Enterprise-Wide Knowledge Management Systems and their Usage in Essay

Enterprise-Wide Knowledge Management Systems and their Usage in Creating a Learning Organization - Essay Example Many organizations rely on the database Oracle to manage data collection and transfer, a system that houses data and stores it based on logical parameters in datafiles (Alapati, 2008). This system categorizes data uploaded through the file server and also facilitates data retrieval. Linux and Microsoft Windows software are two operating systems supported by Oracle’s interface systems. The business implementing enterprise-wide knowledge management systems require what is referred to as structured knowledge systems dedicated to particular internal knowledge. The knowledge consists of human resources documentation, research reports, white papers, presentations and various best practice templates and research. Semistructured knowledge systems utilize email programs and email data, rich digital media content, and organizational brochures. These are managed by Oracle or other similar databases and must be supplemented with retrieval systems to ensure that internal and external users can access the data successfully. ... The external interfaces, consisting of personal computers or mobile devices, generally access the ASP database which is routed internally to Oracle through the web server through various security systems such a firewalling. Thus, in order to engage in setting up an enterprise-wide KM system, there must be ongoing information technology support and expertise to ensure data integrity and end user profiling. All of these systems provide considerable value to the business in several ways. First, once the architecture is set up, it becomes easier to physically map the knowledge resources in the organization to assist workers in understanding how to retrieve real-time information from different divisions. It assists management in creating process maps and resource relevance in the form of diagrams that facilitates more effective knowledge transfer from division to division. Further, it adds value by improving time management (Dataware Technologies, 2010). Without such systems, individuals are forced to scan multiple databases or make contact with those who traditionally maintained tacit knowledge that is not easily transferrable to others. Now that there are adequate storage databases, experts with specialized skills can develop diagrams or best practice (or even instructional brochures) so that individuals without this specialized knowledge can learn about process or systems that drive business and innovation. It also adds value to businesses that maintain off-site support personnel who serves as account representatives or expert/technical support for various customers. With the enterprise-wide KM system, they are now able to access information with the touch of a button through their external interface without having to chase support team members in the

I Believe Essay Example for Free

I Believe Essay Traveling to â€Å"land of opportunities† for future studies is a dream of many people as standards and quality of education is the best in the world. I am one of those lucky people who wished to study in America and finally landed in United States for this purpose. But it was not an easy task as rules and regulation for obtaining a student’s visa is hard. But troubles do not end with getting a student visa as after coming to United States, one finds himself entangled in other difficult rules. I myself experienced all these difficulties and hardships before arrival and after arrival in United States. When I applied at the United States consulate in my native country, I had to produce certain security documents in addition to my I-20 Form (Admission letter from my institute), funding document and passport. Although these security documents were necessary to clear the security conditions but it took me many days to get these from local authorities. Additionally, I wanted to come to America thirty days prior to the start of my course date in order to accommodate myself in the American environment and learn the culture and values of Americans. But again it was not a simple thing as I have to get a visitor visa first and it was also required to register with Department of Homeland Security office upon my arrival in United States. After one month, before beginning any studies, I must obtain a change of classification through Form I-539 (application for Change of Nonimmigrant Status). As these rules were hard to understand and were harder to follw, so I decided to end this venture. I believe that these procedures are cumbersome and forces one not to apply for a visa thirty days prior to the corse start date. I also believe that student must come earlier (more than thirty days) to United States to get an acquintance with the local customs, traditions and environment. There is another condition for F-1 visa that students must be enrolled as a full-time student at the institution. But sometime Institute does offer long duration courses in Language Proficiency but does not give it full time course status to these courses. This creates a lot of problem in getting student visa and students in this case only gets visit visa. I think that Language courses must also be included in the category of full time courses or the Visa rule about these courses should be relaxed and a student visa should be issued for these. There is another part of the visa application process; an interview at the embassy consular section is required for visa applicants. I believe that this interview process is an extra thing as students waits a lot to be called for interview. Again a communication barrier is another problem because students can not convey the real information due to language inability. He can not understand the questions of the Visa Clearance Office in the right context. This results in the failure of getting a visa. The immigration rules related to medical check-up and vaccinations is another problem that students face. I myself have to undergo a lot of difficult procedures. I believe that vaccination is necessary and United States has the right to allow only the healthy person to enter in its territory but these procedures must be simplified. Another hard rule is related to employment. According to the F-1 rules, maximum of 20 hours/week is allowed while the studies are in progress whereas during annual break periods one can work up to 40 hours a week. I believe that students must be given more time so that they can earn enough to partially support their non-curricular activities. It does not mean that their studies should be sacrificed but they should be allowed according heir spare time. Students should use this money to visit various parts of America and to get knowledge of American culture and geography. Another employment rule is related to on-campus job. One can not take jobs outside the college or institute premises. I think that this regulation is unfair as only few jobs are available on the campus. Furthermore, every international student tries to get job on the premises. This makes the situation difficult. So it is not possible for every student to get a job on his/her own campus. I think that this rule should be relaxed and students should b allowed to work in the surroundings of the university or institute. Again after one year, students are allowed to work off-campus bit it needs the approval of the institute. I believe that this procedure again creates difficulties for the students. Although jobs in the local surroundings are not rare but they are processed so quickly that after getting an approval from institute, they remain no more available. Although I suffered from only a few of these hard rules but most of the prospective students become a victim of one or more of these rules. So I think that these rules should be altered in order to take care of the students’ needs. Government must take initiative to accommodate the students and their genuine requirements.

Security for Insider Attacks in Mobile Ad Hoc Networks

Security for Insider Attacks in Mobile Ad Hoc Networks Abstract Mobile ad hoc networks are collection of wireless mobile nodes forming a temporary network without the aid of any established infrastructure. Security issues are more paramount in such networks even more so than in wired networks. Despite the existence of well-known security mechanisms, additional vulnerabilities and features pertinent to this new networking paradigm might render the traditional solutions inapplicable. In particular these networks are extremely under threat to insider attacks especially packet dropping attacks. It is very difficult to detect such attacks because they comes in the category of attacks in mobile ad hoc networks in which the attacker nodes becomes the part of the network. In this research work we have proposed a two folded approach, to detect and then to isolate such nodes which become the part of the network to cause packet dropping attacks. First approach will detect the misbehavior of nodes and will identify the malicious activity in network, and then upon identification of nodes misbehavior in network other approach will isolate the malicious node from network. OMNET++ simulator is used to simulate and verify the proposed solution. Experimental results shows that E-SAODV (Enhanced Secure Ad hoc On Demand Distance Vector protocol) performs much better than conventional SAODV (Secure Ad hoc On Demand Distance Vector Protocol) Chapter 1 Introduction Overview Mobile Ad-hoc networks are a new paradigm of wireless communication for mobile hosts. As there is no fixed infrastructure such as base stations for mobile switching. Nodes within each others range communicate directly via wireless links while those which are far apart rely on other nodes to transmit messages. Node mobility causes frequent changes in topology. The wireless nature of communication and lack of any security infrastructure raises several security problems. The following flowchart depicts the working of any general ad-hoc network. Features of Mobile Ad hoc Networks Based on the characteristics, Mobile Ad hoc Networks has following main features. Because of the limited energy supply for the wireless nodes and the mobility of the nodes, the wireless links between mobile nodes in the Ad hoc Network are not consistent for the communication participants. Due to the continuous motion of nodes, the topology of the mobile ad hoc network changes constantly, the nodes can continuously move into and out of the radio range of the other nodes in the ad hoc network, and the routing information will be changing all the time because of the movement of the nodes. Lack of incorporation of security features in statically configured wireless routing protocol not meant for Ad hoc environments. Because the topology of the Ad hoc Networks is changing