Mobile Sinks are very important in many wireless sensor networks applications for efficient accumulation of data, sensor reprogramming that is localized, and for distinguishing and revoking compromised sensors. This paper describes a three-tier general framework that permits to provide a platform for various applications that can improve safety and efficient group communication. One of them is multicasting networks. In existing system, Tiered Authentication scheme for Multicasting (TAM) is used for the multicast traffic in ad-hoc networks. Two tiered hierarchy combines the time and secret-information asymmetry to achieve the resource efficiency and scalability. In proposed system, an Asynchronous authentication scheme using shared key management is to resolve the most conflicting security requirements such as group authentication and conditional privacy.
Distributed networks, Network security, wireless sensor networks.
The wireless and mobile networks represent an increasingly important segment of networking research as a whole, driven by the rapid growth of portable computing, communication and embedded devices connected to the Internet. The advances in electronic technology have paved the way for the development of a new generation of wireless sensor networks (WSNs) consisting of a large number of low-power, low-cost sensor nodes that communicate wirelessly. mobile sinks (MSs) (or mobile soldiers, mobile sensor nodes) are essential components in the operation of many sensor network applications, including data collection in hazardous environments localized reprogramming, oceanographic data collection, and military navigation. Over the next 10-15 years, it is anticipated that significant qualitative changes to the Internet will be driven by the rapid proliferation of mobile and wireless devices, which may be expected to outnumber wired PC's as early as 2010. The potential impact of the future wireless Internet is very significant because the network combines the power of computation, search engines and databases in the background with the immediacy of information from mobile users and sensors in the foreground.
A Mobile Ad hoc Network consists of wireless Mobile Nodes (MNs) that cooperatively communicate with each other without the existence of fixed network infrastructure. Depending on different geographical topologies, the MNs are dynamically located and continuously changing their positions. The fast-changing characteristics in ad hoc networks make it difficult to discover routes between MNs. It becomes important to design efficient and reliable multi-hop routing protocols to discover, organize, and maintain the routes in ad hoc networks.
A cell phone is essentially a battery-powered microprocessor with one or more wireless transmitters and receivers optimized for voice I/O. Even a bare-bones model provides a keyboard, an LCD screen, and a general-purpose computing platform, typically supporting Java2 Mobile Edition (J2ME) or .NET Compact APIs. More sophisticated models provide a camera, 1MB-5GB of local storage, a full-color screen, multiple wireless interfaces, and even a QWERTY keypad.
Wireless communication is much more difficult to achieve than wired communication because the surrounding environment interacts with the signal, blocking signal paths and introducing noise and echoes. As a result wireless connections have a lower quality than wired connections: lower bandwidth, less connection stability, higher error rates, and, moreover, with a highly varying quality. These factors can in turn increase communication latency due to retransmissions, can give largely varying throughput, and incur high energy consumption. In this section, we discuss a set of protocol design issues related to the networking requirements of the representative wireless scenarios identified earlier.
Smart hospitals, battlefields and earthquake response systems are applicable sensor network systems. Such systems require a large geographic coverage. At the same time, a high density is required to work against the high failure rate of sensor nodes, the low confidence in individual sensor readings, the limited communication range and low capability of single sensor nodes. Due to these reasons, sensor networks are expected to scale up to thousands and millions of nodes, two orders of magnitude larger than traditional ad hoc networks.
Sensor networks are faulty networks where failures should be treated as normal phenomena. Unreliable nodes, constrained energy, high channel bit error ratio, interference and jamming, multi-path-fading, asymmetric channel and weak security make the communication highly unreliable. At same time, sensor networks are highly dynamic networks where network topologies are constantly changing due to a high rate of node failure, changes of power modes, and nodes' mobility.
