Ahmed, Sabbir, Awin, Faroq, Tepe, Kemal.  2019.  Detection of Adversary Nodes in Machine-To-Machine Communication Using Machine Learning Based Trust Model. 2019 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT). :1—6.

Security challenges present in Machine-to-Machine Communication (M2M-C) and big data paradigm are fundamentally different from conventional network security challenges. In M2M-C paradigms, “Trust” is a vital constituent of security solutions that address security threats and for such solutions,it is important to quantify and evaluate the amount of trust in the information and its source. In this work, we focus on Machine Learning (ML) Based Trust (MLBT) evaluation model for detecting malicious activities in a vehicular Based M2M-C (VBM2M-C) network. In particular, we present an Entropy Based Feature Engineering (EBFE) coupled Extreme Gradient Boosting (XGBoost) model which is optimized with Binary Particle Swarm optimization technique. Based on three performance metrics, i.e., Accuracy Rate (AR), True Positive Rate (TPR), False Positive Rate (FPR), the effectiveness of the proposed method is evaluated in comparison to the state-of-the-art ensemble models, such as XGBoost and Random Forest. The simulation results demonstrates the superiority of the proposed model with approximately 10% improvement in accuracy, TPR and FPR, with reference to the attacker density of 30% compared with the start-of-the-art algorithms.

Shapiro, Jeffrey H., Boroson, Don M., Dixon, P. Ben, Grein, Matthew E., Hamilton, Scott A..  2019.  Quantum Low Probability of Intercept. 2019 Conference on Lasers and Electro-Optics (CLEO). :1—2.

Quantum low probability of intercept transmits ciphertext in a way that prevents an eavesdropper possessing the decryption key from recovering the plaintext. It is capable of Gbps communication rates on optical fiber over metropolitan-area distances.

Khandani, Amir K., Bateni, E..  2019.  A Practical, Provably Unbreakable Approach to Physical Layer Security. 2019 16th Canadian Workshop on Information Theory (CWIT). :1—6.

This article presents a practical approach for secure key exchange exploiting reciprocity in wireless transmission. The method relies on the reciprocal channel phase to mask points of a Phase Shift Keying (PSK) constellation. Masking is achieved by adding (modulo 2π) the measured reciprocal channel phase to the PSK constellation points carrying some of the key bits. As the channel phase is uniformly distributed in [0, 2π], knowing the sum of the two phases does not disclose any information about any of its two components. To enlarge the key size over a static or slow fading channel, the Radio Frequency (RF) propagation path is perturbed to create independent realizations of multi-path fading. Prior techniques have relied on quantizing the reciprocal channel state measured at the two ends and thereby suffer from information leakage in the process of key consolidation (ensuring the two ends have access to the same key). The proposed method does not suffer from such shortcomings as raw key bits can be equipped with Forward Error Correction (FEC) without affecting the masking (zero information leakage) property. To eavesdrop a phase value shared in this manner, the Eavesdropper (Eve) would require to solve a system of linear equations defined over angles, each equation corresponding to a possible measurement by the Eve. Channel perturbation is performed such that each new channel state creates an independent channel realization for the legitimate nodes, as well as for each of Eves antennas. As a result, regardless of the Eves Signal-to-Noise Ratio (SNR) and number of antennas, Eve will always face an under-determined system of equations. On the other hand, trying to solve any such under-determined system of linear equations in terms of an unknown phase will not reveal any useful information about the actual answer, meaning that the distribution of the answer remains uniform in [0, 2π].