constantly, it is necessary for each pair of adjacent nodes to incorporate in the routing issue so as to prevent some kind of potential attacks that try to make use of vulnerabilities in the statically configured routing protocol. Mobile Ad hoc Network Routing Protocols Routing in Mobile Ad hoc Networks faces additional challenges when compared to routing in traditional wired networks with fixed infrastructure. There are several well-known protocols that have been specifically developed to cope with the limitations imposed by Ad hoc networking environments. The problem of routing in such environments is aggravated by limiting factors such as rapidly changing topologies, high power consumption, low bandwidth and high error rates [1]. Most of the existing routing protocols follow two different design approaches to confront the inherent characteristics of Ad hoc networks namely Proactive Routing Protocols, Reactive Routing Protocols. Proactive Routing Protocols Proactive ad hoc routing protocols maintain at all times routing information regarding the connectivity of every node to all other nodes that participate in the network. These protocols are also known as Table-driven Ad hoc Routing Protocols. These protocols allow every node to have a clear and consistent view of the network topology by propagating periodic updates [1]. Therefore, all nodes are able to make immediate decisions regarding the forwarding of a specific packet. Two main protocols that fall into the category of proactive routing protocols are Destination-Sequenced Distance-Vector (DSDV) protocol [2] and the Optimized Link State Routing (OLSR) protocol [3]. Reactive Routing Protocols An alternative approach to the one followed by Proactive Routing Protocols also known as source-initiated on-demand routing, is Reactive Routing Protocols. According to this approach a route is created only when the source node requires one to a specific destination. A route is acquired by the initiation of a route discovery function by the source node. The data packets transmitted while a route discovery is in process are buffered and are sent when the path is established. An established route is maintained as long as it is required through a route maintenance procedure. The Ad hoc On-demand Distance Vector (AODV) routing protocol [4], Temporally Ordered Routing Algorithm (TORA) [5] and the Dynamic Source Routing protocol [6] are examples of this category of protocols. Security issues in Mobile Ad hoc Routing Protocols Any routing protocol must encapsulate an essential set of security mechanisms. These are mechanisms that help prevent, detect, and respond to security attacks. We can classify these major security goals into five main categories, which need to be addressed in order to maintain a reliable and secure ad-hoc network environment. Confidentiality Confidentiality is the protection of any information from being exposed to unintended entities. In ad-hoc networks this is more difficult to achieve because intermediates nodes receive the packets for other recipients, so they can easily eavesdrop the information being routed. Availability Availability means that a node should maintain its ability to provide all the designed services regardless of the security state of it . This security criterion is challenged mainly during the denial-of-service attacks, in which all the nodes in the network can be the attack target and thus some selfish nodes make some of the network services unavailable, such as the routing protocol or the key management service. Authentication Authentication assures that an entity of concern or the origin of a communication is what it claims to be or from. Without which an attacker would impersonate a node, thus gaining unauthorized access to resource and sensitive information and interfering with operation of other nodes. Integrity Integrity guarantees the identity of the messages when they are transmitted. Integrity can be compromised through malicious and accidental altering. A message can be dropped, replayed or revised by an adversary with malicious goal, which is regarded as malicious altering while if the message is lost or its content is changed due to some failures, which may be transmission errors or hardware errors such as hard disk failure, then it is categorized as accidental altering. Non-Repudiation Non-repudiation ensures that sending and receiving parties can never deny their sending or receiving the message. In order to achieve the overall goal of Mobile Ad hoc Network security, above five mechanisms must be implemented in any ad-hoc networks so as to ensure the security of the transmissions along that network. Secure Ad hoc Routing As discussed earlier over the past decade, many Ad hoc routing protocols have been proposed in literature. Among them the most widely used are AODV (Ad hoc On Demand Distance Vector) [4] and DSR (Dynamic Source Routing) [2] which comes in the category of re-active routing protocols of Ad hoc Networks. All of these protocols have been studied extensively. But as there were no security considerations in the original design of these protocols, these protocols remain under threat from the attackers. The main assumption of these protocols was that all participating nodes do so in good faith and without maliciously disrupting the operation of the protocol. However the existence of malicious entities can not be disregarded in the systems especially the environment used for Ad hoc Networks. To overcome the security vulnerabilities in existing routing protocols, many security enhancements in these protocols have been proposed but unfortunately these secure Ad hoc Routing Protocols were either designed for a particular protocol or to address a specific problem operation of the protocol. For example SAODV (Secure Ad hoc On Demand Distance Vector Protocol) [7] was proposed to secure AODV (Ad hoc On Demand Distance Vector) protocol, Ariadne [10] was proposed to protect DSR (Dynamic Source Routing) protocol, ARAN [7] was proposed to protect the Ad hoc Routing in general while SEAD [8] was proposed to protect the DSDV (Destination Sequence Distance Vector Routing) protocol. The purpose of SAR [9] (Security Aware Routing) was also to protect the Routing in Ad hoc Networks. Problem definition Thus ongoing studies on MANETs pose many challenging research areas including MANETs security. Since MANETs are made up entirely of wireless mobile nodes, they are inherently more susceptible to security threats compared to fixed networks [11]. Access to wireless links is virtually impossible to control thus adverse security events such as eavesdropping, spoofing and denial of service attacks are more easily accomplished. These security risks must be reduced to an acceptable level while maintaining an acceptable Quality of Service and network performance. However, in order to work properly, the routing protocols in MANETs need trusted working environments, which are not always available. There may be situations in which the environment may be adversarial. For example some nodes may be selfish, malicious, or compromised by attackers. Most of the work done regarding network security in MANETs focuses on preventing attackers from entering the network through secure key distribution and secure neighbor discovery [10],[12]. But these schemes become ineffective when the malicious nodes have entered the network, or some nodes in the network have been compromised. Therefore, threats from compromised nodes inside the network are far more dangerous than the attacks from outside the network. Since these attacks are initiated from inside the network by the participating malicious nodes which behave well before they are compromised, it is very hard to detect these attacks. Keeping in view the security threats faced by MANETs we focus on Packet Dropping Attack which is a serious threat to Mobile Ad hoc Networks. Although many research efforts have been put on secure routing protocols but the attacks like packet dropping is not adequately addressed. We study the packet dropping attack in which a malicious node intentionally drops the packets they received. Unlike all previous researches which attempt to tolerate Packet Dropping Attacks, our work makes the first effort to detect the malicious activity and then identify the malicious or compromised nodes in the network. Research Objective The fundamental objective of this research is to discuss the security attacks faced by Mobile Ad hoc Networks specially insider attacks and to review the security in existing routing protocols especially secure routing protocols in MANETs. We particularly focus on packet dropping attack which is a serious threat to Mobile Ad hoc Networks. A novel security enhancement scheme to address packet dropping attack has been proposed. Thesis Organization Chapter 2 provides a brief introduction of security threats faced by Mobile Ad hoc Networks and secure routing to address these attacks. Chapter 3 discusses about the related work and flaws identified in the related work. Chapter 4 presents the possible solutions to address the packet dropping attack in Mobile Ad hoc Networks. Chapter 5 includes the implementation of proposed mechanisms and Results of the proposed mechanism and the thesis is concluded in Chapter 6. Chapter 2 Security Threats and Secure Ad hoc Routing Protocols Introduction This chapter includes the threats and types of attacks faced by Mobile Ad hoc Networks. Secure Ad hoc routing protocols like SAODV [7] (Secure Ad hoc On Demand Distance Vector), SAR [16] (Security Aware Routing), and ARAN [9] (Authenticated Routing for Ad hoc Networks) etc and how these protocols are still vulnerable to attacks, are discussed in this chapter. Types of attacks in MANETs There are numerous kinds of attacks in the mobile ad hoc networks, almost all of which can be classified into two types, External Attacks and Insider Attacks. External Attacks External Attacks are those attacks, in which the attacker aims to cause congestion, propagate fake routing information or disturb nodes from providing services. External attacks are similar to the normal attacks in the traditional wired networks such that the adversary is in the proximity but not a trusted node in the network, therefore, this type of attack can be prevented and detected by the security methods such as authentication or firewall, which are relatively conventional security solutions. Internal or Insider Attacks Due to the invasive nature and open network media in the mobile ad hoc network, internal also known as insider attacks are more dangerous than the external attacks because the compromised or malicious nodes are originally the legitimate users of the Ad hoc network, they can easily pass the authentication and get protection from the security mechanisms. As a result, the adversaries can make use of them to gain normal access to the services that should only be available to the