For many different applications, current information about the bandwidth-related metrics of the utilized connection is very useful as they directly impact the performance of throughput sensitive applications such as streaming servers, IPTV and VoIP applications. In literature, several tools have been proposed to estimate major bandwidth-related metrics such as capacity, available bandwidth and achievable throughput. The vast majority of these tools fall into one of Packet Pair (PP), Variable Packet Size (VPS), Self-Loading of Periodic Streams (SLoPS) or Throughput approaches. In this study, seven popular bandwidth estimation tools including nettimer, pathrate, pathchar, pchar, clink, pathload and iperf belonging to these four well-known estimation techniques are presented and experimentally evaluated in a controlled testbed environment. Differently from the rest of studies in literature, all tools have been uniformly classified and evaluated according to an objective and sophisticated classification and evaluation scheme. The performance comparison of the tools incorporates not only the estimation accuracy but also the probing time and overhead caused.

Nowadays, with growing of computer's networks and Internet, the security of data, systems and applications is becoming a real challenge for network's developers and administrators. An intrusion detection system is the first and reliable technique in the network's security that is based gathering data from computer network. Further, the need for monitoring, auditing and analysis tools of data traffic is becoming an important factor to increase an overall system and network security by avoiding external attackers and monitoring abuse of the IT assets by employees in the workplace. The techniques that used for collecting and converting data to a readable format are called packet sniffing. Packet Sniffer is a tool that used to capture packets in binary format, converts that binary data into a readable data format and log of that captured data for analyzing and monitoring, displaying different used applications, clear-text user names, passwords, and other vulnerabilities. It is used by network administrator to keep the network is more secured, safe and to support better decision. There are many different sniffing tools for monitoring, analyzing, and reporting the network's traffic. In this paper we will compare between three different sniffing tools; TCPDump, Wireshark, and Colasoft according to various parameters such as their detection ability, filtering, availability, supported operating system, open source, GUI, their characteristics and features, qualitative and quantitative parameters. In addition, this paper may be considered as an insight for the new researchers to guide them to an overview, essentials, and understanding of the packet sniffing techniques and their working.

Mobile apps are gaining in popularity and are becoming an indispensable part of our digital lives. Several mobile apps (such as messaging apps) contain personal/private information of the users. Inevitably, the compromise of accounts associated with such sensitive apps can result in disastrous consequences for the end user. Recently, Password Reset Man-in-the-Middle (PRMitM) attack was proposed at the application level in which an attacker can take over a user’s web account while the user is trying to access/download resources from the attacker’s website. In this work, we adapt this attack so that it can be applied in the context of mobile messaging apps. Specifically, we analyze 20 popular mobile messaging apps for vulnerability to MitM attack, 10 of which support secure communication through end-to-end encryption. Based on our holistic analysis, we have identified 10 of the tested apps as being vulnerable to MitM attack and elaborated on the corresponding attack scenarios. On comparing the secure messaging apps to non-secure messaging apps for vulnerability to MitM attack, we found that an app’s features and design choices decide if it is susceptible to MitM attack irrespective of whether it provides end-to-end encryption or not. Further, we have proposed design improvements to increase the overall security of all mobile messaging apps against MitM attack.

A bitcoin node needs to download the full block contents of the entire blockchain, before actually being able to send and receive transactions on bitcoin broadcast network, except simple payment verification clients which require only block headers and bloom filters to sync with others peers available on the network. Transactions/Blocks pass through a complex process at sender and receiver than it apparently looks to be. During transmission transactions/blocks are broken down into smaller chunks of data so that they can be carried on the wire. These chunks are given appropriate headers, encapsulated and then passed through several layers to reach the destination. In this paper we captured Bitcoin packets using Wireshark and deeply investigated and analyzed them. We investigated how bitcoin transaction/block messages work and what values and parameters are considered during this whole process.

Mobile Ad-Hoc networks (MANETs) can be classified as Decentralized, Independent and Self- Organizing dynamic networks of intellectual movable nodes. In such networks, devices are connected by provisional wireless links. Dynamic topology imposes challenges in developing an efficient routing protocol, for enabling successful communication between mobile devices. Based on the nature of working, proactive & reactive protocols are the two broadly classified categories of routing protocols. This paper presents, relative experimental analysis of proactive routing protocols viz., Optimized Link State Routing Protocol (OLSR) and its variant (Kenji Yamada et al., 2010) with Cooperative Multi-Point Relay (MPR) Selection. To compare OLSR and its variant protocol, the Network Simulator- 2.35 is used to carry out numerous simulations, on arbitrary scenarios, by varying the number of network nodes & mobility of nodes. As per the simulation outcomes, the OLSR with a cooperative MPR selection has outperformed the traditional OLSR protocol in static scenarios or when the network load has been varied. On the contrary, the traditional OLSR protocol has performed better in mobile scenarios. But, as demonstrated from various experimentations, it exhibits higher Routing Overheads as compared to its variant protocol. Further, on the basis of simulation results, efforts can be made in the direction of performance optimization of OLSR and its variant protocol, to improve its performance in highly mobile scenarios as well, keeping in view other performance metrics.

Information plays a pre-eminent role in people's routine lives. It provides people with facts about abundant topics of interest. Information can be represented by a variety of communicative media such as text, video, audio, and image, out of which text is the most common medium for representing the information. In the digital era, the information can easily be imitated, exchanged and distributed from one place to another in an instant. Thus, it is incredibly essential to hide the confidential information so that it couldn’t be accessed by unauthorized means. The traditional information hiding techniques require a designated carrier to hide the secret information, which ultimately introduces some modifications in the carrier. As a result, it is quite hard for the existing traditional methods to escape from the steganalysis. In contrast to conventional information hiding techniques, the term ‘coverless information hiding’ has been coined by the researchers lately, which doesn’t require a designated carrier to conceal the secret information. Hence, the technique of coverless information hiding can efficiently resist the attacks of steganalysis. This paper presents a state-of-the-art survey of coverless text information hiding by discussing the current scope of the aforementioned technique comprehensively. The existing coverless text information hiding methods are compared and contrasted by various vital aspects such as embedding capacity, algorithm efficiency, ability to resist steganalysis, and methods’ theoretical and real-world significance. Moreover, some future aspects of coverless text information hiding are highlighted at the end.

Today, Due to mobility wireless network have a heavy demand especially for wireless Ad-Hoc network. In Ad-Hoc network a group of wireless mobile nodes cooperate with each other by routing of packets. So it is necessary to design a wireless network which gives the best performance by suitable protocol selection and path routing. The selection of protocol should be suitable in terms of data integrity as well as data delivery. Hence performance evaluation of protocol is a major issue before selection of a routing protocol. In this paper our aim is to analyse the performance matrices including end to end delay, jitter, packet loss and packet delivery fraction of multi hop network by simulation. Performance evaluation of wireless ad hoc network routing protocols specially Ad-hoc On Demand Distance Vector (AODV), Optimized Link State Routing (OLSR), Destination Sequenced Distance Vector (DSDV) have been completed using NS-3 Simulator. After simulation we have found that OLSR routing protocol gives the best result comparison to AODV and DSDV in large and dense network.