2020-06-15
Cai, Peixiang, Zhang, Yu, Wang, Xuesi, Pan, Changyong.  2018.  Motion-Aware Clock Synchronization for Mobile Ad-Hoc Networks. 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall). :1–5.
Recently, mobile ad-hoc networks (MANET) have been widely used in several scenarios. Due to its generally high demands on clock synchronization accuracy, the conventional synchronization algorithms cannot be applied in many high-speed MANET applications. Hence, in this paper, a clock synchronization algorithm based on motion information such as the speed of nodes is proposed to eliminate the error of round-trip-time correction. Meanwhile, a simplified version of our algorithm is put forward to cope with some resource-constrained scenes. Our algorithm can perform well in most situations and effectively improve the clock synchronization accuracy with reasonable communication overhead, especially in high-speed scenes. Simulation results confirm the superior accuracy performance achieved by our algorithm.
Biradar, Shivleela, Sasi, Smitha.  2018.  Design and Implementation of Secure and Encoded Data Transmission Using Turbo Codes. 2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT). :1–7.
The general idea to achieve error detection and correction is to add some extra bit to an original message, in which the receiver can use to check the flexibility of the message which has been delivered, and to recover the noisy data. Turbo code is one of the forward error correction method, which is able to achieve the channel capacity, with nearer Shannon limit, encoding and decoding of text and images are performed. Methods and the working have been explained in this paper. The error has also introduced and detection and correction of errors have been achieved. Transmission will be secure it can secure the information by the theft.
Keleman, Levon, Matić, Danijel, Popović, Miroslav, Kaštelan, Ivan.  2019.  Secure firmware update in embedded systems. 2019 IEEE 9th International Conference on Consumer Electronics (ICCE-Berlin). :16–19.
Great numbers of embedded devices are performing safety critical operations, which means it is very important to keep them operating without interference. Update is the weak point that could be exploited by potential attackers to gain access to the system, sabotage it or to simply steal someone else's intellectual property. This paper presents an implementation of secure update process for embedded systems which prevents man-in-the-middle attacks. By using a combination of hash functions, symmetric and asymmetric encryption algorithms it demonstrates how to achieve integrity, authenticity and confidentiality of the update package that is sent to the target hardware. It covers implementation starting from key exchange, next explaining update package encryption process and then decryption on the target hardware. It does not go into a detail about specific encryption algorithms that could be used. It presents a generalized model for secure update that could be adjusted to specific needs.
2020-06-08
Boubakri, Wided, Abdallah, Walid, Boudriga, Noureddine.  2019.  Game-Based Attack Defense Model to Provide Security for Relay Selection in 5G Mobile Networks. 2019 IEEE Intl Conf on Parallel Distributed Processing with Applications, Big Data Cloud Computing, Sustainable Computing Communications, Social Computing Networking (ISPA/BDCloud/SocialCom/SustainCom). :160–167.
5G mobile networks promise universal communication environment and aims at providing higher bandwidth, increased communication and networking capabilities, and extensive signal coverage by using multiple communication technologies including Device-to-Device (D-to-D). This paradigm, will allow scalable and ubiquitous connectivity for large-scale mobile networks where a huge number of heterogeneous devices with limited resources will cooperate to enhance communication efficiency in terms of link reliability, spectral efficiency, system capacity, and transmission range. However, owing to its decentralized nature, cooperative D-to-D communication could be vulnerable to attacks initiated on relay nodes. Consequently, a source node has the interest to select the more protected relay to ensure the security of its traffic. Nevertheless, an improvement in the protection level has a counterpart cost that must be sustained by the device. To address this trade-off as well as the interaction between the attacker and the source device, we propose a dynamic game theoretic based approach to model and analyze this problem as a cost model. The utility function of the proposed non-cooperative game is based on the concepts of return on protection and return on attack which illustrate the gain of selecting a relay for transmitting a data packet by a source node and the reward of the attacker to perform an attack to compromise the transmitted data. Moreover, we discuss and analyze Nash equilibrium convergence of this attack-defense model and we propose an heuristic algorithm that can determine the equilibrium state in a limited number of running stages. Finally, we perform simulation work to show the effectiveness of the game model in assessing the behavior of the source node and the attacker and its ability to reach equilibrium within a finite number of steps.
2020-06-02
Krawec, Walter O..  2019.  Multi-Mediated Semi-Quantum Key Distribution. 2019 IEEE Globecom Workshops (GC Wkshps). :1—6.

A semi-quantum key distribution (SQKD) protocol allows two users A and B to establish a shared secret key that is secure against an all-powerful adversary E even when one of the users (e.g., B) is semi-quantum or classical in nature while the other is fully-quantum. A mediated SQKD protocol allows two semi-quantum users to establish a key with the help of an adversarial quantum server. We introduce the concept of a multi-mediated SQKD protocol where two (or more) adversarial quantum servers are used. We construct a new protocol in this model and show how it can withstand high levels of quantum noise, though at a cost to efficiency. We perform an information theoretic security analysis and, along the way, prove a general security result applicable to arbitrary MM-SQKD protocols. Finally, a comparison is made to previous (S)QKD protocols.

Gong, Shixun, Li, Na, Wu, Huici, Tao, Xiaofeng.  2019.  Cooperative Two-Key Generation in Source-Type Model With Partial-Trusted Helpers. 2019 IEEE/CIC International Conference on Communications in China (ICCC). :689—694.

This paper investigates the problem of generating two secret keys (SKs) simultaneously over a five-terminal system with terminals labelled as 1, 2, 3, 4 and 5. Each of terminal 2 and terminal 3 wishes to generate an SK with terminal 1 over a public channel wiretapped by a passive eavesdropper. Terminal 4 and terminal 5 respectively act as a trusted helper and an untrusted helper to assist the SK generation. All the terminals observe correlated source sequences from discrete memoryless sources (DMS) and can exchange information over a public channel with no rate constraint that the eavesdropper has access to. Based on the considered model, key capacity region is fully characterized and a source coding scheme that can achieve the capacity region is provided. Furthermore, expression for key leakage rate is obtained to analyze the security performance of the two generated keys.