authorized users in the network, and they can use the legal identity provided by the compromised nodes to conceal their malicious behaviors. Therefore, more attention should be paid to the internal attacks initiated by the malicious insider nodes when we consider the security issues in the mobile ad hoc networks. Internal or insider nodes when become part of the network can misuse the network in the following ways Packet Dropping A malicious node can attack at its level or at lower levels. Particularly in the context of Packet Dropping Attack, within a trust level, a malicious node or any other node which aims at saving its resources or intentionally launching a attack can successfully drop packets without being noticed and can get services from other nodes for forwarding its own packets. Node Isolation An internal malicious node can prevent nodes from communicating with any other node. Route Disruption A malicious node can break down an existing route or prevent a new route from being established. Route Invasion An inside attacker adds itself between two endpoints of a communication channel. Attacks based on modification A very simplest way for a malicious node to disturb the operations of an ad-hoc network is to perform an attack based on modification. The only task the malicious or compromised node needs to perform is to announce better routes than the ones presently existing. This kind of attack is based on the modification of the metric value for a route or by altering control message fields. There are various ways to perform this type of attacks; some of them are discussed below Altering the Hop Count This attack is more specific to the AODV [4] protocol wherein the optimum path is chosen by the hop count metric. A malicious node can disturb the network by announcing the smallest hop count value to reach the compromised node. In general, an attacker would use a value zero to ensure to the smallest hop count. Changing the Route Sequence Number When a node decides the optimum path to take through a network, the node always relies on a metric of values, such as hop count delays etc. The smaller that value, the more optimum the path. Hence, a simple way to attack a network is to change this value with a smaller number than the last better value. Altering Routing Information This type of attack leads network toward Denial of Service (DoS) attack. For example in a situation where a node M wants to communicate with node S. At node M the routing path in the header would be M-N-O-P-Q-R-S. If N is a compromised node, it can alter this routing detail to M-N-O-P. But since there exists no direct route from O to P, P will drop the packet. Thus, A will never be able to access any service from P. This situation leads the network towards a DoS attack. Impersonation Attacks Impersonation is also known as spoofing. In this type of attack the malicious node hides its IP address or MAC address and uses the addresses of other nodes present in the network. Since current ad-hoc routing protocols like AODV [4] and DSR [6] do not authenticate source IP address. By exploiting this situation a malicious node can launch variety of attacks using spoofing. For example in a situation where an attacker creates loops in the network to isolate a node from the remainder of the network, the attacker needs to spoof the IP address of the node he wants to isolate from the network and then announce new route to the others nodes. By doing this, he can easily modify the network topology as he wants. Fabrication Attacks Fabrication attacks can be classified into three main categories. Detection is very difficult in all of these three cases. Routing table poisoning Routing protocols maintain tables which hold information regarding routes of the network. In routing table poisoning attacks the malicious nodes generate and send fabricated signaling traffic, or modify legitimate messages from other nodes, in order to create false entries in the tables of the participating nodes. For example, an attacker can send routing updates that do not correspond to actual changes in the topology of the ad hoc network. Routing table poisoning attacks can result in selection of non-optimal routes, creation of routing loops and bottlenecks. Route Cache Poisoning This type of attack falls in the category of passive attacks that can occur especially in DSR [6] due to the promiscuous mode of updating routing tables. This type of situation arises when information stored in routing tables is deleted, altered or injected with false information. A node overhearing any packet may add the routing information contained in that packets header to its own route cache, even if that node is not on the path from source to destination. The vulnerability of this system is that an attacker could easily exploit this method of learning routes and poison route caches by broadcast a message with a spoofed IP address to other nodes. When they receive this message, the nodes would add this new route to their cache and would now communicate using the route to reach the malicious node. Rote Error Messages fabrication This attack is very common in AODV [4] and DSR [6], because when nodes move these two protocols use path maintenance to recover the optimum path. The weakness of this architecture is that whenever a node moves, the closest node sends an error message to the other nodes so as to inform them that a route is no longer accessible. If an attacker can cause a DoS attack by spoofing any node and sending error messages to the all other nodes. As a result malicious node can separate any node quite easily. Eavesdropping Eavesdropping is another kind of attack that usually happens in the mobile ad hoc networks. The goal of eavesdropping is to obtain some confidential information that should be kept secret during the communication. This information may include the location, public key, private key or even passwords of the nodes. Because such data are very important to the security state of the nodes, they should be kept away from the unauthorized access. Secure Ad hoc Routing Protocols Many solutions have been proposed for secure routing in ad hoc networks, in order to offer protection against the attacks discussed earlier. These proposed solutions are either completely new stand-alone protocols, or in some cases incorporations of security mechanisms into existing ones (like DSR [6] and AODV [4]). In order to analyze the proposed solutions and how they are still vulnerable to attacks we classified them into two main categories based on asymmetric cryptography and symmetric cryptography. Asymmetric Cryptographic Solution Protocols that use asymmetric cryptography to secure routing in mobile ad hoc networks require the existence of a universally trusted third party. This trusted third party can be either online or offline. The trusted third party issues certificates that bind a nodes public key with a nodes persistent identifier. Authenticated Routing for Ad hoc Networks ARAN [9] falls in this category of secure Ad hoc routing protocols; many of the other protocols presented in other categories that use asymmetric cryptography operate in a similar manner and have similar requirements. Authenticated Routing for Ad hoc Networks ARAN The Authenticated Routing for Ad hoc Networks (ARAN) proposed in [9] is a standalone solution for secure routing in ad hoc networking environments. ARAN use digital certificates and can successfully operate in the managed open scenario where no infrastructure is pre-deployed. The basic mechanism used in ARAN is certification that is achieved through the existence of a trusted certification authority (CA). All nodes are supposed to know their public key from the certification authority and also the public key of server. Prior to entering into the network, each node has to apply for a certificate that is signed by the certificate server. ARAN accomplishes the discovery of routes by a broadcast message from source node which is replied in a unicast manner. This route discovery of the ARAN protocol begins with a node broadcasting to its neighbors a route discovery packet (RDP). The RDP includes the certificate of the initiating node, a nonce, a timestamp and the address of the destinatio n node. Furthermore, the initiating node signs the RDP. Each node validates the signature with the certificate, updates its routing table with the neighbor from which it received the RDP, signs it, and forwards it to its neighbors after removing the certificate and the signature of the previous node (but not the initiators signature and certificate). The signature prevents malicious nodes from injecting arbitrary route discovery packets that alter routes or form loops [13]. The destination node eventually receives the RDP and replies with a reply packet (REP). The REP contains the address of the source node, the destinations certificate, a nonce, and the associated timestamp. The destination node signs the REP before transmitting it. The REP is forwarded back to the initiating node by a process similar to the one described for the route discovery, except that the REP is unicasted along the reverse path. The source node is able to verify that the destination node sent the REP by chec king the nonce and the signature. Figure 2 illustrates the process of route discovery in ARAN. All messages are authenticated at each hop from source to destination as well as on the reverse path. Due to heavy computation involved with the certificates, ARAN is vulnerable to many attacks e.g. DOS attacks. In situation when there are no malicious nodes in the network the load involved in the routing process force the legitimate nodes to drop the packets in order to save their resources. Symmetric Cryptography Solutions Symmetric cryptographic solutions rely solely on symmetric cryptography to secure the function of routing in wireless ad hoc networks. The mechanisms utilized is hash functions and hash chains. A one-way hash function is a function that takes an input of arbitrary length and returns an output of fixed length [14]. As hash functions are especially lightweight when compared to other symmetric and asymmetric cryptographic operations, they have been extensively used in the context of securing ad hoc routing. Secure Ad hoc On-demand Distance Vector Protocol (SAODV) The Secure Ad hoc On Demand Distance Vector (SAODV) [7] addresses the problem of securing a MANET network. SAODV is an extension of AODV[4] routing protocol that can be used to protect the route discovery mechanism by providing security features like authentication, integrity and non-repudiation. It uses digital signatures to authenticate the non-mutable fields of the message, and hash chains to secure the hop count information (the only mutable field in message) in both RREQ and RREP messages. The SAODV scheme is based on the assumption that each node possesses certified public keys of all network nodes . In