Showing posts with label mca JAVAprojects. Show all posts

Wednesday, 21 October 2015

Maximizing P2P File Access Availability in Mobile Ad hoc Networks Though Replication for Efficient File Sharing

ABSTRACT:

File sharing applications in mobile ad hoc networks (MANETs) have attracted more and more attention in recent years. The efficiency of file querying suffers from the distinctive properties of such networks including node mobility and limited communication range and resource. An intuitive method to alleviate this problem is to create file replicas in the network. However, despite the efforts on file replication, no research has focused on the global optimal replica creation with minimum average querying delay. Specifically, current file replication protocols in mobile ad hoc networks have two shortcomings. First, they lack a rule to allocate limited resource to different files in order to minimize the average querying delay. Second, they simply consider storage as resource for replicas, but neglect the fact that the file holders’ frequency of meeting other nodes also plays an important role in determining file availability. Actually, a node that has a higher meeting frequency with others provides higher availability to its files. This becomes even more evident in sparsely distributed MANETs, where nodes meet disruptively. In this paper, we introduce a new concept of resource for file replication, which considers both node storage and meeting frequency. We theoretically study the influence of resource allocation on the average querying delay and derive a resource allocation rule to minimize the average querying delay. We further propose a distributed file replication protocol to realize the proposed rule. Extensive trace-driven experiments with synthesized traces and real traces show that our protocol can achieve shorter average querying delay at a lower cost than current replication protocols.

AIM

The aims of resource allocation on the average querying delay and derive a resource allocation rule to minimize the average querying delay

SCOPE

The Scope of this paper synthesized traces and real traces show that our protocol can achieve shorter average querying delay at a lower cost than current replication protocols.

EXISTING SYSTEM

In these protocols, each individual node replicates files it frequently queries, or a group of nodes create one replica for each file they frequently query. In the former, redundant replicas are easily created in the system, wasting resources. In the latter, though redundant replicas are reduced by group cooperation, neighboring nodes may separate from each other due to node mobility, leading to large query delay. There are also some works addressing content caching in more sparsely distributed MANETs (disconnected MANETs/DTNs) for efficient data retrieval or message routing current file replication protocols lack a rule to allocate limited resource to different files for replica creation in order to achieve the minimum global average querying delay, i.e., global search efficiency optimization under limited resource. Moreover, they simply consider storage as the resource for replicas, but neglect that a node’s frequency to meet other nodes (meeting ability in short) also influences the availability of its files. Files in a node with a higher meeting ability have higher availability.

DISADVANTAGES:

They lack a rule to allocate limited resource to different files in order to minimize the average querying delay
They simply consider storage as resource for replicas, but neglect the fact that the file holders’ frequency of meeting other nodes also plays an important role in determining file availability

PROPOSED SYSTEM

In this paper, introduce a new concept of resource for file replication, which considers both node storage and node meeting ability. We theoretically study the influence of resource allocation on the average querying delay and derive an optimal file replication rule that allocates resources to each file based on its popularity and size. To the best of our knowledge, this work is the first attempt to theoretically investigate the problem of resource allocation for replica creation to achieve global file searching optimization in MANETs. We further propose a file replication protocol based on the rule, which approximates the minimum global querying delay in a fully distributed manner. Our experiment and simulation results show the superior performance of the proposed protocol in comparison with other representative replication protocols

ADVANTAGES

An optimal replication rule to allocate the limited resource to file replicas in order to minimize the average querying delay
The Priority Competition and Split replication protocol (PCS) that realizes the proposed optimal replication rule in a fully distributed manner

SYSTEM ARCHITECTURE:

SYSTEM CONFIGURATION

HARDWARE REQUIREMENTS:-

· Processor - Pentium –III

· Speed - 1.1 Ghz

· RAM - 256 MB(min)

· Hard Disk - 20 GB

· Floppy Drive - 1.44 MB

· Key Board - Standard Windows Keyboard

· Mouse - Two or Three Button Mouse

· Monitor - SVGA

SOFTWARE REQUIREMENTS:-

· Operating System : Windows 7

· Front End : JSP AND SERVLET

· Database : MYSQL

· Tool :NETBEANS

REFERENCE:

Kang Chen, Haiying Shen. “Maximizing P2P File Access Availability in Mobile Ad hoc Networks Though Replication for Efficient File Sharing”, IEEE Transactions on Computers, Volume 64, Issue 4 FEBRUARY 2014.