THREE TIER SECURITY SCHEME
Three Tier Process
Recent advances in electronic technology have paved the way for the development of a new generation of wireless sensor networks (WSNs) consisting of a large number of low-power, low-cost sensor nodes that communicate wirelessly. However, the resource constraints of the sensors and their nature of communication over a wireless medium make data confidentiality and integrity a nontrivial task. Mobile sinks are the receiving stations of the message transmission. This mobile sinks are receiving the messages through the access points of the message transmission process. Sensors are the sender of the messages to the mobile sinks through the access points.
Fig 1: Three-tier security scheme in WSN with mobile sinks
This three-tier security schemes are used for the communication between many senders and receivers. This communication process is essential for group communication.
It protects the messages through the encryption and decryption techniques and provides the multi-level security for the group communication. The key management problem is an active research area in wireless sensor networks.
Sources of Challenges in Wireless Networks
There are many features of the wireless medium that distinguish it from other media. The wireless medium is a shared medium. This means that unlike wire line systems, where there exist dedicated physical connections between users, every user can essentially receive an attenuated version what other users are transmitting.
Wireless Medium Resources
Broadcasting Interference Fading Path-loss Mobilityâ€¦
Rate Delay Reliability Securityâ€¦
Distributed Processing of Local Information
Fig 2: Sources of challenges in analysis and design of wireless networks
In such a system, the manner of transmission is broadcast of the signal and there is interference in reception of a signal. Another property of a wireless channel is its random time- varying behavior due to the mobility of users and other objects, as well as obstacles in the environment.
More specifically, the channel to a given user might have poor conditions at some times and favorable conditions at other times. This is called the fading behavior of the channel. In many situations, multiple copies of the transmitted signal may be received with different delays and different strengths. This is referred to as "multipath fading" and can severely deteriorate the performance when the transmitted signals have shorter duration (e.g., broadband transmission). Conventionally, the goal is to combat the randomness introduced by the environment. For instance, the multi-user diversity gain in the downlink of cellular systems is based on this idea, i.e., in a system of many users with random quality of reception (fading), there exists one user with good quality of reception with very high probability.
The topology formed the network and then transmitted the information for managing the key values. The key management process managing the key by the intra and inter clustering techniques. Then only the key establishment process occurred by the hash functions of the key values. Using the hash function, the process of transmitting the information with the secret key is very easy. The analysis process is calculating the time delay and the bandwidth overhead.
The simulation work has been done with The Network Simulator ns-2, Version 2.29. In the simulation 50 nodes are randomly distributed within the network field of size 2400mx2400m. Ad hoc network topology is formed with the help of various nodes creation. Clusters are formed based on the location and their connectivity with other nodes.
Inter Cluster Techniques
Intra Cluster Techniques
Fig 3: Architectural Model
Each cluster is controlled by the cluster heads from them only messages are passed to another cluster. Source nodes are in connection with cluster heads.
In this paper use RSA based key generation. And then use of hashing technique for memory optimization. Then create one pair wise key and one shared key. After the creation of these keys, the authentication process will start for the intra and inter communication through the wireless sensor networks. Network Animator is presented information such as throughput, number packets on each link.
Group key management (Intra cluster)
Nodes get keys dynamically in the key distribution phase and then start to broadcast their geographic based. All nodes getting keys from the same leader form a group, as illustrated in the communication range of RSUs is 300 meter. The key was asymmetric based group key method in both Leader and member have a common key for sharing. This group key identifies the cluster head and provides the authentication
Shared key management (Inter cluster)
Leaders get keys dynamically in the key distribution phase and then start to broadcast their geographic condition messages. All leader nodes getting keys from the server form, as illustrated in the communication range of leader is 300 meter. If one cluster head has the key, it will provide the key for authentication for each cluster head. Then the leader shares the key between all cluster heads. The key was asymmetric based shared key method in each cluster heads have a common key for sharing.
Compare both the theoretical and simulation results under our protocol with those under the protocol in. Since the cooperative authentication protocol is of particularly importance in the high-load scenario, thus only focus on the highway scenario in this part. Assume six percent of the vehicles are malicious in our simulations. Malicious vehicles always send invalid RBM.