order to facilitate the transmission of the information required for the security mechanisms, SAODV defines extensions to the standard AODV message format. These SAODV extensions consist of the following fields. The hash function field identifies the one-way hash function that is used. The field max hop count is a counter that specifies the maximum number of nodes a packet is al lowed to go through. The top hash field is the result of the application of the hash function max hop count times to a randomly generated number, and finally the field hash is this random number. When a node transmits a route request or a route reply AODV packet it sets the max hop count field equal to the time to live (TTL) field from the IP header, generates a random number and sets the hash field equal to it, and applies the hash function specified by the corresponding field max hop count times to the random number, storing the calculated result to the top hash field. Moreover, the node digitally signs all fields of the message, except the hop count field from the AODV header and the hash field from the SAODV extension header. An intermediate node that receives a route request or a route reply must verify the integrity of the message and the hop count AODV [4] field. The integrity requirement is accomplished by verifying the digital signature. The hop count field is verified by comparing the result of the application of the hash function max hop count minus hop count times to the hash field with the value of the top hash field. Before the packet is re-broadcasted by the in termediate node the value of the hash field is replaced by the result of the calculation of the one-way hash of the field itself in order to account for the new hop. In SAODV route error messages (RERR) that are generated by nodes that inform their neighbors that they are not going to be able to route messages to specific destinations are secured using digital signatures. A node that generates or forwards a route error message cryptographically signs the whole message, except the destination sequence numbers. Although SAODV provides reasonable security to MANETs routing, but it is still vulnerable to distance fraud attack [15] in which the forwarding node fails to increment the route metric because in SAODV there is no enforcement to do so. Further there is no method to detect the malicious nodes and DOS attacks because in SAODV it is assumed that DOS attacks are restricted to physical layer, but this assumption failed when colluding malicious nodes drop packets during the route discovery process. Security Aware Routing (SAR) SAR [16] (Security Aware Routing) is an extension to existing on demand routing protocols and used where nodes are grouped on the basis of trust level. In SAR each node has different security level which assigns them different trust levels. Two nodes can only communicate with each other if they have equal or greater trust values. If a node has lower security level it simply discards the packet. In case there is no node in the network with the desired level then communication cannot take place or we can say that, that particular packet cant be forwarded unless its security level is lowered. By exploiting this condition a malicious node can attack at its level or at lower levels. Particularly in the context of Packet Dropping Attack, within a trust level, a malicious node or any other node which aims at saving its resources or intentionally launching a attack can successfully drop packets without being noticed and can get services from other nodes for forwarding its own packets. SAR al so fails in the situations of secure routing in general because it only focuses on the situations in which certain groups are assumed to be trustworthy. Conclusion From the above discussion, we observe that all Secure Ad hoc routing protocols are still vulnerable to many attacks. Although proposed techniques provide security against external attacks, insider attacks are still an open issue in MANETs. Chapter 3 Literature Review Introduction Many solutions have been proposed to prevent selfishness in MANETs. The main goal of all the schemes proposed in the literature is to make decisions regarding trustworthy entities and to encourage behavior that leads to increasing trust. In this section we discuss some of the solutions presented in the literature in order to detect the malicious nodes in the network in context of packet dropping attack. Watchdog and Pathrater In [17] Marti el al, proposed a mechanism called as watchdog and pathrater on DSR[6] to detect the misbehavior of nodes in MANETs. Nodes in this scheme operate in a promiscuous mode. The watchdog monitors one hop neighbor by overhearing the medium to check whether the next neighbor forwards the packet or not. It also maintains a buffer of recently sent packets. If a data packet remains in the buffer too long, the watchdog declares the next hop neighbor to be misbehaving. Every node that participates in the ad hoc network employs the watchdog functionality in order to verify that its neighbors correctly forward packets. When a node transmits a packet to the next node in the path, it tries to promiscuously listen if the next node will also transmit it. Furthermore, if there is no link encryption utilized in the network, the listening node can also verify that the next node did not modify the packet before transmitting it . The watchdog of a node maintains copies of recently forwarded p ackets and compares them with the packet transmissions overheard by the neighboring nodes. Positive comparisons result in the deletion of the buffered packet and the freeing of the related memory. If a node that was supposed to forward a packet fails to do so within a certain timeout period, the watchdog of an overhearing node increments a failure rating for the specific node. This effectively means that every node in the ad hoc network maintains a rating assessing the reliability of every other node that it can overhear packet transmissions from. A node is identified as misbehaving when the failure rating exceeds a certain threshold bandwidth. The source node of the route that contains the offending node is notified by a message send by the identifying watchdog. As the authors of the scheme note, the main problem with this approach is its vulnerability to blackmail attacks. The pathrater selects the path with the highest metric when there are multiple paths for the same destination node. The algorithm followed by the pathrater mechanism initially assigns a rating of 1.0 to itself and 0.5 to each node that it knows through the route discovery function. The nodes that participate on the active paths have their ratings increased by 0.01 at periodic intervals of 200 milliseconds to a maximum rating of 0.8. A rating is decremented by 0.05 when a link breakage is Security for Insider Attacks in Mobile Ad Hoc Networks Security for Insider Attacks in Mobile Ad Hoc Networks Abstract Mobile ad hoc networks are collection of wireless mobile nodes forming a temporary network without the aid of any established infrastructure. Security issues are more paramount in such networks even more so than in wired networks. Despite the existence of well-known security mechanisms, additional vulnerabilities and features pertinent to this new networking paradigm might render the traditional solutions inapplicable. In particular these networks are extremely under threat to insider attacks especially packet dropping attacks. It is very difficult to detect such attacks because they comes in the category of attacks in mobile ad hoc networks in which the attacker nodes becomes the part of the network. In this research work we have proposed a two folded approach, to detect and then to isolate such nodes which become the part of the network to cause packet dropping attacks. First approach will detect the misbehavior of nodes and will identify the malicious activity in network, and then upon identification of nodes misbehavior in network other approach will isolate the malicious node from network. OMNET++ simulator is used to simulate and verify the proposed solution. Experimental results shows that E-SAODV (Enhanced Secure Ad hoc On Demand Distance Vector protocol) performs much better than conventional SAODV (Secure Ad hoc On Demand Distance Vector Protocol) Chapter 1 Introduction Overview Mobile Ad-hoc networks are a new paradigm of wireless communication for mobile hosts. As there is no fixed infrastructure such as base stations for mobile switching. Nodes within each others range communicate directly via wireless links while those which are far apart rely on other nodes to transmit messages. Node mobility causes frequent changes in topology. The wireless nature of communication and lack of any security infrastructure raises several security problems. The following flowchart depicts the working of any general ad-hoc network. Features of Mobile Ad hoc Networks Based on the characteristics, Mobile Ad hoc Networks has following main features. Because of the limited energy supply for the wireless nodes and the mobility of the nodes, the wireless links between mobile nodes in the Ad hoc Network are not consistent for the communication participants. Due to the continuous motion of nodes, the topology of the mobile ad hoc network changes constantly, the nodes can continuously move into and out of the radio range of the other nodes in the ad hoc network, and the routing information will be changing all the time because of the movement of the nodes. Lack of incorporation of security features in statically configured wireless routing protocol not meant for Ad hoc environments. Because the topology of the Ad hoc Networks is changing constantly, it is necessary for each pair of adjacent nodes to incorporate in the routing issue so as to prevent some kind of potential attacks that try to make use of vulnerabilities in the statically configured routing protocol. Mobile Ad hoc Network Routing Protocols Routing in Mobile Ad hoc Networks faces additional challenges when compared to routing in traditional wired networks with fixed infrastructure. There are several well-known protocols that have been specifically developed to cope with the limitations imposed by Ad hoc networking environments. The problem of routing in such environments is aggravated by limiting factors such as rapidly changing topologies, high power consumption, low bandwidth and high error rates [1]. Most of the existing routing protocols follow two different design approaches to confront the inherent characteristics of Ad hoc networks namely Proactive Routing Protocols, Reactive Routing Protocols. Proactive Routing Protocols Proactive ad hoc routing protocols maintain at all times routing information regarding the connectivity of every node to all other nodes that participate in the network. These protocols are also known as Table-driven Ad hoc Routing Protocols. These