Aliasgari, Malihe, Simeone, Osvaldo, Kliewer, Jörg.  2019.  Distributed and Private Coded Matrix Computation with Flexible Communication Load. 2019 IEEE International Symposium on Information Theory (ISIT). :1092—1096.

Tensor operations, such as matrix multiplication, are central to large-scale machine learning applications. These operations can be carried out on a distributed computing platform with a master server at the user side and multiple workers in the cloud operating in parallel. For distributed platforms, it has been recently shown that coding over the input data matrices can reduce the computational delay, yielding a tradeoff between recovery threshold and communication load. In this work, we impose an additional security constraint on the data matrices and assume that workers can collude to eavesdrop on the content of these data matrices. Specifically, we introduce a novel class of secure codes, referred to as secure generalized PolyDot codes, that generalizes previously published non-secure versions of these codes for matrix multiplication. These codes extend the state-of-the-art by allowing a flexible trade-off between recovery threshold and communication load for a fixed maximum number of colluding workers.

Kundu, M. K., Shabab, S., Badrudduza, A. S. M..  2019.  Information Theoretic Security over α-µ/α-µ Composite Multipath Fading Channel. 2019 IEEE International Conference on Telecommunications and Photonics (ICTP). :1—4.

Multipath fading as well as shadowing is liable for the leakage of confidential information from the wireless channels. In this paper a solution to this information leakage is proposed, where a source transmits signal through a α-μ/α-μ composite fading channel considering an eavesdropper is present in the system. Secrecy enhancement is investigated with the help of two fading parameters α and μ. To mitigate the impacts of shadowing a α-μ distribution is considered whose mean is another α-μ distribution which helps to moderate the effects multipath fading. The mathematical expressions of some secrecy matrices such as the probability of non-zero secrecy capacity and the secure outage probability are obtained in closed-form to analyze security of the wireless channel in light of the channel parameters. Finally, Monte-Carlo simulations are provided to justify the correctness of the derived expressions.

2020-06-01
Sivanesh, S., Sarma Dhulipala, V.R..  2019.  Comparitive Analysis of Blackhole and Rushing Attack in MANET. 2019 TEQIP III Sponsored International Conference on Microwave Integrated Circuits, Photonics and Wireless Networks (IMICPW). :495—499.

For the past few decades, mobile ad hoc networks (MANETs) have been a global trend in wireless networking technology. These kind of ad-hoc networks are infrastructure less, dynamic in topology and further doesn't have a centralized network administration which makes it easier for the intruders to launch several attacks on MANETs. In this paper, we have made a comparative analysis of the network layer attack by simulating rushing and black hole attack using NS-2 network simulator. For determining the most vulnerable attack we have considered packet delivery ratio, end to end delay and throughput as a evaluation metrices. Here, AODV routing protocol has been configured for data forwarding operations. From our Simulation result, it is evident that the black hole attack is more vulnerable when compared to the rushing attack.

Kapoor, Chavi.  2019.  Routing Table Management using Dynamic Information with Routing Around Connectivity Holes (RACH) for IoT Networks. 2019 International Conference on Automation, Computational and Technology Management (ICACTM). :174—177.

The internet of things (IoT) is the popular wireless network for data collection applications. The IoT networks are deployed in dense or sparse architectures, out of which the dense networks are vastly popular as these are capable of gathering the huge volumes of data. The collected data is analyzed using the historical or continuous analytical systems, which uses the back testing or time-series analytics to observe the desired patterns from the target data. The lost or bad interval data always carries the high probability to misguide the analysis reports. The data is lost due to a variety of reasons, out of which the most popular ones are associated with the node failures and connectivity holes, which occurs due to physical damage, software malfunctioning, blackhole/wormhole attacks, route poisoning, etc. In this paper, the work is carried on the new routing scheme for the IoTs to avoid the connectivity holes, which analyzes the activity of wireless nodes and takes the appropriate actions when required.

Pruthi, Vardaan, Mittal, Kanika, Sharma, Nikhil, Kaushik, Ila.  2019.  Network Layers Threats its Countermeasures in WSNs. 2019 International Conference on Computing, Communication, and Intelligent Systems (ICCCIS). :156—163.

WSN can be termed as a collection of dimensionally diffused nodes which are capable of surveilling and analyzing their surroundings. The sensors are delicate, transportable and small in size while being economical at the same time. However, the diffused nature of these networks also exposes them to a variety of security hazards. Hence, ensuring a reliable file exchange in these networks is not an easy job due to various security requirements that must be fulfilled. In this paper we concentrate mainly on network layer threats and their security countermeasures to overcome the scope of intruders to access the information without having any authentication on the network layer. Various network layer intrusions that are discussed here include Sinkhole Attack, Sybil Attack, Wormhole Attack, Selective Forwarding Attack, Blackhole Attack And Hello Flood Attack.