Practical Secret Key Agreement for Full-Duplex Near Field Communications

Abstract

Near Field Communication (NFC) is a promising short distance radio communication technology for many useful applications. Although its communication range is short, NFC alone does not guarantee secure communication and is subject to security attacks, such as eavesdropping attack. Generating a shared key and using symmetric key cryptography to secure the communication between NFC devices is a feasible solution to prevent various attacks. However, conventional Diffie-Hellman key agreement protocol is not preferable for resource constrained NFC devices due to its extensive computational overhead and energy consumption. In this paper, we propose a practical, fast and energy-efficient key agreement scheme, which uses random bits transmission with waveform shaking, for NFC devices by exploiting its off-the-shelf full-duplex capability. In the proposed method, two devices send random bits to each other simultaneously without strict synchronization or perfect match of amplitude and phase. On the contrary, the method randomly introduces synchronization offset and mismatch of amplitude and phase for each bit transmission in order to prevent a passive attacker from determining the generated key. A shared bit can be established when two devices send different bits. We conduct theoretical analysis on the correctness and security strength of the method, and extensive simulations to evaluate its effectiveness. We build a test bed based on USRP software defined radio and conduct proof-of-concept experiments to evaluate the method in a real-world environment. It shows that the proposed method achieves a high key generation rate of about 26kbps and is immune to eavesdropping attack even when the attacker is within several centimeters from the legitimate devices. The proposed method is a practical, fast, energy-efficient, and secure key agreement scheme for resource-constrained NFC devices.

Aim

The main aim is to provide a practical, fast, energy-efficient, and secure key agreement scheme for resource-constrained NFC devices.

Scope

We propose a practical and energy efficient key agreement method for duplex NFC.

Existing System

Existing works indicate that using symmetric key cryptography to secure the NFC is a practical solution to protect against many kinds of attacks. It is mentioned in that due to the inherent protection of NFC against Man-in-the-Middle- Attacks, standard key agreement protocols like Diffie- Hellman based on RSA or Elliptic Curves could be applied to establish symmetric keys. Many works focus on finding the least expensive protocol for NFC and RFID. However, standard key agreement protocols intrinsically have extensive computational overhead and energy consumption. They are not preferable for resource constrained NFC devices. The works in proposed specific key agreements. The idea is for both devices to send random bits at exactly the same time. For the case when two parties send different bits, the attacker will not be able to identity which device sent the 0 and which device sent the 1. However, this concept is difficult to be implemented in practice due to the strict requirement of perfect synchronization as well as amplitude and phase match. This issue has been discussed in detail in this paper. The works in proposed Physical layer key generation methods by using the wireless channel measurements. By exploiting the reciprocal property of the wireless fading channel between two NFC devices, shared secret key can be generated. The methods have low computational overhead compared with standard key agreement protocols. However, the key generation rate is low. The time interval between two effective measurements of channel randomness is bounded by coherence time. Moreover, the methods have multiple steps including advantage distillation, information reconciliation and privacy amplification, which add computation and transmission overhead and time consumption.

Disadvantages

Proposed System

· This project proposes a key agreement scheme for NFC devices by exploiting its duplex capability. The method neither require perfect time synchronization nor absolute match of signal amplitude and phase. It tackles the impact of Gibbs phenomenon.

· We prove the correctness of the proposed method analytically, and demonstrate its effectiveness by simulations.

· We build a test bed based on USRP software defined radio and conduct proof-of-concept experiments to evaluate the effectiveness and security strength of the proposed method in a real-world environment.

We make the following findings:

· The proposed method can generate a shared key between two NFC devices at a high rate of about 26kbps.

· The proposed method is immune to eavesdropping attacks even when the attacker is a few centimeters from the legitimate users.

In this project we propose our method to prevent an eavesdropper from breaking the key when there are inevitable non-perfect synchronization, mismatch of signal amplitude and phase, and the impact of Gibbs phenomenon. The basic idea of our method is to add randomness into Alice’s and Bob’s RF signal (xa(t) and xb(t)) to make the signals received by Eve indistinguishable under case 1 and case 2. The randomness we introduce include 1) time shifting, 2) amplitude scaling, and 3) phase shifting, which are used to tackle out of synchronization, amplitude mismatch, and phase mismatch, respectively. We add guard bits or create a ‘null-signal area’ between consecutive bits to deal with the impact of Gibbs phenomenon

Advantages

· This project achieves a high key generation rate of about 26kbps and is immune to eavesdropping attack even when the attacker is within several centimeters from the legitimate devices.

· Our proposed method overcomes major problems in NFC key generation. It is a practical, fast, energy efficient, and secure key agreement scheme for resource constrained NFC devices.