protocols allow every node to have a clear and consistent view of the network topology by propagating periodic updates [1]. Therefore, all nodes are able to make immediate decisions regarding the forwarding of a specific packet. Two main protocols that fall into the category of proactive routing protocols are Destination-Sequenced Distance-Vector (DSDV) protocol [2] and the Optimized Link State Routing (OLSR) protocol [3]. Reactive Routing Protocols An alternative approach to the one followed by Proactive Routing Protocols also known as source-initiated on-demand routing, is Reactive Routing Protocols. According to this approach a route is created only when the source node requires one to a specific destination. A route is acquired by the initiation of a route discovery function by the source node. The data packets transmitted while a route discovery is in process are buffered and are sent when the path is established. An established route is maintained as long as it is required through a route maintenance procedure. The Ad hoc On-demand Distance Vector (AODV) routing protocol [4], Temporally Ordered Routing Algorithm (TORA) [5] and the Dynamic Source Routing protocol [6] are examples of this category of protocols. Security issues in Mobile Ad hoc Routing Protocols Any routing protocol must encapsulate an essential set of security mechanisms. These are mechanisms that help prevent, detect, and respond to security attacks. We can classify these major security goals into five main categories, which need to be addressed in order to maintain a reliable and secure ad-hoc network environment. Confidentiality Confidentiality is the protection of any information from being exposed to unintended entities. In ad-hoc networks this is more difficult to achieve because intermediates nodes receive the packets for other recipients, so they can easily eavesdrop the information being routed. Availability Availability means that a node should maintain its ability to provide all the designed services regardless of the security state of it . This security criterion is challenged mainly during the denial-of-service attacks, in which all the nodes in the network can be the attack target and thus some selfish nodes make some of the network services unavailable, such as the routing protocol or the key management service. Authentication Authentication assures that an entity of concern or the origin of a communication is what it claims to be or from. Without which an attacker would impersonate a node, thus gaining unauthorized access to resource and sensitive information and interfering with operation of other nodes. Integrity Integrity guarantees the identity of the messages when they are transmitted. Integrity can be compromised through malicious and accidental altering. A message can be dropped, replayed or revised by an adversary with malicious goal, which is regarded as malicious altering while if the message is lost or its content is changed due to some failures, which may be transmission errors or hardware errors such as hard disk failure, then it is categorized as accidental altering. Non-Repudiation Non-repudiation ensures that sending and receiving parties can never deny their sending or receiving the message. In order to achieve the overall goal of Mobile Ad hoc Network security, above five mechanisms must be implemented in any ad-hoc networks so as to ensure the security of the transmissions along that network. Secure Ad hoc Routing As discussed earlier over the past decade, many Ad hoc routing protocols have been proposed in literature. Among them the most widely used are AODV (Ad hoc On Demand Distance Vector) [4] and DSR (Dynamic Source Routing) [2] which comes in the category of re-active routing protocols of Ad hoc Networks. All of these protocols have been studied extensively. But as there were no security considerations in the original design of these protocols, these protocols remain under threat from the attackers. The main assumption of these protocols was that all participating nodes do so in good faith and without maliciously disrupting the operation of the protocol. However the existence of malicious entities can not be disregarded in the systems especially the environment used for Ad hoc Networks. To overcome the security vulnerabilities in existing routing protocols, many security enhancements in these protocols have been proposed but unfortunately these secure Ad hoc Routing Protocols were either designed for a particular protocol or to address a specific problem operation of the protocol. For example SAODV (Secure Ad hoc On Demand Distance Vector Protocol) [7] was proposed to secure AODV (Ad hoc On Demand Distance Vector) protocol, Ariadne [10] was proposed to protect DSR (Dynamic Source Routing) protocol, ARAN [7] was proposed to protect the Ad hoc Routing in general while SEAD [8] was proposed to protect the DSDV (Destination Sequence Distance Vector Routing) protocol. The purpose of SAR [9] (Security Aware Routing) was also to protect the Routing in Ad hoc Networks. Problem definition Thus ongoing studies on MANETs pose many challenging research areas including MANETs security. Since MANETs are made up entirely of wireless mobile nodes, they are inherently more susceptible to security threats compared to fixed networks [11]. Access to wireless links is virtually impossible to control thus adverse security events such as eavesdropping, spoofing and denial of service attacks are more easily accomplished. These security risks must be reduced to an acceptable level while maintaining an acceptable Quality of Service and network performance. However, in order to work properly, the routing protocols in MANETs need trusted working environments, which are not always available. There may be situations in which the environment may be adversarial. For example some nodes may be selfish, malicious, or compromised by attackers. Most of the work done regarding network security in MANETs focuses on preventing attackers from entering the network through secure key distribution and secure neighbor discovery [10],[12]. But these schemes become ineffective when the malicious nodes have entered the network, or some nodes in the network have been compromised. Therefore, threats from compromised nodes inside the network are far more dangerous than the attacks from outside the network. Since these attacks are initiated from inside the network by the participating malicious nodes which behave well before they are compromised, it is very hard to detect these attacks. Keeping in view the security threats faced by MANETs we focus on Packet Dropping Attack which is a serious threat to Mobile Ad hoc Networks. Although many research efforts have been put on secure routing protocols but the attacks like packet dropping is not adequately addressed. We study the packet dropping attack in which a malicious node intentionally drops the packets they received. Unlike all previous researches which attempt to tolerate Packet Dropping Attacks, our work makes the first effort to detect the malicious activity and then identify the malicious or compromised nodes in the network. Research Objective The fundamental objective of this research is to discuss the security attacks faced by Mobile Ad hoc Networks specially insider attacks and to review the security in existing routing protocols especially secure routing protocols in MANETs. We particularly focus on packet dropping attack which is a serious threat to Mobile Ad hoc Networks. A novel security enhancement scheme to address packet dropping attack has been proposed. Thesis Organization Chapter 2 provides a brief introduction of security threats faced by Mobile Ad hoc Networks and secure routing to address these attacks. Chapter 3 discusses about the related work and flaws identified in the related work. Chapter 4 presents the possible solutions to address the packet dropping attack in Mobile Ad hoc Networks. Chapter 5 includes the implementation of proposed mechanisms and Results of the proposed mechanism and the thesis is concluded in Chapter 6. Chapter 2 Security Threats and Secure Ad hoc Routing Protocols Introduction This chapter includes the threats and types of attacks faced by Mobile Ad hoc Networks. Secure Ad hoc routing protocols like SAODV [7] (Secure Ad hoc On Demand Distance Vector), SAR [16] (Security Aware Routing), and ARAN [9] (Authenticated Routing for Ad hoc Networks) etc and how these protocols are still vulnerable to attacks, are discussed in this chapter. Types of attacks in MANETs There are numerous kinds of attacks in the mobile ad hoc networks, almost all of which can be classified into two types, External Attacks and Insider Attacks. External Attacks External Attacks are those attacks, in which the attacker aims to cause congestion, propagate fake routing information or disturb nodes from providing services. External attacks are similar to the normal attacks in the traditional wired networks such that the adversary is in the proximity but not a trusted node in the network, therefore, this type of attack can be prevented and detected by the security methods such as authentication or firewall, which are relatively conventional security solutions. Internal or Insider Attacks Due to the invasive nature and open network media in the mobile ad hoc network, internal also known as insider attacks are more dangerous than the external attacks because the compromised or malicious nodes are originally the legitimate users of the Ad hoc network, they can easily pass the authentication and get protection from the security mechanisms. As a result, the adversaries can make use of them to gain normal access to the services that should only be available to the authorized users in the network, and they can use the legal identity provided by the compromised nodes to conceal their malicious behaviors. Therefore, more attention should be paid to the internal attacks initiated by the malicious insider nodes when we consider the security issues in the mobile ad hoc networks. Internal or insider nodes when become part of the network can misuse the network in the following ways Packet Dropping A malicious node can attack at its level or at lower levels. Particularly in the context of Packet Dropping Attack, within a trust level, a malicious node or any other node which aims at saving its resources or intentionally launching a attack can successfully drop packets without being noticed and can get services from other nodes for forwarding its own packets. Node Isolation An internal malicious node can prevent nodes from communicating with any other node. Route Disruption A malicious node can break down an existing route or prevent a new route from being established. Route Invasion An inside attacker adds itself between two endpoints of a communication channel. Attacks based on modification A very simplest way for a malicious node to disturb the operations of an ad-hoc