Operation in a network setup
Finding the optimal strategy for the nodes of a network in order to optimally perform a given task is very much an open problem. Consider the simple network, with only three nodes, in the above figure. The desired task is reliable communication from the source to the destination with the aid of the relay node. The relay node is connected to both the source and destination through communications channels. Even for this simple network, finding the optimal operation at each node for maximizing the rate of reliable communication is unsolved.
Fig 4: Simple network with one relay component (R), one source (S) and one destination (D)
The main difficulty in a network setup is the distributed nature of the information in the network. Each user has only access to local information and has to cooperate with other nodes in a distributed fashion to maximize the performance.
The above sources have raised many important and interesting challenges regarding the performance limits of different tasks such as communications and computation over networks. In addition, there are many design issues concerning the complexity and the robustness of the systems that should be addressed for a thorough understanding and efficient operation of wireless networked systems.
Security and Multicasting: a Complex Deal
The IP multicast model is attractive because it can scale to a large number of members. However, scalability is achieved due to the fact that no host identification information is maintained by the routers. Any host in a subnet can join a multicast group without its subnet router passing identification information about the host to other routers in the distribution tree. This simplicity which makes the strength of multicast routing, presents however, many vulnerabilities:
1.IP multicast does not support closed groups In fact, multicast addresses are publicly known: joining or leaving a group does not require specific permissions. Hence, any user can join a multicast group and receive messages sent to group.
2.There is no access control to a multicast group: An intruder can send data to the group without being a valid member, and disturbs the multicast session or eventually create bottlenecks in the network (Denial of Service attack).
3.Data sent to the group: It may transit via many unsecure channels. Thus, eavesdropping opportunities are more important.
SECURITY THREATS AND COUNTER MEASURES
Denial of Service
In the basic IP multicast model, any node can send data to a multicast session, and any node can become a member of any multicast session. It is clear that this model is vulnerable to Denial of Service (DoS) attacks, where fraudulent users join or send data to multicast sessions only to waste bandwidth or to overwhelm other group members with garbage data or malicious code. Solving these problems requires controlling the ability of hosts to send data or to join a multicast tree distribution. These are called respectively: sender and receiver access control.
Eavesdropping / Confidentiality
In unicast communication, two users can provide confidentiality by encrypting data with a shared key. In multicast communication, a group key is given to every authorized member. This group key is used by the sender as a symmetric key to encrypt the multicast traffic. This becomes complicated when group membership is dynamic (members join and leave continuously the multicast session). Research work in group key management aims to provide efficient re-keying schemes for dynamic membership groups.
Data Origin Authentication
Denial of service
Receiver/Sender Access Control
Scope of the Thesis
Fig 5: Multicast Security Threats and their Countermeasures
Masquerading / Data Origin Authentication
Data origin authentication is the ability of group members to verify the identity of the sender of a received packet. There has been work that aims to efficiently provide this level of authentication.
Leaking / Water marking
Encryption is generally used to safeguard content while it is being transmitted so that unauthorized persons cannot read the stream from the network, but this offers no protection after the intended receiver receives the data. There is no protection against unauthorized duplication and propagation by the intended receiver. Watermarking can provide protection in the form of theft deterrence.
Here TAM Tiered Authentication scheme for multicast session. It is used to authenticate the source and to prevent the messages from the intruders. To authenticate the message source one-way hash chains is used within the same cluster. The authentication code is appended to the message body. The authentication key is exposed after the message is delivered. Two tired security scheme for time and secret information asymmetry in order to achieve the scalability and resource efficiency and to extend the implementation with RSA 3 key generation techniques. With a public key (PKA) or asymmetric key algorithm, a pair of keys is used to achieve the scalability and resource efficiency. RSA encryption, supplies unique and stability technology advantages, presents an authentication system. The one-way hash chains algorithm in conjunction with RSA three key techniques.