network is to perform an attack based on modification. The only task the malicious or compromised node needs to perform is to announce better routes than the ones presently existing. This kind of attack is based on the modification of the metric value for a route or by altering control message fields. There are various ways to perform this type of attacks; some of them are discussed below Altering the Hop Count This attack is more specific to the AODV [4] protocol wherein the optimum path is chosen by the hop count metric. A malicious node can disturb the network by announcing the smallest hop count value to reach the compromised node. In general, an attacker would use a value zero to ensure to the smallest hop count. Changing the Route Sequence Number When a node decides the optimum path to take through a network, the node always relies on a metric of values, such as hop count delays etc. The smaller that value, the more optimum the path. Hence, a simple way to attack a network is to change this value with a smaller number than the last better value. Altering Routing Information This type of attack leads network toward Denial of Service (DoS) attack. For example in a situation where a node M wants to communicate with node S. At node M the routing path in the header would be M-N-O-P-Q-R-S. If N is a compromised node, it can alter this routing detail to M-N-O-P. But since there exists no direct route from O to P, P will drop the packet. Thus, A will never be able to access any service from P. This situation leads the network towards a DoS attack. Impersonation Attacks Impersonation is also known as spoofing. In this type of attack the malicious node hides its IP address or MAC address and uses the addresses of other nodes present in the network. Since current ad-hoc routing protocols like AODV [4] and DSR [6] do not authenticate source IP address. By exploiting this situation a malicious node can launch variety of attacks using spoofing. For example in a situation where an attacker creates loops in the network to isolate a node from the remainder of the network, the attacker needs to spoof the IP address of the node he wants to isolate from the network and then announce new route to the others nodes. By doing this, he can easily modify the network topology as he wants. Fabrication Attacks Fabrication attacks can be classified into three main categories. Detection is very difficult in all of these three cases. Routing table poisoning Routing protocols maintain tables which hold information regarding routes of the network. In routing table poisoning attacks the malicious nodes generate and send fabricated signaling traffic, or modify legitimate messages from other nodes, in order to create false entries in the tables of the participating nodes. For example, an attacker can send routing updates that do not correspond to actual changes in the topology of the ad hoc network. Routing table poisoning attacks can result in selection of non-optimal routes, creation of routing loops and bottlenecks. Route Cache Poisoning This type of attack falls in the category of passive attacks that can occur especially in DSR [6] due to the promiscuous mode of updating routing tables. This type of situation arises when information stored in routing tables is deleted, altered or injected with false information. A node overhearing any packet may add the routing information contained in that packets header to its own route cache, even if that node is not on the path from source to destination. The vulnerability of this system is that an attacker could easily exploit this method of learning routes and poison route caches by broadcast a message with a spoofed IP address to other nodes. When they receive this message, the nodes would add this new route to their cache and would now communicate using the route to reach the malicious node. Rote Error Messages fabrication This attack is very common in AODV [4] and DSR [6], because when nodes move these two protocols use path maintenance to recover the optimum path. The weakness of this architecture is that whenever a node moves, the closest node sends an error message to the other nodes so as to inform them that a route is no longer accessible. If an attacker can cause a DoS attack by spoofing any node and sending error messages to the all other nodes. As a result malicious node can separate any node quite easily. Eavesdropping Eavesdropping is another kind of attack that usually happens in the mobile ad hoc networks. The goal of eavesdropping is to obtain some confidential information that should be kept secret during the communication. This information may include the location, public key, private key or even passwords of the nodes. Because such data are very important to the security state of the nodes, they should be kept away from the unauthorized access. Secure Ad hoc Routing Protocols Many solutions have been proposed for secure routing in ad hoc networks, in order to offer protection against the attacks discussed earlier. These proposed solutions are either completely new stand-alone protocols, or in some cases incorporations of security mechanisms into existing ones (like DSR [6] and AODV [4]). In order to analyze the proposed solutions and how they are still vulnerable to attacks we classified them into two main categories based on asymmetric cryptography and symmetric cryptography. Asymmetric Cryptographic Solution Protocols that use asymmetric cryptography to secure routing in mobile ad hoc networks require the existence of a universally trusted third party. This trusted third party can be either online or offline. The trusted third party issues certificates that bind a nodes public key with a nodes persistent identifier. Authenticated Routing for Ad hoc Networks ARAN [9] falls in this category of secure Ad hoc routing protocols; many of the other protocols presented in other categories that use asymmetric cryptography operate in a similar manner and have similar requirements. Authenticated Routing for Ad hoc Networks ARAN The Authenticated Routing for Ad hoc Networks (ARAN) proposed in [9] is a standalone solution for secure routing in ad hoc networking environments. ARAN use digital certificates and can successfully operate in the managed open scenario where no infrastructure is pre-deployed. The basic mechanism used in ARAN is certification that is achieved through the existence of a trusted certification authority (CA). All nodes are supposed to know their public key from the certification authority and also the public key of server. Prior to entering into the network, each node has to apply for a certificate that is signed by the certificate server. ARAN accomplishes the discovery of routes by a broadcast message from source node which is replied in a unicast manner. This route discovery of the ARAN protocol begins with a node broadcasting to its neighbors a route discovery packet (RDP). The RDP includes the certificate of the initiating node, a nonce, a timestamp and the address of the destinatio n node. Furthermore, the initiating node signs the RDP. Each node validates the signature with the certificate, updates its routing table with the neighbor from which it received the RDP, signs it, and forwards it to its neighbors after removing the certificate and the signature of the previous node (but not the initiators signature and certificate). The signature prevents malicious nodes from injecting arbitrary route discovery packets that alter routes or form loops [13]. The destination node eventually receives the RDP and replies with a reply packet (REP). The REP contains the address of the source node, the destinations certificate, a nonce, and the associated timestamp. The destination node signs the REP before transmitting it. The REP is forwarded back to the initiating node by a process similar to the one described for the route discovery, except that the REP is unicasted along the reverse path. The source node is able to verify that the destination node sent the REP by chec king the nonce and the signature. Figure 2 illustrates the process of route discovery in ARAN. All messages are authenticated at each hop from source to destination as well as on the reverse path. Due to heavy computation involved with the certificates, ARAN is vulnerable to many attacks e.g. DOS attacks. In situation when there are no malicious nodes in the network the load involved in the routing process force the legitimate nodes to drop the packets in order to save their resources. Symmetric Cryptography Solutions Symmetric cryptographic solutions rely solely on symmetric cryptography to secure the function of routing in wireless ad hoc networks. The mechanisms utilized is hash functions and hash chains. A one-way hash function is a function that takes an input of arbitrary length and returns an output of fixed length [14]. As hash functions are especially lightweight when compared to other symmetric and asymmetric cryptographic operations, they have been extensively used in the context of securing ad hoc routing. Secure Ad hoc On-demand Distance Vector Protocol (SAODV) The Secure Ad hoc On Demand Distance Vector (SAODV) [7] addresses the problem of securing a MANET network. SAODV is an extension of AODV[4] routing protocol that can be used to protect the route discovery mechanism by providing security features like authentication, integrity and non-repudiation. It uses digital signatures to authenticate the non-mutable fields of the message, and hash chains to secure the hop count information (the only mutable field in message) in both RREQ and RREP messages. The SAODV scheme is based on the assumption that each node possesses certified public keys of all network nodes . In order to facilitate the transmission of the information required for the security mechanisms, SAODV defines extensions to the standard AODV message format. These SAODV extensions consist of the following fields. The hash function field identifies the one-way hash function that is used. The field max hop count is a counter that specifies the maximum number of nodes a packet is al lowed to go through. The top hash field is the result of the application of the hash function max hop count times to a randomly generated number, and finally the field hash is this random number. When a node transmits a route request or a route reply AODV packet it sets the max hop count field equal to the time to live (TTL) field from the IP header, generates a random number and sets the hash field equal to it, and applies the hash function specified by the corresponding field max hop count times to the random number, storing the calculated result to the top hash field. Moreover, the node digitally signs all fields of the message, except the hop count field from the AODV header and the hash field from the SAODV extension header. An intermediate node that receives a route request or a route reply must verify the integrity of the message and the hop count AODV [4] field. The integrity requirement is accomplished by verifying the digital signature. The hop count field is verified by comparing the result of the application of the hash function max hop count minus hop count times to the hash field with the value of the top hash field. Before the packet is re-broadcasted by the in termediate node the value of the hash field is replaced by the result of the calculation of the one-way hash of the field itself in order to account for the new hop. In SAODV route error messages (RERR) that are generated by nodes that inform their neighbors that they are not going to be able to route messages to specific destinations are secured using digital signatures. A node that generates or forwards a route error message cryptographically signs the whole message, except the destination sequence numbers. Although SAODV provides reasonable security to MANETs routing, but it is still vulnerable to distance fraud attack [15] in which the forwarding node fails to increment the route metric because in SAODV there is no enforcement to do so. Further there is no method to detect the malicious nodes and DOS attacks because in SAODV it is assumed that DOS attacks are restricted to physical layer, but this assumption failed when colluding malicious nodes drop packets during the route discovery process. Security Aware Routing (SAR) SAR [16] (Security Aware Routing) is an extension to existing on demand routing protocols and used where nodes are grouped on the basis of trust level. In SAR each node has different security level which assigns them different trust levels. Two nodes can only communicate with each other if they have equal or greater trust values. If a node has lower security level it simply discards the packet. In case there is no node in the network with the desired level then communication cannot take place or we can say that, that particular packet cant be forwarded unless its security level is lowered. By exploiting this condition a malicious node can attack at its level or at lower levels. Particularly in the context of Packet Dropping Attack, within a trust level, a malicious node or any other node which aims at saving its resources or intentionally launching a attack can successfully drop packets without being noticed and can get services from other nodes for forwarding its own packets. SAR al so fails in the situations of secure routing in general because it only focuses on the situations in which certain groups are assumed to be trustworthy. Conclusion From the above discussion, we observe that all Secure Ad hoc routing protocols are still vulnerable to many attacks. Although proposed techniques provide security against external attacks, insider attacks are still an open issue in MANETs. Chapter 3 Literature Review Introduction Many solutions have been proposed to prevent selfishness in MANETs. The main goal of all the schemes proposed in the literature is to make decisions regarding trustworthy entities and to encourage behavior that leads to increasing trust. In this section we discuss some of the solutions presented in the literature in order to detect the malicious nodes in the network in context of packet dropping attack. Watchdog and Pathrater In [17] Marti el al, proposed a mechanism called as watchdog and pathrater on DSR[6] to detect the misbehavior of nodes in MANETs. Nodes in this scheme operate in a promiscuous mode. The watchdog monitors one hop neighbor by overhearing the medium to check whether the next neighbor forwards the packet or not. It also maintains a buffer of recently sent packets. If a data packet remains in the buffer too long, the watchdog declares the next hop neighbor to be misbehaving. Every node that participates in the ad hoc network employs the watchdog functionality in order to verify that its neighbors correctly forward packets. When a node transmits a packet to the next node in the path, it tries to promiscuously listen if the next node will also transmit it. Furthermore, if there is no link encryption utilized in the network, the listening node can also verify that the next node did not modify the packet before transmitting it . The watchdog of a node maintains copies of recently forwarded p ackets and compares them with the packet transmissions overheard by the neighboring nodes. Positive comparisons result in the deletion of the buffered packet and the freeing of the related memory. If a node that was supposed to forward a packet fails to do so within a certain timeout period, the watchdog of an overhearing node increments a failure rating for the specific node. This effectively means that every node in the ad hoc network maintains a rating assessing the reliability of every other node that it can overhear packet transmissions from. A node is identified as misbehaving when the failure rating exceeds a certain threshold bandwidth. The source node of the route that contains the offending node is notified by a message send by the identifying watchdog. As the authors of the scheme note, the main problem with this approach is its vulnerability to blackmail attacks. The pathrater selects the path with the highest metric when there are multiple paths for the same destination node. The algorithm followed by the pathrater mechanism initially assigns a rating of 1.0 to itself and 0.5 to each node that it knows through the route discovery function. The nodes that participate on the active paths have their ratings increased by 0.01 at periodic intervals of 200 milliseconds to a maximum rating of 0.8. A rating is decremented by 0.05 when a link breakage is

Modern Piracy With A Breif History Essay -- essays research papers fc

Piracy is usually determined as a seizure of property (ship, airplane or software) that holds no commission from the owner (â€Å"Piracy† 1). It is mostly linked to the dirty, bearded men that sailed the seven seas and robed merchant ships or ships that carried a valuable cargo. This however, was not the case in the late eighties and is definitely not the case today in the nineties. Now software pirates copy software without the permission of the company for their own personal benefits. Since piracy interrupts trade between nations it has been considered to be an offense against international law (â€Å"Piracy† 1). While the pirates in the medieval age roamed for plunder on the high seas, pirate radio and television stations broadcast, unauthorized software pirates copy to save money and even if one form vanished, another would soon take its place. Although the roots of piracy go as far as 102 BC the true sea pirates golden age was between the time periods of the very late 1600’s and the year of 1923 when almost all pirates suddenly disappeared. Pirates attacked the Romans as early as 100 BC. This was not as rough as the future pirates would be, but the idealism of piracy was present. The so-called piracy’s golden age started in 1695 when the first famous pirate, Henry Every, began seizing sizable treasures in the Red Sea and this made him an idol to many unemployed seamen in England. Piracy offered no more risks than being on board an ordinary merchant or privateering (which is often confused with piracy) vessel and the returns could be indescribably greater than in trade or attacking enemy ships. This started an increase in the number of pirates. Soon, in some parts of the world, for example Nassau, there were so many pirate vessels sailing the seas that the trade between the colonies and the outside world was n onexistent because all the goods ended up in the pirate vessels. Although their ways were inhumane and sometimes highly brutal, they had some sort of passion to sail the unknown and break the law to fight a war on the ordinary world. Some pirates were famous for their incredible brutality or for their otherwise colorful personalities: Edward Teach (alias Black Beard), who terrorized the coastline of North Carolina in 1716-1718; Captain Kidd who was more known for his highly publicized trial than his wrongdoings; and Bartholomew Roberts who was the last and... ...mplies with the law, and that it issues an appropriate policy statement that is signed and respected by all involved (Software Publishers' Association). The sea pirates, the software pirates Hackers and the on the air pirates all have something in common. They all (with the exception of software pirates) do their job for the passion of it. All of these forms are considered illegal because of the losses made to the owner to save costs or to collect prizes (sometimes). Whatever the case, piracy can never be gotten rid of because a new form will show up when another vanishes, history proves that. What will the next form be? Use your imagination. Works Cited Botting, Douglas. â€Å"The Pirates.† Alexandria, Virginia: Time Life Books 1978. â€Å"Piracy.† Grolier Multimedia Encyclopedia. 1995. â€Å"Software Piracy.† CQ Researcher. May 21, 1993 MAS. Byrd, Kelly V. "Kelly's Place" Computer and Law http://www.acsu.buffalo.edu/~kbyrd/piracy.html: Spring 1996. Software Publishers' Association. "Software Use and the Law". http://www.spa.org/piracy/homepage.html: November 20, 1996. Computers In Society 6th ed. Dushkin Group/Brown&Benchmark Publishers: Guilford, CT, 1996.

Crushing the Native Americans

After the Civil War, Indians inhabited almost half of the United States. White Americans were urged to move west and settle, not taking regard that Native Americans already lived there. By the late 1800s most Indians had lost their land and had been driven onto reservations. Eastern Indians had already been forced to the west. A number of tribes weren't cooperative with moving onto reservations and changing their customs. This caused many battles between whites and Native Americans.During the Gold Rush of 1849, a lot of Native Americans were killed by white disease and minors burning their villages. These events were significant because they contributed to an up rise between white Americans and Indians. On November 29, 1864, Colonel John M. Chivington led an attack on the Cheyeane and Arapaho. They killed and scalped men, women, and children. I believe this was important because it showed the disregard for the tribes and how ruthless the whites were against them, but also warranted a treaty. The Fetterman massacre that took place in December 1866 was a big part of theSioux War of 1865-1867. Red Cloud, the Sioux Chief, lured Fetterman's army into an ambush and wiped out all of them. This took place again because of gold rush invasion and only shows the results of someone trying to take another's homeland. http://www. indians. org/articles/native-american-indians. html The Native American Indians were forced out of their homeland, resulting in many issues and events including the Trail of Tears. Most of them eventually converted to the European way of life by dressing the same and changing their religion to Christianity.

Conduct a Swot Analysis Essay

These range from one star to Five star deluxe depending upon size and amenities. About 30% of the rooms fall under the 5-star deluxe categories. To find out the present status of this industry a strength, weakness opportunity and threat (SWOT) analysis is mental. This will help us in understanding this industry and also identify the weak spots. S. W. O. T ANALYSIS OF HOTEL INDUSTRY Strengths ? A very wide variety of hotels is present in the country that can fulfill the demand of the tourists. ? There are international players in the market such as Taj and Oberoi & International Chains. Thus, the needs of the international tourists travellers are met while they are on a visit to India. ? Manpower costs in the Indian hotel industry is one of the lowest in the world. This provides better margins for Indian hotel industry. ? India offers a readymade tourist destination with the resources it has. Thus the magnet to pull customers already exists and has potential grow. Weaknesses ? The cost of land in India is high at 50% of total project cost as against 15% abroad. This acts as a major deterrent to the Indian hotel industry. ? The hotel industry in India is heavily staffed. This can be gauged from he facts that while Indian hotel companies have a staff to room ratio of 3:1, this ratio is 1:1 for international hotel companies. ? High tax structure in the industry makes the industry worse off than its international equivalent. In India the expenditure tax, luxury tax and sales tax inflate the hotel bill by over 30%. Effective tax in the South East Asian countries works ou t to only 4-5%. ? Only 97,000 hotel rooms are available in India today, which is less than the Bangkok hotel capacity. ? The services currently offered by the hotels in India are only limited value added services. It is not comparable to the existing world standards. Opportunities ? Demand between the national and the inbound tourists can be easily managed due to difference in the period of holidays. For international tourists the peak season for arrival is between September to March when the climatic conditions are suitable where as the national tourist waits for school holidays, generally the summer months. ? In the long-term the hotel industry in India has latent potential for growth. This is because India is an ideal destination for tourists as it is the only country with the most diverse topography. For India, the inbound tourists are a mere 0. 49% of the global figures. This number is expected to increase at a phenomenal rate thus pushing up the demand for the hotel industry. ? Unique experience in heritage hotels. Threats ? Guest houses replace the hotels. This is a growing trend in the west and is now catching up in India also, thus diverting the hotel traffic. ? Political turbulence in the area reduces tourist traffic and thus the business of the hotels. In India examples of the same are Insurgency in Jammu Kashmir and the Kargil war. ? Changing trends in the west demand imilar changes in India, which here are difficult to implement due to high project costs. ? The economic conditions of a country have a direct impact on the earnings in hotel industry. Lack of training man power in the hotel industry. Transport Facilities A well knit and coordinated system of transport plays an important role in the sustained economic growth of the country. The present transport system of th e country comprises of several modes of transport including rail, road, air transport etc. Tourism industry is also affected by the performance of these services heavy road taxes are the great threat to the tourism industry.

Human Resources Information System Essay

A Human Resources Management System (HRMS) or Human Resources Information System (HRIS), refers to the systems and processes at the intersection betweenhuman resource management (HRM) and information technology. It merges HRM as a discipline and in particular its basic HR activities and processes with the information technology field, whereas the programming of data processing systems evolved into standardized routines and packages of enterprise resource planning (ERP) software. On the whole, these ERP systems have their origin on software that integrates information from different applications into one universal database. The linkage of its financial and human resource modules through one database is the most important distinction to the individually and proprietary developed predecessors, which makes this software application both rigid and flexible. There are approximately 36 vendors of HRMS software in the U. S. and Canada[1]. The function of human resources (HR) departments is generally administrative and common to all organizations. Organizations may have formalized selection, evaluation, and payroll processes. Efficient and effective management of â€Å"human capital† progressed to an increasingly imperative and complex process. The HR function consists of tracking existing employee data which traditionally includes personal histories, skills, capabilities, accomplishments and salary. To reduce the manual workload of these administrative activities, organizations began to electronically automate many of these processes by introducing specialized human resource management systems. HR executives rely on internal or external IT professionals to develop and maintain an integrated HRMS. Before the client–server architecture evolved in the late 1980s, many HR automation processes were relegated to mainframe computers that could handle large amounts of data transactions. In consequence of the high capital investment necessary to buy or program proprietary software, these internally developed HRMS were limited to organizations that possessed a large amount of capital. The advent of client–server, application service provider, and software as a service (SaaS) or human resource management systems enabled increasingly higher administrative control of such systems. Currently human resource management systems encompass[citation needed]: 1. Payroll 2. Time and attendance 3. Performance appraisal 4.  Benefits administration 5. HR management information system 6. Recruiting/Learning management 7. Performance record 8. Employee self-service 9. Scheduling 10. Absence management 11. Analytics The payroll module automates the pay process by gathering data on employee time and attendance, calculating various deductions and taxes, and generating periodic pay cheques and employee tax reports. Data is generally fed from the human resources and time keeping modules to calculate automatic deposit and manual cheque writing capabilities. This module can encompass all employee-related transactions as well as integrate with existing financial management systems. The time and attendance module gathers standardized time and work related efforts. The most advanced modules provide broad flexibility in data collection methods, labor distribution capabilities and data analysis features. Cost analysis and efficiency metrics are the primary functions. The benefits administration module provides a system for organizations to administer and track employee participation in benefits programs. These typically encompass insurance, compensation, profit sharing and retirement. The HR management module is a component covering many other HR aspects from application to retirement. The system records basic demographic and address data, selection, training and development, capabilities and skills management, compensation planning records and other related activities. Leading edge systems provide the ability to â€Å"read† applications and enter relevant data to applicable database fields, notify employers and provide position management and position control. Human resource management function involves the recruitment, placement, evaluation, compensation and development of the employees of an organization. Initially, businesses used computer based information systems to: * produce pay checks and payroll reports; * maintain personnel records; * pursue talent management. Online recruiting has become one of the primary methods employed by HR departments to garner potential candidates for available positions within an organization. Talent management systems typically encompass: * analyzing personnel usage within an organization; identifying potential applicants; * recruiting through company-facing listings; * recruiting through online recruiting sites or publications that market to both recruiters and applicants. The significant cost incurred in maintaining an organized recruitment effort, cross-posting within and across general or industry-specific job boards and maintaining a competitive exposure of availabilities has given rise to the deve lopment of a dedicated applicant tracking system, or ‘ATS’, module. The training module provides a system for organizations to administer and track employee training and development efforts. The system, normally called a â€Å"learning management system† (LMS) if a stand alone product, allows HR to track education, qualifications and skills of the employees, as well as outlining what training courses, books, CDs, web based learning or materials are available to develop which skills. Courses can then be offered in date specific sessions, with delegates and training resources being mapped and managed within the same system. Sophisticated LMS allow managers to approve training, budgets and calendars alongside performance management and appraisal metrics. The employee self-service module allows employees to query HR related data and perform some HR transactions over the system. Employees may query their attendance record from the system without asking the information from HR personnel. The module also lets supervisors approve O. T. requests from their subordinates through the system without overloading the task on HR department. Many organizations have gone beyond the traditional functions and developed human resource management information systems, which support recruitment, selection, hiring, job placement, performance appraisals, employee benefit analysis, health, safety and security, while others integrate an outsourced applicant tracking system that encompasses a subset of the above. Assigning Responsibilities Communication between the Employees. The Analytics module enables organizations to extend the value of an HRMS implementation by extracting HR related data for use with other business intelligence platforms. For example, organizations combine HR metrics with other business data to identify trends and anomalies in headcount in order to better predict the impact of employee turnover on future output.